[GMCnet] new owner questions

[Joe williams]

Hello all, I just purchased my first GMC last week. 1978 Royale rear twin and had a good trip back to Iowa from Wyoming (850 mi) with no issues. So
now I have been going over everything and have found a few things that need attention and would appreciate any advice all you experts can give me.
the first is I have a split cv boot on the drivers side, cv joint not making any noise yet.
Is it best to R & R it with a rebuilt axle or try to remove old boot and replace with new boot.
How time consuming and challenging is this job for a newbie?
I see that some have used the split boot option with good and bad results.any opinions on this?
question #2 - It has a 4 bag rear suspension, Leigh Harrison 1999 (I think) and the bag pressure is 110 psi on the driver side and 100 psi on the
pass. side. does this sound normal for this system? it seems high to me, and do you adjust the pressure at the air compressor? it's at 112 psi

any info is greatly appreciated.
thanks, Joe

--
jwilly
1978 Royale rear twin

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[Jim Kanomata]

Joe,
Depending on the milage on the coach, one might just replace the boot.
Two piece is ok, but I suggest a one piece.
Give me a so we can discuss.
On the Harrison system,it does require high pressure, just set the height
correctly.
I can also give you that info.

--
Jim Kanomata
Applied/GMC, Newark,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502

[Jon Roche]

Welcome.

I dont believe you need to replace the axle. You should be just fine installing a new boot. Like you said there are
Both success
Stories and failures of split boots, but I have also had my own failures of non-split boots.

The job itself is messy, but not at all impossible. I have done a few, and I just remove tire/rim and axle nut, pop the tie rod off the knuckle and
I can muscle the outer cv ut and over to be able to install a boot. It takes some muscle to flex it to come out, but do-able. I personally have
only installed non-split boots and I like the dorman one now. Have had failures on some others, but the dorman one has been good now for 3-4 years.


I know a few that have a year or two and longer on some dorman split boot as well.

I do not know about your airbag system, but coach is heavier on driver side due to onan generator, so i am just guessing it is normal pressures.


--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/

[Billy Massey]

Hi Joe
Welcome to the family.
Just replace the boot and add more grease. Jim will sell you what you need.
Call him at 800 752 7502. www.appliedgmc.com

The rear air springs are to control the ride height. Pressure doesn't matter
much.

bdub

76 Palm Beach in Central Texas
www.bdub.net/GMCLinks.html
www.gmcmotorhomemarketplace.com
https://www.facebook.com/groups/classicgmcmotorhomes/
https://www.facebook.com/groups/gmcmm/

GMCnet email list - http://www.gmcnet.org/
GMCnet forum mirror http://gmc.mybirdfeeder.net/GMCforum/

-----Original Message-----
From: Gmclist] On Behalf Of Joe williams
Sent: Friday, July 7, 2017 11:34 AM
Hello all, I just purchased my first GMC last week. 1978 Royale rear twin and
had a good trip back to Iowa from Wyoming (850 mi) with no issues. So now I have
been going over everything and have found a few things that need attention and
would appreciate any advice all you experts can give me.
the first is I have a split cv boot on the drivers side, cv joint not making any
noise yet.
Is it best to R & R it with a rebuilt axle or try to remove old boot and replace
with new boot.
How time consuming and challenging is this job for a newbie?
I see that some have used the split boot option with good and bad results.any
opinions on this?
question #2 - It has a 4 bag rear suspension, Leigh Harrison 1999 (I think) and
the bag pressure is 110 psi on the driver side and 100 psi on the pass. side.
does this sound normal for this system? it seems high to me, and do you adjust
the pressure at the air compressor? it's at 112 psi

[Emery Stora]

I would suggest raising the pressure a bit — perhaps 120 to 130 psi. This will allow the bags to raise higher when leveling at a campsite and allow the system to fill the bags slightly faster.
Most single OEM bag systems are around 90 psi for ride height but I think I read once that the Harrison system needs more pressure to level the GMC.

