[GMCnet] SUPER Brake Booster Aux Vacuum Pump

[Rob Mueller]

G'day,

Here's a SUPER brake booster Aux Vacuum Pump for our GMC's

http://www.ebay.com/itm/Ford-Continental-Electric-Vacuum-Pump-12VDC-Ford-A426C-/370691272503

I purchased two of them and they really SUCK! ;-)

At $115 with free shipping they are a bargain compared to anything else out there. If you read the blurb you will note that they
were meant to go in an electric vehicle sold in Europe that has been discontinued (Ford Azure). That means they were the ONLY vacuum
source for the brake booster so they had to be designed to be ultra reliable. I took one of these suckers apart and found that the
internals are very simple and crank / connecting rods run on bearings!

Because they have dual diaphragms they suck a lot more than any other pump on the market.

Unfortunately you will have to come up with a mounting bracket as none are available commercially.

If you buy one you will note that the plastic 3/8" barb fitting has a little tab that fits in a slot on the pump that keeps it from
rotating, with a small Dremel tool you can remove the barb and the fitting will rotate 360 degrees.

More photos:

http://www.gmcmhphotos.com/photos/g6633-brake-booster-vacuum-pump.html

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428

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[Larry]

Rob,
Looking a the photos, I don't get a sense of how big this thing is. Also, is this the same pump that Dave L has been using in his Brakes seminar at
GMCMI?
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.

[Ken Henderson]

Rob,

Thanks for the link. I'm tinkering with brakes a bit again so I ordered
one.

Just a few days ago I was redoing vacuum lines and decided to disconnect
the OLD Delco pump I've had on, but probably inoperative, for years. I
mounted the JC4 (which I've had for about 5 years) on the electric wiper
base, but haven't yet gotten around to connecting it -- partially because
I'm not enthusiastic about the 18-19 in-hg it produces. This sounds like a
better choice.

Have you yet designed a mounting bracket?

Ken H.

On Tue, Jul 15, 2014 at 9:39 AM, Rob Mueller <robmu...@iinet.net.au>
wrote:

> G'day,
>
> Here's a SUPER brake booster Aux Vacuum Pump for our GMC's
>
>
> http://www.ebay.com/itm/Ford-Continental-Electric-Vacuum-Pump-12VDC-Ford-A426C-/370691272503
>
> I purchased two of them and they really SUCK! ;-)
>
> At $115 with free shipping they are a bargain compared to anything else
> out there. If you read the blurb you will note that they
> were meant to go in an electric vehicle sold in Europe that has been
> discontinued (Ford Azure). That means they were the ONLY vacuum
> source for the brake booster so they had to be designed to be ultra
> reliable. I took one of these suckers apart and found that the
> internals are very simple and crank / connecting rods run on bearings!
>
> Because they have dual diaphragms they suck a lot more than any other
> pump on the market.
>
> Unfortunately you will have to come up with a mounting bracket as none
> are available commercially.
>
> If you buy one you will note that the plastic 3/8" barb fitting has a
> little tab that fits in a slot on the pump that keeps it from
> rotating, with a small Dremel tool you can remove the barb and the
> fitting will rotate 360 degrees.
>
> More photos:
>
> http://www.gmcmhphotos.com/photos/g6633-brake-booster-vacuum-pump.html
>
>

[Emery Stora]

This is identical to the one I purchased from Dave Lenzi at the Montgomery convention.
He also sell a nicely machined adapter that fits into the booster that has a check valve and a pressure regulator and a vacuum gauge. I'll take a picture and post it to the photos site. I didn't find it necessary to rotate the fitting. A simple bracket was made from two steel "l" brackets with 6" legs. I cut on leg to about 5" and drilled holes and attached it to the pump with metric bolts and secured the other leg to the firewall beneath the steering column. It works well.

Emery Stora

[Ken Henderson]

Emery,

I take it it's quiet enough, or runs so seldom, that you found no need for
isolators?

Ken H.

On Tue, Jul 15, 2014 at 3:32 PM, Emery Stora <emery...@mac.com> wrote:

> This is identical to the one I purchased from Dave Lenzi at the Montgomery
> convention.
> He also sell a nicely machined adapter that fits into the booster that
> has a check valve and a pressure regulator and a vacuum gauge. I'll take a
> picture and post it to the photos site. I didn't find it necessary to
> rotate the fitting. A simple bracket was made from two steel "l" brackets
> with 6" legs. I cut on leg to about 5" and drilled holes and attached it
> to the pump with metric bolts and secured the other leg to the firewall
> beneath the steering column. It works well.
>

[Bob de Kruyff]

Ken Henderson wrote on Tue, 15 July 2014 14:04

> Emery,
>
> I take it it's quiet enough, or runs so seldom, that you found no need for
> isolators?
>
> Ken H.
>

> On Tue, Jul 15, 2014 at 3:32 PM, Emery Stora wrote:
>
> > This is identical to the one I purchased from Dave Lenzi at the Montgomery
> > convention.
> > He also sell a nicely machined adapter that fits into the booster that
> > has a check valve and a pressure regulator and a vacuum gauge. I'll take a
> > picture and post it to the photos site. I didn't find it necessary to
> > rotate the fitting. A simple bracket was made from two steel "l" brackets
> > with 6" legs. I cut on leg to about 5" and drilled holes and attached it
> > to the pump with metric bolts and secured the other leg to the firewall
> > beneath the steering column. It works well.
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

I've been a strong proponent of a reserve tank rather than a pump, but that is such a nice looking unit that I had to buy one :)
--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[John Wright]

I also bought one today to replace the JC4 which I have mounted up front. I will look forward to seeing the pictures of your unit Emory.

JR Wright
78 Buskirk Stretch
75 Avion
Michigan

[Guy Lopes]

Wow, he's selling these like hotcakes! I just bought one as well. I also
bought an Oldsmobile emblem from him ($5.00) that I think will look good
cemented to my air cleaner. Lol

Guy Lopes
76 Birchaven "Orion"
Sacramento, CA
W6TOL

www.GMC-Guy.com

[Emery Stora]

It can be heard when it runs but


Emery

[Ken Henderson]

Bob,

The PVC reserve tank I've had installed for the past 12-13 years is the
reason I haven't worried about the status of the Delco pump. This new
pump, like that one, will be redundant with the tank. But I plan to
monitor it more closely. And if it's as good as Rob says, it will probably
provide more vacuum than the tank usually holds.

Ken H.

[Kerry Pinkerton]

Yes, this appears to be the same the unit that Dave Lenzi used in his test rig at Montgomery. As Rob said, it really sucks. It goes from nothing to
full vacuum in a second or two. So quiet you can't hear it running inside the coach. I can hear my JC4 with the engine on and it leaks down so it
runs from time to time.

Dave also has some super duper check valves. I have yet to install mine. I'll make up an aluminum bracket and probably put some rubber isolators on
it just to protect it from bumps and jars.

As far as size goes, it's about 5" long and 4 tall and 4 wide...or thereabouts. Doesn't weight much.
--
Kerry Pinkerton

North Alabama, near Huntsville,

77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76 Eleganza to be re-bodied as an Art Deco car hauler

[Carl Stouffer]

powerjon wrote on Tue, 15 July 2014 15:42

> I also bought one today to replace the JC4 which I have mounted up front. I will look forward to seeing the pictures of your unit Emory.
>
> JR Wright
> 78 Buskirk Stretch
> 75 Avion
> Michigan

This is just what I love about this forum. I just installed a JC-4 last year and now I find that it has been replaced as the forum favorite. :roll:

--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.

[Steve Weinstock]

Carl -

I know EXACTLY what you mean...

Kind of related to the recent thread about unfinished projects - my JC4 is still waiting to be installed and I purchased one of these too !!

There'll be a new JC4 in the classifieds pretty soon. I think I even have the mounting bracket...

Steve W
1973 23'
Southern California

[Carl Stouffer]

SteveW wrote on Tue, 15 July 2014 20:09

> Carl -
>
> I know EXACTLY what you mean...
>
> Kind of related to the recent thread about unfinished projects - my JC4 is still waiting to be installed and I purchased one of these too !!
>
> There'll be a new JC4 in the classifieds pretty soon. I think I even have the mounting bracket...
>
> Steve W
> 1973 23'
> Southern California

Go for it Steve. I'm going to stick with the JC-4. I'm sure it is adequate.

