[GMCnet] DOT 5.1 Brake Fluid

[RJW via Gmclist]

A couple of years ago, I was en-route in our GMC from Reno, NV (attended a wedding there) back home to Troy, MI via Albuquerque, NM. To add fun and
excitement to the return trip I decided it would be fun to drive through Death Valley as I had never been there. It was April after all and the young
lady at the visitor's center near Lone Pine, California suggested that the drive in a RV would be no trouble in April as trucks do it all the time.

Well the trip down into the valley was way more fun and excitement than I had anticipated. SHE wants no part of that kind of fun in any future trips.


Upon leveling off near sea level the Tire Pressure Monitoring system stated to beep indicating an overheat on the front 2 tires. At the same time I
started to lose quite a bit of braking. Good thing we were level and we had a place to pull over and stop. I got out and found that the newly
installed 80MM calipers were hot enough to smoke. So I figured the DOT 3 brake fluid had been at or near the fluid's boiling point. After I let
things cool, we had normal braking. The rest of the drive through the valley was no problem with brakes but I did have issues with fuel vapor and
ignition that I could describe in a later post. But we did make it back home OK.

During a visit to Dave Lenzi last week to pick up some more parts (his basement is like Disney Land), we discussed my lack of brakes on that trip. He
suggested among other things that I might want to consider DOT 5.1 fluid as it has much higher boiling temperatures than the DOT 3 I had in my system
and was compatible with both DOT 3 and DOT 4 unlike DOT 5.

I am wondering if anyone has an opinion on going to DOT 5.1

Thanks


--
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com


Coop Roller Cam 455, Howell TBI + EBL, 3.42 FD, Quadra Bag, Macerator, Lenzi stuff, Manny Tranny etc.


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[Johnny Bridges via Gmclist]

How clean of type 3 does the system have to be to put 5.1 in? Is it (5.1) compatible with the o - rings and seals in the coach? It seems the time to
use it would be when you replace the cylinders and calipers... you'd have to remove them to get all the existing fluid out anyway, or turn the coach
upside down to drain them :)

--johnny
--
Foolish Carriage, 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

[John R. Lebetski via Gmclist]

1) if you are boiling DOT 3 you have bad driving habits. You will also cook the grease and glaze linings.

2) silicone based fluids love to leak past seals in my experience.
--
John Lebetski
Woodstock, IL
77 Eleganza II

[Dave King via Gmclist]

Remeber, 5.1 is absolutely compatible with DOT 3
For some reason. "they" decided to make the latest version
Of conventional brake fluid 5.1


--
DAVE KING
lurker, wannabe
Toronto, Ontario, Canada

[Mike Kelley via Gmclist]

Johnny B.:
Can you schedule this when I can attend - I want to see that coach upside down!
Mike/The Corvair a holic

Sent from my iPhone

[James Hupy via Gmclist]

GM recommends D.O.T. 3. What you experienced in Death Valley was what we
call Extreme Service. IF your brake fluid was fresh and contained
absolutely NO WATER OR OTHER CONTAMINANTS, when things cooled down, you
should have been fine to continue to use your coach normally. Proceed
downgrade in the same gear that you would climb it. Use the brakes
intermittently, and give them time to dissipate heat between
applications. If you "ride the pedal" continously on downgrades, be
prepared to glaze the drums and rotors unless you use aggressive type
linings like ceramic or semi- metallic or full metallic ones. 12,000 pound
vehicles require driving like a truck. Lots of following distance. Frequent
rest breaks are a really good idea, as well.
Jim Hupy
Salem, Oregon

[Scott Nutter via Gmclist]

Emery had a good post about the 5.1 brake fluid about a year ago. I believe he went with the Wagner brand. There was a lot of good info in the posts.
Scott.
--
Scott Nutter
1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, tankless water heater, everything Lenzi. Alex Ferrera
installed MSD Atomic EFI
Houston, Texas

[Todd Sullivan via Gmclist]

5.1 is compatible with dot 3. That means you can have some dot 3 left in
your system with no issues (other than the 3 portion may boil). I switched
my front brake system on my off road bike to 5.1 and that resolved all of
the brake fade conditions I encountered prior.

Sully
Bellevue wa

[RJW via Gmclist]

JohnL455 wrote on Thu, 13 February 2020 16:17

> 1) if you are boiling DOT 3 you have bad driving habits. You will also cook the grease and glaze linings.
>
> 2) silicone based fluids love to leak past seals in my experience.

Have you ever driven down to Death Valley from California in a GMC? I think I have good driving habits thank you. I don't ride the brakes and try to
give them time to cool between brake applications.