Emery Stora
77 Kingsley
Frederick, CO

[Matt Colie]

Joe,

Welcome to the group, family, cult, asylum.....

A friend that sometimes writes here is now running 2 split boots. He has not been able to use the coach as much as he might have liked, but the boots
have not been an issue. They are bags easier to get on than the usual boot, but it is still a mess. He did do one without even getting the axle
clear of the hub. I would say that if you want to put on a usual boot, it is worth your while (including new screws and Loktite) to get the drive
axle out where you can wrestle with it standing up.

After having cars with axle boots for about 40 years, I can say that taking care of it sooner beats buying a replacement joint.

You have already found the value of this community, and that puts you out ahead of many new owners. I would like to ask you to add your location to
your sigfile. This forum started out as a e-mail list and many still read it that way, so they don't see the header where your location is
published.

About this community, it is like few others. I have seen it rally to aid of an owner more times than I can count (yours truly is included there), and
it is a thing of beauty. The only other community that I know of like this is that of the watermen that are my world. For this reason, I like to
welcome new owners much as a new owner or vessel is welcomed there. So,

May the Good Lord bless this coach and all those that set forth within her.

Welcome Joe

Matt

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

[Jim Kanomata]

The pressure is one of the main reason Jim Bounds of Coop Mtrs consulted
with us to come up with a system that would give same control performance
in the rear suspension and have lower air pressure requirement.
Tha is when we developed the Quadra Bag System that stabilizes the rear and
run on 80-85 psi .

--

Jim Kanomata
Applied/GMC, Newark,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502

[James Hupy]

Anything over 100 psi is not advised by either Firestone or the
manufacturer of the 72000 controller. They are both adamant in their
opposition to higher pressures and limit their remote controllers to
100psi. I have been in contact with both of them and requested that they
allow me to reprogram their systems to allow higher pressures. Both refused
to do so. As Firestone makes the bags, they probably know the safe high
limits. On single bag systems, you can add extenders to the bogie that
lowers the pressure quite a bit, that will get the system to full
extension. I don't know why you would need it to pump any more air than
that. I suspect it might be the old horsepower thing."You can never have
too much money, a girlfriend too pretty, or too much horsepower". Same
applies to air pressure, I suspect.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

[Emery Stora]

Well, I've owned my motorhome for 36 years now and the air tank pressure has been set at 130 psi most of that time.
When traveling the bags are at approximately 90 psi.
When parking on a non-level campsite they have occasionally been pumped up as high as 130. No adverse effects. The original bags lasted for over thirty years.
You say you don't know why anyone would need over 100 psi. You might consider being able to level it better at a campsite as a reason.

By the way take a look at the GMC Maintenance manual X7725. Page 4A9-4A10 says the compressor will shut off at 120 psi. Also on page 4A10 in the paragraph PRESSURE SWITCH it says " The air pressure switch is designed to maintain air pressure in the wet tank between 100 and 120 psi. Switch activates at 100 psi and opens at 120 psi.
You might want to go back to Firestone and your manufacturer of the 72000 controller and point out to them that GM used 120 psi in the bags, NOT 100 psi.

Emery Stora
77 Kingsley
Frederick, CO

[Keith V]

I would bet a dollar of James' money that the limit Firestone is worried about is not the bags, but the internal valves. Especially since they really don't know what bags we are running.

That and they don't want to deal with managing a new sku for relatively low volumes. I'm sure if you put in an order for 1,000,000 you'd get your change.

________________________________
From: Gmclist <gmclist...@list.gmcnet.org> on behalf of Emery Stora <emery...@mac.com>
Sent: Friday, July 7, 2017 2:24:41 PM
To: gmc...@list.gmcnet.org
Subject: Re: [GMCnet] new owner questions

[James Hupy]

Emery, you missed my point. I said, "When the suspension reaches the
maximum travel, then you can put 500 psi in there. It will not go any
higher." If you feel you want to run higher pressure than that, go with
your feelings. Just don't air them up when I am in the vicinity. I hate
sudden loud noises. (Grin)
Jim Hupy

[Jim Kanomata]

Lee Harrison ran his Firestone bags over 120 psi and never heard of
problems. As long as it is around 5-6 years old, they seem to withstand the
higher pressure just like the tires.