Another thing I love about this forum is that even though I have never had a major problem with the coach in six years and 22,000 miles, I am getting
nervous about the week long trip we have planned beginning this Saturday. I read about all this gloom and doom and can't help but wonder what
horrible thing is going to happen to me. I should probably take a hiatus from the net for a few weeks before a trip. I suspect this trip will come
off without a hitch like all the other ones, but I can't help but feel uneasy.

--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.

[gene Fisher]

And
And

Let's see how the install is
And
And
Are they still available

I will stick with the JC4
But like options

Erf

--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html

[Rob Mueller]

Bob,

As a former GM executive buying a pump for a FORD must have been painful!

VVVVBG!

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428

[Ken Burton]

That same guy has been selling those for a couple of years on ebay. He must have bought a couple of pallets of them. Obviously Ford did not use them
after they bought them. I wonder why.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Kerry Pinkerton]

Ken Burton wrote on Wed, 16 July 2014 05:55
> ... Obviously Ford did not use them after they bought them. I wonder why.


Dave said the car never went into production.

--
Kerry Pinkerton

North Alabama, near Huntsville,

77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76 Eleganza to be re-bodied as an Art Deco car hauler

[Bob de Kruyff]

""Bob,

As a former GM executive buying a pump for a FORD must have been painful!

VVVVBG!

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428
""

It is one of the bigger regrets in my life :)
--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Rob Mueller]

G'day,

Here you go: http://en.wikipedia.org/wiki/Azure_Transit_Connect_Electric

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428


-----Original Message-----

From: Ken Burton

That same guy has been selling those for a couple of years on ebay. He must have bought a couple of pallets of them. Obviously
Ford did not use them after they bought them. I wonder why.
--
Ken

[John Wright]

Rob,
What about the connector pinout on the pump and is there a connector available? I guess that I will have to see what the connector is like and see if I can find one at the men’s mall.

JR Wright
GMC Great Laker MHC
GMC Eastern States
GMCMHI
78 GMC Buskirk 30’ Stretch
1975 GMC Avion (Under Reconstruction)
Michigan

[Emery Stora]

You don't need a connector. Two leads go to a connector and one wire goes to ground. For the connector, I cut it off and used two bullet connectors. You could also use spade connectors but I liked the bullet connectors with a small piece of heat sharing tubing.

Be sure to use a relay. I have the wiring diagram at home but we are on a trip and won't be home until Sunday.

I recall that one lead goes to a constant battery and the other goes to an ignition circuit. You have to have an external pressure regulator as one is not built into the pump.

Emery Stora

[Bill Wevers]

I bought one.
Couldn't pass up a good deal.

[John Wright]

Ordered it yesterday and it arrived today before Noon. Shipped from Livonia, just about 90 miles south of me.

JR Wright
78 Buskirk Stretch
75 Avion

Michigan

[John Wright]

Powered it up, work very well, has one red and one brown wire. Red is power and brown is ground. Will build the same setup I used for the old GM vacuum pumps that we could get back around 1999. I used a Hobbs Vacuum Switch Part#77343 4 NC which means no vacuum then the switch and open at your set point. As Emery says you should always used a relay as you could damage the switch with high starting current load.

<http://www.gmcmhphotos.com/photos/vacuum-pump-vacuum-switch/p55250-vacuum-pressure-switch.html>
and
http://www.gmcmhphotos.com/photos/vacuum-pump-vacuum-switch/p1615.html


J.R. Wright
GMC Great Laker MHC
Newsletter Editor/Publisher

GMC Eastern States
GMCMHI
78 GMC Buskirk 30’ Stretch

75 GMC Avion (Under Reconstruction)
Michigan

On Jul 16, 2014, at 12:35 PM, Bill Wevers <gmc...@att.net> wrote:

[D C _Mac_ Macdonald]

I also just ordered one. 16 left, 21 sold in last 24 hours! Act quickly!

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~~ k2gkk + hotmail dot com ~~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
______________
*[ ]~~~[][ ][|\
*--OO--[]---O-*

[Emery Stora]

Rather than rely on a faulty memory I just looked at mine.
Tha wire from a source that is hot with the key on goes to the pressure switch. From the pressure switch it goes to the relay coil. The other side of the coil goes to ground. The lead from the battery (hot all the time) goes to one relay contact. The other relay contact goes to the red lead of the pump. The other pump lead (brown) goes to ground.

Even at 5000 ft elevation I could get 20" of vacuum.
Emery Stora

[Keith V]

So whats wrong with the good ol JC4 I'm just getting hooked up now.

You guys are changing things too fast for me!
--
Keith
69 Vette
29 Dodge
75 Royale GMC
Mounds View. MN

[gene Fisher]

Prob like this
http://www.gmcmhphotos.com/photos/vacuum-pumps-new-models/p4752.html

Clearly more complex than this
http://www.gmcmhphotos.com/photos/vacuum-pumps-new-models/p24284-jc4-pump1.html

Which is made for this application and better, in the long run

Erf

On Wednesday, July 16, 2014, Emery Stora <emery...@mac.com> wrote:

> Rather than rely on a faulty memory I just looked at mine.
> Tha wire from a source that is hot with the key on goes to the pressure
> switch. From the pressure switch it goes to the relay coil. The other side
> of the coil goes to ground. The lead from the battery (hot all the time)
> goes to one relay contact. The other relay contact goes to the red lead of
> the pump. The other pump lead (brown) goes to ground.
>
> Even at 5000 ft elevation I could get 20" of vacuum.
> Emery Stora
>
> > On Jul 16, 2014, at 1:07 PM, John Wright <powe...@chartermi.net

> <javascript:;>> wrote:
> >
> > Powered it up, work very well, has one red and one brown wire. Red is
> power and brown is ground. Will build the same setup I used for the old GM
> vacuum pumps that we could get back around 1999. I used a Hobbs Vacuum
> Switch Part#77343 4 NC which means no vacuum then the switch and open at
> your set point. As Emery says you should always used a relay as you could
> damage the switch with high starting current load.
> >
> > <
> http://www.gmcmhphotos.com/photos/vacuum-pump-vacuum-switch/p55250-vacuum-pressure-switch.html
> >
> > and
> > http://www.gmcmhphotos.com/photos/vacuum-pump-vacuum-switch/p1615.html
> >
> >
> > J.R. Wright
> > GMC Great Laker MHC
> > Newsletter Editor/Publisher
> > GMC Eastern States
> > GMCMHI
> > 78 GMC Buskirk 30’ Stretch
> > 75 GMC Avion (Under Reconstruction)
> > Michigan
> >
> >> On Jul 16, 2014, at 12:35 PM, Bill Wevers <gmc...@att.net

> <javascript:;>> wrote:
> >>
> >> I bought one.
> >> Couldn't pass up a good deal.
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>

--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html

[gene Fisher]

Yours is the best
http://gmcmotorhome.info/addens.html#jc4
Erf

--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html

[Charles Boyd]

Sir: is that a Tecumseh AC compressor you are using for an air compressor? Looks like about a 1/2 hp motor turning it. NICE..





[quote title=powerjon wrote on Tue, 15 July 2014 18:42]I also bought one today to replace the JC4 which I have mounted up front. I will look forward

to seeing the pictures of your unit Emory.

JR Wright
78 Buskirk Stretch
75 Avion
Michigan

--
C. Boyd
76 Crestmont
East Tennessee

[Charles Boyd]

SORRY
http://www.gmcmhphotos.com/photos/vacuum-pump-vacuum-switch/p1608.html



[quote title=C Boyd wrote on Wed, 16 July 2014 18:16]Sir: is that a Tecumseh AC compressor you are using for an air compressor? Looks like about a 1/2

hp motor turning it. NICE..

[John Wright]

Charles,
What you seen in the picture is a Darcy Moses air compressor setup that I bought from him at the GMCMI Myrtle Beach rally, I think that it was spring of 1999. Worked really well, I could run small air tools with it. Darcy passed on a number of years ago and nobody ever pick up on making the unit. It was driven with a chevy starter motor. It was installed in our first coach that was sold in 2011 when we bought the stretch coach. You could actually watch the coach raise up!

JR Wright
78 Buskirk Stretch
75 Avion
Michigan

[Bob de Kruyff]

""G'day,

Here's a SUPER brake booster Aux Vacuum Pump for our GMC's

http://www.ebay.com/itm/Ford-Continental-Electric-Vacuum-Pump-12VDC-Ford-A426C-/370691272503

I purchased two of them and they really SUCK! ;-)""

How do people plan on turning on the pump? Vacuum switch or activated by brake application?

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Emery Stora]

You need an adjustable vacuum switch and a relay. I can provide a wiring diagram if needed.

I bought mine from Dave Lenzi.

Emery Stora
77 Kingsley
Frederick, CO

[Bob de Kruyff]

""You need an adjustable vacuum switch and a relay. I can provide a wiring diagram if needed.

I bought mine from Dave Lenzi.

Emery Stora
77 Kingsley
Frederick, CO
""

The reason I asked, some of the guys had hooked up the JC4 pump directly to the brake circuit and seemed satisfied. This pump must have a lot more
capacity and may be adequate, but it seems a vacuum switch would allow the system to be there before you need it.

[Rob Mueller]

Bob,

Standby, I have parts on order that will allow me to put together a comprehensive installation document which will cover:

1) How to make a mounting bracket
2) Where to get a vacuum switch
3) Where to locate the pump
4) How to plumb it into the system
5) How to wire it

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428


-----Original Message-----

From: Bob de Kruyff

How do people plan on turning on the pump? Vacuum switch or activated by brake application?
--
Bob

[Bob de Kruyff]

""Bob,

Standby, I have parts on order that will allow me to put together a comprehensive installation document which will cover:

1) How to make a mounting bracket
2) Where to get a vacuum switch
3) Where to locate the pump
4) How to plumb it into the system
5) How to wire it

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428

I received mine the other day and it sure is a nice looking unit. I suspect Delphi must make it for Ford :)

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[gene Fisher]

like this
http://www.gmcmhphotos.com/photos/vacuum-pumps-new-models/p4752.html

or

like this
http://www.gmcmhphotos.com/photos/vacuum-pumps-new-models/p24284-jc4-pump1.html

make your choice

On Tue, Jul 22, 2014 at 10:49 AM, Rob Mueller <robmu...@iinet.net.au>
wrote:

> Bob,

--

Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html

[Ken Henderson]

Rob,

Not trying to steal your thunder but maybe help: Looks like mine will have
to mount beneath the R. Front battery tray on the side of the frame rail.
A 5"X5"X1/8" angle bracket 7" long will bolt to the side of the frame.
Four 3/8"X1" bolts vertically through the horizontal flange will receive
3" sections of 3/8" ID fuel hose. The pump will sit on those isolators.
You'll find that the pump's mounting studs are 3-3/4" apart on parallel
lines 2-3/4" apart; but, they're offset by 3/16" so that there are no 3
square.

To protect the pump and, especially, its air outlet from the elements and
the possible leakage from the batteries above it, I've found a plastic
cover: A trimmed up 1 gallon plastic gas can. It'll fit over the top of
the pump and extend most of the way down the sides. It can't come off
after the bracket with the pump is bolted to the frame.

​HTH,​

Ken H.

On Tue, Jul 22, 2014 at 1:49 PM, Rob Mueller <robmu...@iinet.net.au>
wrote:

> Bob,
>
> Standby, I have parts on order that will allow me to put together a
> comprehensive installation document which will cover:
>
> 1) How to make a mounting bracket
> 2) Where to get a vacuum switch
> 3) Where to locate the pump
> 4) How to plumb it into the system
> 5) How to wire it
>
>

[Bob de Kruyff]

Ken Henderson wrote on Wed, 23 July 2014 09:39

> Rob,
>
> Not trying to steal your thunder but maybe help: Looks like mine will have
> to mount beneath the R. Front battery tray on the side of the frame rail.
> A 5"X5"X1/8" angle bracket 7" long will bolt to the side of the frame.
> Four 3/8"X1" bolts vertically through the horizontal flange will receive
> 3" sections of 3/8" ID fuel hose. The pump will sit on those isolators.
> You'll find that the pump's mounting studs are 3-3/4" apart on parallel
> lines 2-3/4" apart; but, they're offset by 3/16" so that there are no 3
> square.
>
> To protect the pump and, especially, its air outlet from the elements and
> the possible leakage from the batteries above it, I've found a plastic
> cover: A trimmed up 1 gallon plastic gas can. It'll fit over the top of
> the pump and extend most of the way down the sides. It can't come off
> after the bracket with the pump is bolted to the frame.
>
> ​HTH,​
>
> Ken H.
>
> On Tue, Jul 22, 2014 at 1:49 PM, Rob Mueller

> wrote:
>
> > Bob,
> >
> > Standby, I have parts on order that will allow me to put together a
> > comprehensive installation document which will cover:
> >
> > 1) How to make a mounting bracket
> > 2) Where to get a vacuum switch
> > 3) Where to locate the pump
> > 4) How to plumb it into the system
> > 5) How to wire it
> >
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Now that you have already stolen the thunder, let me steal a little more:) Since I want it in this weekend, I'm making a mounting bracket with four
tubes that will accept the fuel line into which the mounting studs will sit. The bracket will have a circular hole to clear the motor. I've ordered
the adjustable vacuum switch off Ebay--it is designed to unlock transmission torque convertors on non electronic vehicles.
Sorry Rob but I was too impatient to wait.

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Rob Mueller]

Ken / Bob,

No worries, MATES!

I'm using vibration isolators with 6mm x 1 studs on them from Mc Master Carr as I figger by using them I can mount the pump any way I want to "right side up / up side down / sideways / catawampus."

It would be helpful if you guys would take photographs of your installations so people can make a choice where to put it.

Also I would appreciate knowing what you used for the vacuum switch.

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428

-----Original Message-----
From: Bob de Kruyff

Ken Henderson wrote on Wed, 23 July 2014 09:39
> Rob,
>
> Not trying to steal your thunder but maybe help: Looks like mine will have
> to mount beneath the R. Front battery tray on the side of the frame rail.
> A 5"X5"X1/8" angle bracket 7" long will bolt to the side of the frame.
> Four 3/8"X1" bolts vertically through the horizontal flange will receive
> 3" sections of 3/8" ID fuel hose. The pump will sit on those isolators.
> You'll find that the pump's mounting studs are 3-3/4" apart on parallel
> lines 2-3/4" apart; but, they're offset by 3/16" so that there are no 3
> square.
>
> To protect the pump and, especially, its air outlet from the elements and
> the possible leakage from the batteries above it, I've found a plastic
> cover: A trimmed up 1 gallon plastic gas can. It'll fit over the top of
> the pump and extend most of the way down the sides. It can't come off
> after the bracket with the pump is bolted to the frame.
>
> ​HTH,​
>
> Ken H.
>

[Bob de Kruyff]

""Ken / Bob,

No worries, MATES!

I'm using vibration isolators with 6mm x 1 studs on them from Mc Master Carr as I figger by using them I can mount the pump any way I want to "right
side up / up side down / sideways / catawampus."

It would be helpful if you guys would take photographs of your installations so people can make a choice where to put it.

Also I would appreciate knowing what you used for the vacuum switch.

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428

""

Hopefully I will have the bracket fabbed by Friday afternoon and I'll take some pics. Here is the vacuum switch I ordered:

http://www.ebay.com/itm/251096417522?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
http://www.ebay.com/itm/251096417522?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Ken Henderson]

Since I found a chunk of metal in my junk box that was already configured
close to the design I'd conceived, I went ahead and mounted the Azure SUPER
vacuum pump this afternoon:

http://www.gmcmhphotos.com/photos/g6638-azure-vacuum-pump.html

It's not connected yet; maybe tomorrow.

Ken H.

[Randy]

Carl S. wrote on Tue, 15 July 2014 20:39
> Go for it Steve. I'm going to stick with the JC-4. I'm sure it is adequate.
>
> Another thing I love about this forum is that even though I have never had a major problem with the coach in six years and 22,000 miles, I am
> getting nervous about the week long trip we have planned beginning this Saturday. I read about all this gloom and doom and can't help but wonder
> what horrible thing is going to happen to me. I should probably take a hiatus from the net for a few weeks before a trip. I suspect this trip will
> come off without a hitch like all the other ones, but I can't help but feel uneasy.