[gene Fisher]

On Fri, Jul 7, 2017 at 9:34 AM Joe williams <jwi...@netins.net> wrote:

> Hello all, I just purchased my first GMC last week. 1978 Royale rear twin
> and had a good trip back to Iowa from Wyoming (850 mi) with no issues. So
> now I have been going over everything and have found a few things that
> need attention and would appreciate any advice all you experts can give me.
> the first is I have a split cv boot on the drivers side, cv joint not
> making any noise yet.
> Is it best to R & R it with a rebuilt axle or try to remove old boot and
> replace with new boot.
> How time consuming and challenging is this job for a newbie?

Read here
http://gmcmotorhome.info/front.html#boot

> I see that some have used the split boot option with good and bad
> results.any opinions on this?
> question #2 - It has a 4 bag rear suspension, Leigh Harrison 1999 (I
> think) and the bag pressure is 110 psi on the driver side and 100 psi on the
> pass. side. does this sound normal for this system? it seems high to me,
> and do you adjust the pressure at the air compressor? it's at 112 psi
>
> any info is greatly appreciated.
> thanks, Joe
>
> --
> jwilly
> 1978 Royale rear twin
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
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

[Thomas Phipps]

1. Pressure in your Leigh Harrison bags is very close to the pressure in my Leigh Harrison bag system. Measure your ride height to be sure that the
air pressure is correct for your coach. This system has been on my 1975 Avion 26' for 4 years without any problems. Just check your ride height before
you leave home.
2. I have 2 of the Dorman split bags on my outer CV joints. At least one has been in place for 3 years. A very fast and easy replacement. Having
wrestled with the Dorman 'Universal boot' and Dorman split boot, the split boot fits better around the big edge of the outer CV joint. I carry one as
a spare. I, and many others, have used the split boot on the CV joints of many VW and Porsche products. Lots of years on those vehicles.
3. I believe that your air pressure switch is mal-adjusted. The switch should turn on the air compressor at 100psi and turn off at 120 psi. There is a
user adjustable screw inside the cover to move the air range.

Enjoy your new toy. Many happy miles. Get a copy of the "Black List," and keep it in the coach.
Tom, MS II

--
1975 GMC Avion
KA4CSG

[Ken Henderson]

Welcome aboard, Joe. You've found the right place for technical support.
You'll get a lot of advice, some good, some bad, but at least you'll have
information as a basis to make your own decisions.

I personally have never used a split boot, nor do I think I would. But, if
I did, the one inviolable rule I'd follow, as I do with regular boots, is
to be sure the surface where the large end of the CV joint, where boot
fits, is absolutely clean -- NO grease residue. Same for the inside of the
boot there. That ensures that when you install the clamp, there' s a good
seal, with no boot sliding.

It's also important, IMHO, to use only double-wrap clamps. At one time
NAPA sold those clamps pre-cut; whether they still do I don't know. I buy
the "buckles" and 1/4" Band-It from McMaster-Carr and cut my own -- 37" for
the large end clamp. The small end clamp is not needed, but if it makes
you feel better, re-use a large end Band-It clamp (IF you have one).

I've had the Harrison 4-bag since 1998, with never a problem. I'm still
running the original bags after 100,000+ miles. IIRC, Leigh's
documentations specified 130 psi max. Your settings sound very
reasonable. In case you haven't heard, that system does reduce the maximum
suspension travel vs the OEM system, by about 3", IIRC.