During my road testing, the power assist remains for one full brake application after the engine quits. A second pump is about 1/2 the assist and a
third is no assist (but the brakes still work). So the lesson should be for anyone is: if the engine quits - step on the brake and hold it until
you're basically stopped. The redundant systems are ok, but if they don't work and you cream a Ferrari your insurance company may not be impressed
with the electric pump. Good technique should be backed up with system redundancy. IMHO the pump and tanks are there in case you take your foot off
the brake accidentally in the event of engine failure.

I take my coach up and down mountains but I always remember the adage: "Don't go down a mountain faster than you would go up". If the engine quits
creeping down a mountain I hold steady pressure on the brake and if that's not doing it, she's headed for a controlled crash into the guard rail. JWID

--
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ

[Bob de Kruyff]

Ken Henderson wrote on Wed, 23 July 2014 16:52

Nice Ken. I've decided to hang mine from the wiper motor bracket outbard of the wiper unit itself. As soon as the crack team at U-Haul gets it fabbed,
I'll post pics. I'm mounting the standoffs inside a tube with rubber fuel line pieces about an inch long.

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[John Wright]

Ken,
Did you have a foto album on your work pit at the house? I would search but I don’t know what to call it.

JR Wright
78 Buskirk Stretch
75 Avion
Michigan

[Kerry Pinkerton]

powerjon wrote on Wed, 23 July 2014 19:01

> Ken,
> Did you have a foto album on your work pit at the house? I would search but I don't know what to call it.

> ...


Here it is Jon. http://www.gmcmhphotos.com/photos/g4271-ken-s-shop-amp-grease-rack.html

Having had the pleasure of working in Ken's pit, I can honestly say that short of a 4 post lift capable of lifting 12500 lbs, Ken's pit is near
perfect. The ability to stand upright beside the wheels/tires makes working on them a breeze. I could not imagine doing the Manny Brake or 1 ton
installation laying on the ground. I'm physically unable to sit crosslegged so working on the ground is a real challenge for me.



--
Kerry Pinkerton

North Alabama, near Huntsville,

77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76 Eleganza to be re-bodied as an Art Deco car hauler

[George Zhookoff]

[quote title=Kerry Pinkerton wrote

"The ability to stand upright beside the wheels/tires makes working on them a breeze. I could not imagine doing the Manny Brake or 1 ton installation
laying on the ground. I'm physically unable to sit crosslegged so working on the ground is a real challenge for me."

Hey I resemble that remark!
After 3 front ends at Bean Station, 1-pit/2-floor, 1 Reaction Arm using the pit and several visits to the famous "Ken's GMC Hut" in Americus I also
raise my hand in favor of Ken's approach.

George "total hip replacement courtesy of my Uncle Sam" Zhookoff
78 EL II
Atlanta

[Kerry Pinkerton]

Luvn737s wrote on Wed, 23 July 2014 19:56
> ....IMHO the pump and tanks are there in case you take your foot off the brake accidentally in the event of engine failure. ...


Since this pump was designed to provide the ONLY source of vacuum for the Azure vehicle, it's designed to very quickly regenerate vacuum. When Dave
had it set up in his test jig, it would only take a second or two...really, to reach the specified vacuum setting. Given that, an engine failure
would not keep you from pressing and releasing the pedal as often as you want as long as you have 12V available to the pump.

OK, I got a bit too hot today and my brain isn't working very well. Does 20 inches of vacuum give you more assist than 18"? I assume it does and if
so, with proper check valves, I'd think we'd be better off to run more vacuum to the brake booster than the engine can produce. In other words, let
the pump provide primary vacuum and the engine secondary.

Now if I can only remember where I put the fancy check valves that Dave L gave me.... :blush:

--
Kerry Pinkerton

North Alabama, near Huntsville,

77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76 Eleganza to be re-bodied as an Art Deco car hauler

[Emery Stora]

I purchased the pump from David Lenzi at the Montgomery, TX GMCMI convention.
He shipped me the machined adapter that he makes that plugs into the booster and which has a threaded port for the vacuum meter and a port on the front for a check valve for the hose that leads to the pump. In the bottom of the adapter is a threaded port that holds the vacuum switch. He sells a very accurate vacuum switch that is easy to adjust. Just grab ahold of the pump and rotate it to raise or lower the vacuum.

I found that the pump would give me 20" of vacuum even at 5200 feet above sea level. The engine only gives about 14" at that elevation. The higher vacuum will give better braking from the booster.

I fashioned the brackets for the pump from two 6" angles purchased from Home Depot.
You remove the four bolts that were designed to mount into rubber "feet" on the automobile. I bought 1" nylon spacers and metric bolts to hold the pump to the brackets and screwed the brackets to the firewall.

Pictures are here:

http://www.gmcmhphotos.com/photos/g6643-vacuum-pump-for-brakes-lenzi.html

Emery Stora
77 Kingsley
Frederick, CO

[Emery Stora]

That should have read grab ahold of the VACUUM SWITCH and rotate it.

Emery Stora

Begin forwarded message:

[Bob de Kruyff]

Bob de Kruyff wrote on Wed, 16 July 2014 06:25
> ""Bob,
>
> As a former GM executive buying a pump for a FORD must have been painful!
>
> VVVVBG!

>
> Regards,
> Rob M.
> The Pedantic Mechanic
> USAussie - Downunder
> USA '75 Avion - Double Trouble TZE365V100426
> AUS '75 Avion - The Blue Streak TZE365V100428
> ""
>

> It is one of the bigger regrets in my life :)

I'm starting to post pictures of my Bosch vacuum pump install. Rob, did you notice I'm trying not to use the F--d word?
http://www.gmcmhphotos.com/photos/super-vacuum-pump/p55351-installation-of-the-bosch-vacuum-pump.html

http://www.gmcmhphotos.com/photos/super-vacuum-pump/p55351-installation-of-the-bosch-vacuum-pump.html

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Guy Lopes]

Ken,

I just received my vacuum pump. I planned to mount mine on the driver's side
near the brake booster. I also have plans to install your electric
windshield wiper conversion in the near future. Did you decide to mount
yours where you did because of a conflict between these two systems, or
another reason?

Just trying to educate myself for planning purposes.

Thanks,

Guy Lopes
76 Birchaven "Orion"
Sacramento, CA
W6TOL

www.GMC-Guy.com

-----Original Message-----
From: gmclist...@temp.gmcnet.org
[mailto:gmclist...@temp.gmcnet.org] On Behalf Of Ken Henderson
Sent: Wednesday, July 23, 2014 3:53 PM
To: gmclist
Subject: Re: [GMCnet] SUPER Brake Booster Aux Vacuum Pump

[Ken Henderson]

Guy,

I've got several other devices mounted in the area around the wiper
assembly which I didn't want to move to accomodate the new vacuum pump,
else I might have mounted it in that area. So I really didn't check for
space.

I'll have my pump back off for plumbing and wiring, probably on Monday, and
will check whether it would have been feasible to mount it there without
the other obstructions. I'll let you know; others are sure to be curious
also.

Ken H.

[Guy Lopes]

Indeed!

[Bob de Kruyff]

Well it is in and running. Not too much fun in this heat but at least it didn't break any records today. I still have some minor wiring to finish to
the relay but it is plumbed. I jumpered it and it is quiet and very strong. It goes from a depleted system (including my PVC reservoir to shut off in
about 6 seconds or less at a setting of 15". I'm going to crank the vacuum switch to max vacuum and see what happens at around 25".

http://www.gmcmhphotos.com/photos/super-vacuum-pump/p55368-img-1901.html

http://www.gmcmhphotos.com/photos/super-vacuum-pump/p55368-img-1901.html

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Kerry Pinkerton]

Nice installation Bob. Talked to Dave Lenzi yesterday. He runs his at 21" with no reservoir and told me that at that vacuum, I'd notice a marked
improvement in braking.

He mounted his up high on the firewall where the horns are and moved the horns to the bottom of his pump mount.

We were talking about some other things and he told me he had measured some of the JD4 pumps and some were only capable of 10 inches of vacuum.
Others got to 15.

--
Kerry Pinkerton

North Alabama, near Huntsville,

77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76 Eleganza to be re-bodied as an Art Deco car hauler

[A.]

Kerry Pinkerton wrote on Sun, 27 July 2014 19:25

> Nice installation Bob. Talked to Dave Lenzi yesterday. He runs his at 21" with no reservoir and told me that at that vacuum, I'd notice a marked
> improvement in braking.
>
> He mounted his up high on the firewall where the horns are and moved the horns to the bottom of his pump mount.
>
> We were talking about some other things and he told me he had measured some of the JD4 pumps and some were only capable of 10 inches of vacuum.
> Others got to 15.

So is it implied that the electric pump will be your primary source of vacuum for the booster and the engine vacuum will be your backup?

--
'73 23' Sequoia For Sale
'73 23' CanyonLands For Sale
Upper Alabama

[Ken Henderson]

Since there's a trapped vacuum in the booster and, perhaps, the reservoir,
the highest vacuum seen since the last brake application should be
available for braking. So neither the pump nor the engine can really be
considered "primary" -- usually the engine should provide 20-23 in-Hg
during deceleration so it would be dominant if the pump was set to 19
in-Hg. But if the engine only pulled 18 in Hg, the pump could be said to
be primary.

Personally, I've already tested the pump to 23" in Hg. If I can get it to
25 in Hg, that's where I plan to run. ​ Tuesday will probably be when I
get that installed and tested.

Ken H.

On Sun, Jul 27, 2014 at 9:42 PM, A. <mar...@netzero.com> wrote:

> Kerry Pinkerton wrote on Sun, 27 July 2014 19:25
> > Nice installation Bob. Talked to Dave Lenzi yesterday. He runs his at
> 21" with no reservoir and told me that at that vacuum, I'd notice a marked
> > improvement in braking.
> >
> > He mounted his up high on the firewall where the horns are and moved the
> horns to the bottom of his pump mount.
> >
> > We were talking about some other things and he told me he had measured
> some of the JD4 pumps and some were only capable of 10 inches of vacuum.
> > Others got to 15.
> So is it implied that the electric pump will be your primary source of
> vacuum for the booster and the engine vacuum will be your backup?
> --
> '

[Bob de Kruyff]

Kerry Pinkerton wrote on Sun, 27 July 2014 18:25

> Nice installation Bob. Talked to Dave Lenzi yesterday. He runs his at 21" with no reservoir and told me that at that vacuum, I'd notice a marked
> improvement in braking.
>
> He mounted his up high on the firewall where the horns are and moved the horns to the bottom of his pump mount.
>
> We were talking about some other things and he told me he had measured some of the JD4 pumps and some were only capable of 10 inches of vacuum.
> Others got to 15.

Thanks Kerry. When I first installed my PVC reservoir I noticed an improvement in braking effort. I assumed at the time that the reservoir was drawn
down to a fairly high level since on overrun it was able to store more vacuum than the engine would do at normal speeds.

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Bob de Kruyff]

A Hamilto wrote on Sun, 27 July 2014 19:42

> Kerry Pinkerton wrote on Sun, 27 July 2014 19:25
> > Nice installation Bob. Talked to Dave Lenzi yesterday. He runs his at 21" with no reservoir and told me that at that vacuum, I'd notice a
> > marked improvement in braking.
> >
> > He mounted his up high on the firewall where the horns are and moved the horns to the bottom of his pump mount.
> >
> > We were talking about some other things and he told me he had measured some of the JD4 pumps and some were only capable of 10 inches of
> > vacuum. Others got to 15.
> So is it implied that the electric pump will be your primary source of vacuum for the booster and the engine vacuum will be your backup?

Whichever has the best sucking power at the moment--no highschool jokes :)

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Kerry Pinkerton]

A Hamilto wrote on Sun, 27 July 2014 20:42
> ...So is it implied that the electric pump will be your primary source of vacuum for the booster and the engine vacuum will be your backup?



Well yes, if the pump is set to a higher vacuum than the motor can deliver. I have dual vacuum ports so one will be to the engine and one to the
pump. Whichever sucks the most will be 'primary' but I'm expecting the pump to win that battle most the time and Dave L agrees.

I'm planning on having a gauge inside the coach as well as one outside. As a test with the pump disabled, I'll be able to see what kind of vacuum the
engine will pull into the booster and then see what the changes when the pump is turned on.

I'm still thinking about reservoirs. It seems to me that it's kind of like an air compressor with a big tank. Even though the compressor would fill
up a small tank and shut off very quick, it will have to run a while to fill a larger tank. Same principal in reverse with a vacuum pump. If you
somehow depleted the storage tank, it would take longer to pull the same vacuum in the booster AND the tank than just the booster....I think.... I'm
still ruminating on this. If the pump will pull to 20 inches in a couple seconds from nothing, I'm not sure that the tank is an advantage...I
think....maybe.....

--
Kerry Pinkerton

North Alabama, near Huntsville,

77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76 Eleganza to be re-bodied as an Art Deco car hauler

[A.]

Kerry Pinkerton wrote on Sun, 27 July 2014 23:42

> Well yes, if the pump is set to a higher vacuum than the motor can deliver. I have dual vacuum ports so one will be to the engine and one to the
> pump. Whichever sucks the most will be 'primary' but I'm expecting the pump to win that battle most the time and Dave L agrees.
>
> I'm planning on having a gauge inside the coach as well as one outside. As a test with the pump disabled, I'll be able to see what kind of vacuum
> the engine will pull into the booster and then see what the changes when the pump is turned on.
>
> I'm still thinking about reservoirs. It seems to me that it's kind of like an air compressor with a big tank. Even though the compressor would
> fill up a small tank and shut off very quick, it will have to run a while to fill a larger tank. Same principal in reverse with a vacuum pump. If
> you somehow depleted the storage tank, it would take longer to pull the same vacuum in the booster AND the tank than just the booster....I think....
> I'm still ruminating on this. If the pump will pull to 20 inches in a couple seconds from nothing, I'm not sure that the tank is an advantage...I
> think....maybe.....

I'm also thinking sustaining the vacuum would hold the actuators in the dash heater/ac on hills better.

--
'73 23' Sequoia For Sale
'73 23' CanyonLands For Sale
Upper Alabama

[gene Fisher]

​

>
> ​
> ​
>
> I'm still thinking about reservoirs.

​i have never been in favor of brake system, reservoirs.

you are messing with a primary safety system, where there is an advantage
to reducing the number of components, connections, with their MTBF numbers.

if you read about a current , engineered, design, in current , use, and
manufacture
http://www.gmcmhphotos.com/photos/data/4896/Vacuum_pump.pdf

you will see a design , for this application, with one component, the
pump(available new), ​

​with no extra hoses, relays, sensors, pvc tanks, etc.

this design, is available for the gmc and was used by Jerry
work.

ENGINEERING - FOREVER :>)
jwid
erf
​

> It seems to me that it's kind of like an air compressor with a big tank.
> Even though the compressor would fill
> up a small tank and shut off very quick, it will have to run a while to
> fill a larger tank. Same principal in reverse with a vacuum pump. If you
> somehow depleted the storage tank, it would take longer to pull the same
> vacuum in the booster AND the tank than just the booster....I think.... I'm
> still ruminating on this. If the pump will pull to 20 inches in a couple
> seconds from nothing, I'm not sure that the tank is an advantage...I
> think....maybe.....
> --
> Kerry Pinkerton
>
> North Alabama, near Huntsville,
>
> 77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76
> Eleganza to be re-bodied as an Art Deco car hauler
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>

--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html

[Kerry Pinkerton]

A Hamilto wrote on Sun, 27 July 2014 23:50
> ...I'm also thinking sustaining the vacuum would hold the actuators in the dash heater/ac on hills better.


The vacuum from the pump is confined to the booster by the check valves.[/quote]

[Skip Hartline]

The last few posts bring up in interesting thought, could there be a limit on what is a good high vacuum ?
Skip Hartline

[Rob Mueller]

Skip,

The higher the vacuum the more brake boost, unfortunately to date I have not been able to find out what vacuum the Azure pump was
set to provide to the brake booster as installed.

I would say the limit would be dependant on the pumps design. I have PERSONALLY taken apart one of the Azure pumps and from what I
saw it is a very well designed and manufactured pump.

Frankly speaking it had to be as it was the ONLY source of vacuum for the booster as the Azure was an electric vehicle.