Most Harrison systems I've seen installed follow Leigh's instructions and
mount the manifolds, with their shutoff valves and pressure gauges in the
wheel wells, often on the bag support pedestal. That, IMHO, is a BAD idea,
especially if you have the "fender skirts". Why? Because if the bags are
down, it will be impossible to get to the manifold to add air without
jacking the coach up. I moved my manifolds into the rear compartments,
right at the top of the openings where they're out of the way but easily
accessible. Possibly an added benefit is that if I ever over-inflate a bag
to failure, I won't be beside it.

JWID,

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

On Fri, Jul 7, 2017 at 12:33 PM, Joe williams <jwi...@netins.net> wrote:

> ​...

>
> the first is I have a split cv boot on the drivers side, cv joint not
> making any noise yet.
> Is it best to R & R it with a rebuilt axle or try to remove old boot and
> replace with new boot.
> How time consuming and challenging is this job for a newbie?
> I see that some have used the split boot option with good and bad
> results.any opinions on this?
>

> question #2 - It has a 4 bag rear suspension, Leigh Harrison 1999 (I
> think) and the bag pressure is 110 psi on the driver side and 100 psi on the
> pass. side. does this sound normal for this system? it seems high to me,
> and do you adjust the pressure at the air compressor? it's at 112 psi
>

[Jeanette Hodges]

Midwest Classics group is having a rally at Duluth MN starting Sunday. Many have Royales there. It would be worth your while to get there by car or motorhome to see n ask questions of lots of good people. If you want info google Midwest Classics GMC.

Sent from my iPhone

[Jeanette Hodges]

Kim Weeks administrator for GMC Motorhomes International is in Indanola Iowa for summer. Lots of info there. Gmcmi.com

Sent from my iPhone

[Emery Stora]

I am thinking perhaps you are missing my point. You said that you don’t know why anyone would want more than 100 psi.
I was pointing out that GM used a cut off pressure of 120 psi over 40 years ago.
They are not going to blow up at 120 or 130 psi.

Emery Stora

[Joe williams]

WOW! Thanks to all for your advice/opinions, didn't think I would get such a great response, I think I'll just go with a split boot for now since it
sounds the easiest/fastest and I can get her back on the road. if it doesn't hold up I can redo it later.

Ken, what is a double wrap clamp? do I need to get a special tool to use them?

Tom, I found on one of your old posts that you used Dorman 03609 ,did you use the clamps that came with it?

and do you know what bag is used on the Harrison system and where I can get a spare to keep in the coach.

Thanks again to all, so great to be able to get such good advice so quickly and look forward to meeting some of you at a rally soon.

Joe


--
Joe Williams

[Rob Mueller]

Joe,

Firestone P/N W01-358-3400 - with bellows #224C
Compressed height: 3.00 inches
Extended height: 8.91 inches
Range: 5.91 inches

http://firestoneip.com/-/media/www/global/files/documents/Data%20Sheets/W013583400.pdf

http://www.sdtrucksprings.com/index.php?main_page=product_info&products_id=8195

Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist...@list.gmcnet.org] On Behalf Of Joe williams
Sent: Saturday, July 8, 2017 11:20 PM
To: gmc...@list.gmcnet.org
Subject: Re: [GMCnet] new owner questions

[Jim Kanomata]

We stock the bags for all as people need hem in a rush. Contrary to belief
, there are too many configurations of same style.
When you get a chance to visit our web site, you'll realize were not a
hobby shop.
We have 3 people that handle tech support as well.

--
Jim Kanomata
Applied/GMC, Newark,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502

[Ken Henderson]

Joe,

Double-wrap clamps do require a special tool, which can be had for <$15 or
>$150. The simplest, cheapest one is fine. They're really just a simple
strip of 1/4" wide stainless steel with a special buckle to secure the
ends. When installed, the inner loop of SS provides a low-friction surface
for the outer loop to slide on as the band is tightened. That causes the
securing force to be applied perpendicular to the rubber, preventing
"puckering". Ordinary single-wrap clamps tend to move the rubber parallel
to the clamp, causing it to bunch up and create leakage-ways. Also, the
buckles are very low profile so there's less danger of them striking fixed
objects.