I will disassemble one, photograph the innards and show everybody what I found, come to think of it I just might buy a JC-4 and see
that that looks like internally as well.

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428

[Bob de Kruyff]

USAussie wrote on Mon, 28 July 2014 09:14

It will be interesting to see what the pump will do. My vacuum switch will adjust to 25". I suspect the engine vacuum will get that high on overrun
so I'm not expecting a dramatic change in booster performance, but probably more consistent.

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[D C _Mac_ Macdonald]

Helluva lot more than from an engine that is not running!

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~~ k2gkk + hotmail dot com ~~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
______________
*[ ]~~~[][ ][|\
*--OO--[]---O-*


> Date: Mon, 28 Jul 2014 09:39:44 -0600
> To: gmc...@temp.gmcnet.org
> From: NEXT...@gmail.COM

> Subject: Re: [GMCnet] SUPER Brake Booster Aux Vacuum Pump
>

> USAussie wrote on Mon, 28 July 2014 09:14
> > Skip,
> >
> > The higher the vacuum the more brake boost, unfortunately to date I have not been able to find out what vacuum the Azure pump was
> > set to provide to the brake booster as installed.
> >
> > I would say the limit would be dependant on the pumps design. I have PERSONALLY taken apart one of the Azure pumps and from what I
> > saw it is a very well designed and manufactured pump.
> >
> > Frankly speaking it had to be as it was the ONLY source of vacuum for the booster as the Azure was an electric vehicle.
> >
> > I will disassemble one, photograph the innards and show everybody what I found, come to think of it I just might buy a JC-4 and see
> > that that looks like internally as well.
> >
> > Regards,
> > Rob M.
> > The Pedantic Mechanic
> > USAussie - Downunder
> > USA '75 Avion - Double Trouble TZE365V100426
> > AUS '75 Avion - The Blue Streak TZE365V100428
> >
> >
> > -----Original Message-----
> > From: Skip Hartline
> >
> > The last few posts bring up in interesting thought, could there be a limit on what is a good high vacuum ?
> > Skip Hartline
> >
>

[Kerry Pinkerton]

I just measured the output of my 'old' pump that came on the coach. I was using a non dampened gauge and the needle was swinging between 8 and 16 so
figure 12 inches of mercury for an average. Like Mac said, a lot more than a dead engine but I expect a to feel a considerable difference in required
pedal pressure at 20-22". I suppose this could be tested easily with an adjustable vacuum switch and a plugged engine vacuum hose. In fact, if I
recall correctly, Dave Lenzi showed all this in his seminar by varying the vacuum and reading the output pressure directly from the master cylinder.
What that doesn't indicate is how much a 50% increase in brake line PSI effects actual stopping. I need to dig up my notes from his seminar.

Another way of looking at all this is to consider pressure on the foot pedal (again, something Dave was measuring and controlling via a air
cylinder...smart, smart guy Dave is) What Dave showed is that for the same pedal pressure, changes in vacuum levels had a significant impact on
master cylinder PSI. Simply put, for the same stopping distance, you would not have to press as hard on the whoa pedal.

skip2 wrote on Mon, 28 July 2014 09:43

> The last few posts bring up in interesting thought, could there be a limit on what is a good high vacuum ?
> Skip Hartline

I wonder if Skip's question is if there is a limit on what the booster can consistently take? In other words can we oversuck the diaphragm and damage
it?

--
Kerry Pinkerton

North Alabama, near Huntsville,

77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76 Eleganza to be re-bodied as an Art Deco car hauler

[Skip Hartline]

That's what I meant, can the booster be damaged with too much vacuum?
Skip

[Bob de Kruyff]

skip2 wrote on Mon, 28 July 2014 11:46

> That's what I meant, can the booster be damaged with too much vacuum?
> Skip

I don't think so within the range we are operating. I don't have a vacuum gage on my coach but those that do may recall what they see when the coach
is decelerating down a hill. I suspect a good 455 cid vacuum pump can out do this little guy :)

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Ken Henderson]

Kerry,

Seems to me the natural atmospheric pressure is the only possible limit to
what the booster can take.

Maybe the next time we're together we can run some instrumented tests.
I'll finish my Super Vacuum installation today. I've mounted the vacuum
switch where the adjusting screw is immediately accessible. I still have
the pneumatic pedal puller installed so we can applied controlled, known
pedal pressures. I also have fittings in both brake hydraulic circuits,
just below the vibration loops at the MC, for ease of connecting line
pressure gauges, which I probably have. About the only additional things
we need are time and patience (given that we can't get Dave to come help).
:-)

Ken H.


On Mon, Jul 28, 2014 at 12:20 PM, Kerry Pinkerton <Pinke...@mchsi.com>
wrote:

[Hal Kading]

Ken,

I agree that atmospheric pressure is the key. If all the air is pumped out of the booster (perfect vacuum), the ambient atmospheric pressure is all
there is to push on the diaphragm. We'll get less braking boost here at 4450 ft msl than you will at 420 ft msl in Americus GA.

Hal Kading 78 Buskirk Las Cruces NM.

[Kerry Pinkerton]

Ken Henderson wrote on Mon, 28 July 2014 14:12
> ...Seems to me the natural atmospheric pressure is the only possible limit to
> what the booster can take....


Talked to Dave this afternoon. He agrees. We can't pull enough vacuum to hurt the booster.

Btw, Dave is bringing his test rig and doing the same seminar at in Wisconsin that he did in Montgomery. With all the talk of boosters and such, I'm
sure it will be a big hit and I'm hoping to be able to understand more the second time through. I STRONGLY recommend this seminar. It is GOOD
STUFF!

Btw, I'm an dumbass. At Montgomery, I got a couple of the higher quality check valves that Dave had. Couldn't find those darn things anywhere.
Looked all throughout the toad, and the coach, and my GMC corner. Nothing. I was still looking. Last week, I called him to get one of his aluminum
manifolds. When I got my pump from him, he was not making them so they weren't in the 'kit'. He was making some for other folks and said he's be
able to me one headed this way mid week. I called him today and asked him to add a vacuum gauge and a couple more of his check valves.

So just now, I'm in the coach digging out the extra Airtex 4070 Fuel Pump for project # next and take another swing through the coach looking for the
check valves. For some reason, I decided to look in the kitchen drawers. In the silverware drawer were the check valves, AND the manifold and vacuum
gauge that I didn't even remember I got from him. I have no frigging idea why I put them in the silverware drawer. 8o :blush:

I called Dave to say 'never mind' and told him the story. We both got a laugh out of it.

--
Kerry Pinkerton

North Alabama, near Huntsville,

77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76 Eleganza to be re-bodied as an Art Deco car hauler

[Emery Stora]

Ken
You may be able to set it at 23" now at your present location but if you take a trip and go up in elevation you will likely have to reset the vacuum to a lower amount.

At my house approx. 5200 ft elevation I was able to set it at 21". However when I went up to the Rocky Mountain National Park last weekend I found that the pump wanted to run full time when I got up to 8000 ft elevation. I had to adjust it down to 19" to shut off the pump. If I had gone to the top visitor center at 12000 feet (which I did with the toad) I am sure that I would have had to set it even lower to keep it from running full time.

So, for the present I am leaving it at 19".

Dave Lenzi had also told me that I would have much better braking with this pump. I totally agree with him. The higher vacuum on the booster gives much better brakes.

Emery Stora

[Emery Stora]

On Jul 28, 2014, at 7:07 AM, Kerry Pinkerton <Pinke...@MCHSI.com> wrote:

> A Hamilto wrote on Sun, 27 July 2014 23:50
>> ...I'm also thinking sustaining the vacuum would hold the actuators in the dash heater/ac on hills better.
>
>
> The vacuum from the pump is confined to the booster by the check valves.[/quote]
>
> --
> Kerry Pinkerton
>

Yes, but when I had the GM pump I put in a tee and provided more vacuum to the heater/ac actuators and they did operate much faster.
However, if you have a leak anywhere in the system then your pump will come on more often.

Emery Stora

[Emery Stora]

I would really doubt it. A higher vacuum would seal it better if there is a small leak for example at the check valves.

Emery Stora

[Ken Henderson]

Emery, et al,

I made my first attempt at setting the Super Vacuum Pump today. I didn't
get to complete the process so perhaps should keep my thoughts to myself
for now. But I observed a peculiarity which I wish others would examine:

With the switch set for On=23 in-Hg Off=21 in-Hg (yep, it has that little
hysteresis), with a well sealed system, the pump operates as one would
expect. BUT, when I introduced a serious leak into the system (bled it
rapidly to below about 15 psi) the switch closed (as indicated by the
attached indicator light) but the pump did NOT come on. Only after a delay
of up to 15 seconds at 0 in-Hg would the pump come back on. Even more
peculiarly, it would then shut off at about 15 in-Hg, though the indicator
was still on. Repeated "rapid decompressions" resulted in the same
strange behavior. But if the leak was eliminated, that is, no rapid
decompression was allowed, the pump would again respond to the 23/21 in-Hg
commands of the switch. It acts as if there's an internal self-protection
switch that's governed by vacuum change rate. That makes no sense to me in
a vehicle safety device, but that's the impression it gives.

I have not yet had a chance to eliminate all other possibilities, such as a
thermal CB opening, but I don't believe that's likely. Some of you who're
set up for testing, please give this scenario a try.

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, etc., etc.
www.gmcwipersetc.com

[Bob de Kruyff]

Ken, I'm considering isolating the reservour and taking it out of the brake system with a check valve. Mine is cycling perfectly with the switch I
have. It is powerfull enough that I am thinking of using the PVC reservoir for the HVAC system alone.

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Rob Mueller]

Ken,

This makes no sense at all!

I can't see how it's the pump as all it has is two leads to the motor. When I took it apart I couldn't find any kind of pressure
sensing device anywhere in it.

I would suggest that you disconnect the inlet hose to the pump and feed power directly to the motor.

When I connected the motor leads to a battery the pump started instantly and when I disconnect them it stopped..

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428


-----Original Message-----
From: gmclist...@temp.gmcnet.org [mailto:gmclist...@temp.gmcnet.org] On Behalf Of Ken Henderson
Sent: Thursday, July 31, 2014 9:51 PM
To: gmclist
Subject: Re: [GMCnet] SUPER Brake Booster Aux Vacuum Pump

[Ken Henderson]

Rob,

I'm glad to hear you've disassembled the pump to confirm there's no
internal protective circuit. That means I've got some other problem. It's
really baffling because the indicator light is connected directly to the
+lead to the motor and stays at the same brightness when the motor refuses
to run. And the mystery is compounded by the fact that the motor always
runs as expected when the vacuum level changes slowly. I'll figure it out,
but not for a day or two. Headed out of town right now.

Ken H.

On Fri, Aug 1, 2014 at 12:30 AM, Rob Mueller <robmu...@iinet.net.au>
wrote:

> Ken,
>
> This makes no sense at all!
>
> I can't see how it's the pump as all it has is two leads to the motor.
> When I took it apart I couldn't find any kind of pressure
> sensing device anywhere in it.
>
> I would suggest that you disconnect the inlet hose to the pump and feed
> power directly to the motor.
>
> When I connected the motor leads to a battery the pump started instantly
> and when I disconnect them it stopped..
>
>

[Kerry Pinkerton]

Ken Henderson wrote on Thu, 31 July 2014 21:50
> ... But I observed a peculiarity which I wish others would examine:

>
> With the switch set for On=23 in-Hg Off=21 in-Hg (yep, it has that little
> hysteresis), with a well sealed system, the pump operates as one would
> expect. BUT, when I introduced a serious leak into the system (bled it
> rapidly to below about 15 psi) the switch closed (as indicated by the
> attached indicator light) but the pump did NOT come on. Only after a delay
> of up to 15 seconds at 0 in-Hg would the pump come back on. Even more
> peculiarly, it would then shut off at about 15 in-Hg, though the indicator
> was still on. Repeated "rapid decompressions" resulted in the same
> strange behavior. But if the leak was eliminated, that is, no rapid
> decompression was allowed, the pump would again respond to the 23/21 in-Hg
> commands of the switch. It acts as if there's an internal self-protection
> switch that's governed by vacuum change rate. That makes no sense to me in
> a vehicle safety device, but that's the impression it gives.
>
> I have not yet had a chance to eliminate all other possibilities, such as a
> thermal CB opening, but I don't believe that's likely. Some of you who're
> set up for testing, please give this scenario a try.

Ken, I can't explain that either. I got mine wired up this morning and it does NOT exhibit the behavior you describe. With my thumb over the second
port, I can dump ALL the vacuum and the pump starts running. Or, I can crack my thumb a bit and let it drop below the trigger level anywhere from 10
to 20 " Mercury and the pump immediately starts.

Since you know the switch is working because of the light, about the only thing that comes to mind is the relay itself creating some type of delay.

Btw, I have mine set at 23", it comes on at 21". From an empty booster, it takes 5" to get to 23" and 3 seconds to get to 15". When I press on the
brake pedal, the booster runs 3 seconds before it recovers. When I get the fuel system back together, I'll do some tests with the engine running.

--
Kerry Pinkerton

North Alabama, near Huntsville,

77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76 Eleganza to be re-bodied as an Art Deco car hauler

[Bob de Kruyff]

Kerry Pinkerton wrote on Sat, 02 August 2014 08:51

Mine's all wired and plumped. I works OK although I am getting some relay chatter upon shutoff. At the vacuum I have it set right now, it comes on
everytime I depress the brake. I may adjust it later since usually depressing the brake happens on overrun so it may not behave that way on the road.
I isolated the heck of it and it is noisier than I expected. I think any mounting on the front of dash is a problem. I mounted mine to the big bracket
that the wiper is mounted to but I can even hear the realy click. I guess overall I'm a bit under whelmed.

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Ken Henderson]

Well, I discovered part of my problem: For ease of connection, I jumpered the
trouble light into the relay coil rather than the output. That additional
load apparently reduced the drive current to the relay sufficiently to
prevent reliable operation. I haven't yet thoroughly tested all aspects of
possible operation and malfunction, but it operates properly in normal
operation -- parked, no road test yet.

My mounting location on the right front frame rail with the tubing
standoffs suppresses the noise pretty effectively: if the air conditioner
is on, I can't hear the pump.

My switch is set at 23/21 in-Hg. With the engine idling at 18 in-Hg,
depressing the pedal causes the pump to come on momentarily -- and again
when the brake is released (Lenzi booster). I want to try the brakes on
the road with this high setting, but I'll certainly reduce it before
heading to a higher altitude.

I temporarily re-routed my dash vacuum gauge to the vacuum reservoir and
had intended to add one dedicated to that purpose. But I'm now planning to
just install a pump power indicator iight. If that light's operating, the
dash override switch is on, as it should be. If the light's on, I"ve
obviously got less vacuum than the On setting; and, if it's running very
much, something's wrong. I really don't need more information than that.

Ken H.

On Sat, Aug 2, 2014 at 11:56 PM, Bob de Kruyff <NEXT...@gmail.com> wrote:

>
> Mine's all wired and plumped. I works OK although I am getting some relay
> chatter upon shutoff. At the vacuum I have it set right now, it comes on
> everytime I depress the brake. I may adjust it later since usually
> depressing the brake happens on overrun so it may not behave that way on
> the road.
> I isolated the heck of it and it is noisier than I expected. I think any
> mounting on the front of dash is a problem. I mounted mine to the big
> bracket
> that the wiper is mounted to but I can even hear the realy click. I guess
> overall I'm a bit under whelmed.
> --
>

[Kerry Pinkerton]

Bob de Kruyff wrote on Sat, 02 August 2014 22:56
> ...At the vacuum I have it set right now, it comes on everytime I depress the brake. I may adjust it later since usually depressing the brake

> happens on overrun so it may not behave that way on the road. I isolated the heck of it and it is noisier than I expected. I think any mounting on
> the front of dash is a problem. I mounted mine to the big bracket that the wiper is mounted to but I can even hear the realy click. I guess overall
> I'm a bit under whelmed.

I'm kind of surprised you are underwhelmed Bob. I totally expect the pump to run every time the pedal is depressed unless you have it set REALLY,
REALLY low.

I have mine mounted on the side of the radiator support:

http://www.gmcmhphotos.com/photos/misc/p55409-internals-0053.html


It's double isolated. The aluminum bracket I made uses rubber washers on both sides of the bolts that hold it to the mounting brackets on the
radiator support AND also on the bolts that mount the pump itself to the bracket.