If you have to buy bulk band and buckles, it's a little expensive, but
you'll find a lot of uses for them besides CV boots, making the average
cost per use very reasonable. Here's my source:

https://www.mcmaster.com/#hose-banding/=18erplk

Band: 5422K53
Buckles: 5422K67
Tool: http://www.lislecorp.com/divisions/products/?product=164
​or: https://www.napaonline.com/p/SER30950​ (you may have to search for
that PN)

NAPA used to carry #3415 for the small clamp and 3416 for the large on, or
3401 for a 10-clamp kit. I no longer find those on line.

If you're forced to use one of the more popular "squeeze to lock"
single-wrap clamps, I'd recommend lubricating the inside of the clamp to
minimize puckering.

Ken H.

On Sat, Jul 8, 2017 at 9:20 AM, Joe williams <jwi...@netins.net> wrote:

> ​...

>
> Ken, what is a double wrap clamp? do I need to get a special tool to use
> them?
>

​...​

[Bruce Hart]

Ken
Put a UJ in front of the clamp number. Last fall I bought a box of 10 from
my Napa Store.
Now try to find an inner cv boot for the drive shaft.
UJ3416
UJ3415
https://www.napaonline.com/en/p/UJQUJ3416

On Sat, Jul 8, 2017 at 11:07 AM, Ken Henderson <hend...@bellsouth.net>
wrote:

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class

[Ken Henderson]

By golly, that worked. Wonder why they don't give any specifications other
than "1/4" wide"?

Ken H.

On Sat, Jul 8, 2017 at 2:17 PM, Bruce Hart <hart...@gmail.com> wrote:

> Ken
> Put a UJ in front of the clamp number. Last fall I bought a box of 10 from
> my Napa Store.
> Now try to find an inner cv boot for the drive shaft.
> UJ3416
> UJ3415
> https://www.napaonline.com/en/p/UJQUJ3416
>
> On Sat, Jul 8, 2017 at 11:07 AM, Ken Henderson <hend...@bellsouth.net>
> wrote:

> ​...

> > NAPA used to carry #3415 for the small clamp and 3416 for the large on,
> or
> > 3401 for a 10-clamp kit. I no longer find those on line.

[Bruce Hart]

Napa did a redo on their web page and for myself it was a bit hard at first
to navigate.
To find a part I go to Parts and Accessories, this gives a drop down menu
and I select the category, than a sub-category that the part would most
likely be in. Than if I have a part number I will put that into the search
box.

Example, if I want to look up Optima batteries I would click on Parts and
Accessories, than electrical, followed by sub-category batteries. Now I
put Optima in search panel and get the listing of what Optima batteries are
available.

By the way the UJ stands for u-joint. Who would have thought!

On Sat, Jul 8, 2017 at 2:46 PM, Ken Henderson <hend...@bellsouth.net>
wrote:

--

Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class

[Johnny Bridges via Gmclist]

Any time you do a single weight clamp - radiator hose, CV joint, etc.,take a small hammer - soft face if you have one - and tap around the entire
joint while you tighten the clamp. This reduces the tendancy for the rubber to bunch up under the clamp.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

[Rob Mueller]

Good idea!

The Project Apollo Portable Life Support System had beaded end aluminum metal tubing that water and oxygen flowed through. They were
joined together with silicone tube "unions" clamped with stainless steel ratcheting band clamps. To assure the stainless steel
clamps exerted the same force around the entire OD two layers of Teflon tape were wrapped around the silicone rubber tubes.

Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist...@list.gmcnet.org] On Behalf Of Johnny Bridges via Gmclist
Sent: Sunday, July 9, 2017 10:56 PM
To: gmc...@list.gmcnet.org
Cc: Johnny Bridges
Subject: Re: [GMCnet] new owner questions

Any time you do a single weight clamp - radiator hose, CV joint, etc.,take a small hammer - soft face if you have one - and tap
around the entire joint while you tighten the clamp. This reduces the tendancy for the rubber to bunch up under the clamp.

--johnny