I can hear it run but won't be able to when the motor is running. I could hear the old JC4 and it also came on every time I touched the brakes.

Btw, the relay you see wrapped in the electrical tape is not the pump relay but one for my backup camera. The pump relay is mounted to the pump
itself

--
Kerry Pinkerton

North Alabama, near Huntsville,

77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76 Eleganza to be re-bodied as an Art Deco car hauler

[Steve Southworth]

Kerry Pinkerton wrote on Sat, 02 August 2014 09:51
> [I got mine wired up this morning and it does NOT exhibit the behavior you describe.


Kerry - looking at your photo archive picture it appears you have a cube relay taped into the wiring harness with the terminals facing UP. If this is
correct I suggest you invert it so the terminals are down. These things can breathe moisture in where it condenses and eventually they fill up with
water and fail. You can ask me how I know this but you probably can guess.
--
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI

[Rob Mueller]

Bob,

I looked at your photos and you might want to replace the o-rings / grommets with McMaster Carr Neoprene Vibration Damping Sandwich
Mount P/N 9241K45 or P/N9225K67.

I intend to mount it to the top of the radiator frame using the two bolts that join the top of that frame to the sides and drill /
tap a couple more bolt holes in the frame.

You're not underwhelmed with the speed that the Azure pump evacuates the booster are you?

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428

-----Original Message-----

From Bob de Kruyff

Mine's all wired and plumped. I works OK although I am getting some relay chatter upon shutoff. At the vacuum I have it set right
now, it comes on everytime I depress the brake. I may adjust it later since usually depressing the brake happens on overrun so it
may not behave that way on the road. I isolated the heck of it and it is noisier than I expected. I think any mounting on the front
of dash is a problem. I mounted mine to the big bracket that the wiper is mounted to but I can even hear the realy click. I guess
overall I'm a bit under whelmed.
--
Bob

[Johnny Bridges]

I concur - that upside down relay wil lead you to grief much faster than if it is mounted top up.

--johnny

--
"Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon

[Bob de Kruyff]

USAussie wrote on Sun, 03 August 2014 07:56

I think I'll live with the noise for a while and see how it is on the road. It's not unpleasant and a little will at least let me know it is on. As
far as the capacity, it is good but not great in my mind. I was hoping I could pump the brakes and never deplete the vacuum, but eventually I do run
out of assist. It's probably not a realistic situation but considering that this is the only source for an electric vehicle, I expected unlimited
brake applications. I'm more upset about the relay chatter upon shutoff. In fact it isn't the relay that is the problem but rather the vacuum switch.
If I short across the vacuum switch, the on and off cylces are clean without any chatter. Today I'm going to isolate the reservoir with a check valve
and take it out of the brake system. Then I'll run my hvac doors off it to see if I get some better operation.

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Emery Stora]

Are you sure you don't have a leak somewhere? Mine comes on when I apply the brakes but goes off fairly quickly. If I take my foot off the brake and reapply it the pump again starts but I can do this repeatedly and it never seems to run out of assist even with the engine not running.

Emery Stora

On Aug 3, 2014, at 11:48 AM, Bob de Kruyff <NEXT...@gmail.COM> wrote:

>>
>
> I think I'll live with the noise for a while and see how it is on the road. It's not unpleasant and a little will at least let me know it is on. As
> far as the capacity, it is good but not great in my mind. I was hoping I could pump the brakes and never deplete the vacuum, but eventually I do run
> out of assist. It's probably not a realistic situation but considering that this is the only source for an electric vehicle, I expected unlimited
> brake applications. I'm more upset about the relay chatter upon shutoff. In fact it isn't the relay that is the problem but rather the vacuum switch.

> If I short across the vacuum switch, the on and off cycles are clean without any chatter. Today I'm going to isolate the reservoir with a check valve

> and take it out of the brake system. Then I'll run my hvac doors off it to see if I get some better operation.
> --
> Bob de Kruyff

[Bob de Kruyff]

emerystora wrote on Sun, 03 August 2014 11:58

> Are you sure you don't have a leak somewhere? Mine comes on when I apply the brakes but goes off fairly quickly. If I take my foot off the brake
> and reapply it the pump again starts but I can do this repeatedly and it never seems to run out of assist even with the engine not running.
>
> Emery Stora
>

> On Aug 3, 2014, at 11:48 AM, Bob de Kruyff wrote:
>
> >>
> >
> > I think I'll live with the noise for a while and see how it is on the road. It's not unpleasant and a little will at least let me know it is
> > on. As
> > far as the capacity, it is good but not great in my mind. I was hoping I could pump the brakes and never deplete the vacuum, but eventually I
> > do run
> > out of assist. It's probably not a realistic situation but considering that this is the only source for an electric vehicle, I expected
> > unlimited
> > brake applications. I'm more upset about the relay chatter upon shutoff. In fact it isn't the relay that is the problem but rather the vacuum
> > switch.
> > If I short across the vacuum switch, the on and off cycles are clean without any chatter. Today I'm going to isolate the reservoir with a
> > check valve
> > and take it out of the brake system. Then I'll run my hvac doors off it to see if I get some better operation.
> > --
> > Bob de Kruyff
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

I don't think I have a leak since after a day of sitting it still has vacuum in the system. It may be that I have to get the right switch setting and
suck it down further. My comments were with the engine off as well. I'll spend some more time with it today. The heat limits my fun factor on this. It
is a nice machine though.

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[D C _Mac_ Macdonald]

I'm just curious as to whether the difference in size of vehicles (Azure vs GMC MH) might come into play here.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~~ k2gkk + hotmail dot com ~~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
______________
*[ ]~~~[][ ][|\
*--OO--[]---O-*

> Date: Sun, 3 Aug 2014 11:48:29 -0600
> To: gmc...@temp.gmcnet.org
> From: NEXT...@gmail.COM

> Subject: Re: [GMCnet] SUPER Brake Booster Aux Vacuum Pump
>

[Rob Mueller]

Bob,

C'mon, this pump was designed for the Azure not a GMC. Since it was a 1791 Kg vehicle (3948 Lb) and I would think that the booster
would be sized for that size / weight vehicle.

http://en.wikipedia.org/wiki/Azure_Transit_Connect_Electric

You're not saying that Ford engineering is so stupid as to design a vehicle with a limited number of brake applications are you?

[gene Fisher]

do they even make this pump any more?
erf

--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html

[D C _Mac_ Macdonald]

My understanding (so far) is that the pump was originally intended to be the SOLE source of vacuum for the Azure. For our GMCs, is not its use intended as an emergency back up in case of engine vacuum failure? During "normal" operation our coaches, it would seem to me that the actual time of pump operation should be quite minimal and pump lifespan should probably outlast our coaches. Pump "turn-on" pressure should likely be set at several PSI under the vacuum normally provided by a running engine which would minimize run time.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~~ k2gkk + hotmail dot com ~~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
______________
*[ ]~~~[][ ][|\
*--OO--[]---O-*

> Date: Mon, 4 Aug 2014 06:43:25 -0700
> From: mr.er...@gmail.com
> To: gmc...@temp.gmcnet.org

> Subject: Re: [GMCnet] SUPER Brake Booster Aux Vacuum Pump
>

[Bob de Kruyff]

USAussie wrote on Mon, 04 August 2014 06:51

I agree to a point. You need to see what the Azure GVWR is to compare. Everyone builds in a safety factor and my evaluation is more or less at sea
level not altitude. Regardless, let's not make that the issue if there even is one. I think as a bunch of us spend more time with these pumps, we'll
get a better idea of what we can realistically expect.

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Bob de Kruyff]

""My understanding (so far) is that the pump was originally intended to be the SOLE source of vacuum for the Azure. For our GMCs, is not its use
intended as an emergency back up in case of engine vacuum failure? During "normal" operation our coaches, it would seem to me that the actual time of
pump operation should be quite minimal and pump lifespan should probably outlast our coaches. Pump "turn-on" pressure should likely be set at several
PSI under the vacuum normally provided by a running engine which would minimize run time. ""

That really is the bottom line.

--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Kerry Pinkerton]

And it certainly sucks more than a JC-4 8o

--
Kerry Pinkerton

North Alabama, near Huntsville,

77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76 Eleganza to be re-bodied as an Art Deco car hauler