--
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com


Coop Roller Cam 455, Howell TBI + EBL, 3.42 FD, Quadra Bag, Macerator, Lenzi stuff, Manny Tranny etc.

[James Hupy via Gmclist]

Yes, I have driven that exact road. In my GMC. Pulling a trailer. And I
never overheated my brakes. And I have a 1978 Royale. A heavy coach. But, I
have a couple of upgrades that perhaps you do not. 80 MM front Calipers
with Sticky Ceramic lining, and I have different diameter wheel hydraulic
cylinders, which prevents rear wheel lockup. And I use semi-metalic premium
riveted linings. They are noisy, and grabby when they haven't been used
for a while, but they stop the coach very well.
That is about the best that stock brakes can be without reaction arms
and 6 wheel disc brakes. That drop into death Valley is a fair test on
whether your brakes need attention. But, there are much worse hills than
that.
One that comes to mind is is British Columbia, Canada. Near Whistler
Ski resort. 23 miles of continuous downhill and an 18% grade. I did not
stutter. 18%. The most severe test I personally have encountered. We
traveled that one as a group. At least 7 GMCs. Some towing, some not.
Every coaches brakes were smoking, including mine. A butt-puckering
adventure for sure. These coaches were state of the art, 40 years ago. Not
by today's standards.
Jim Hupy
Salem, Oregon

On Thu, Feb 13, 2020, 2:33 PM RJW via Gmclist <gmc...@list.gmcnet.org>
wrote:

[Emery Stora via Gmclist]

You do not have to change out any parts. 5.1 is not a silicone fluid. It is a glycol based so it it compatible with Dot 3 or Dot 4 fluids. I just sucked out my master cylinder and added 5.1 and then bled the brakes until they run clean.

It is compatible with the rings and seals.
A very simple thing to replace your existing fluid with 5.1 and I highly recommend it.
They found out how to raise the boiling point by the addition of low amounts of borates.

Emery Stora
77 Kingsley
Frederick, CO

> On Feb 13, 2020, at 2:15 PM, Johnny Bridges via Gmclist <gmc...@list.gmcnet.org> wrote:
>
> How clean of type 3 does the system have to be to put 5.1 in? Is it (5.1) compatible with the o - rings and seals in the coach? It seems the time to

[Emery Stora via Gmclist]

[RJW via Gmclist]

James Hupy wrote on Thu, 13 February 2020 18:00

> Yes, I have driven that exact road. In my GMC. Pulling a trailer. And I
> never overheated my brakes. And I have a 1978 Royale. A heavy coach. But, I
> have a couple of upgrades that perhaps you do not. 80 MM front Calipers
> with Sticky Ceramic lining, and I have different diameter wheel hydraulic
> cylinders, which prevents rear wheel lockup. And I use semi-metalic premium
> riveted linings. They are noisy, and grabby when they haven't been used
> for a while, but they stop the coach very well.
> That is about the best that stock brakes can be without reaction arms
> and 6 wheel disc brakes. That drop into death Valley is a fair test on
> whether your brakes need attention. But, there are much worse hills than
> that.
>

> Jim Hupy
> Salem, Oregon

That trip down to Death Valley was a wake up call that my brakes needed attention. It is apparent that 80MM calipers with stock drum (probably not
optimally adjusted) brakes in an over weight vehicle is not enough for dealing with the significant downhill grades often seen in the western US.
That is the main reason that I had a visit to see Dave Lenzi who knows more about brakes than I do.

My question was not about how bad my brakes are, or to be ridiculed about my ability to drive a GMC in the mountains.

I was asking about about DOT 5.1 to help me make an informed decision on whether to I switch to that during my brake system rebuild.

[Emery Stora via Gmclist]

Yes, GM recommended Dot 3 but only because Dot 5.1 did not exist at the time.
Brake fluids change for the better from time to time as labs develop fluids with better characteristics, just as Oils and Transmission fluids have changed.

I highly recommend change your GMC over to DOT 5.1.

Emery Stora
77 Kingsley
Frederick, CO

[Emery Stora via Gmclist]

John
DOT 5.1 IS NOT A SILICONE FLUID.

DOT 5 is silicone but DOT5.1 is a glycol based fluid and it totally compatible with DOT 2, 3, 4 but NOT with DOt 5.0.

I don’t know why the SAE or DOT names it with a 5 as it is confusing to some (many) people.

Emery Stora
77 Kingsley
Frederick, CO

[Ken Burton via Gmclist]

Look at this chart and decide what you want to use. I have used DOT 4 in everything from my motorcycles to every on road vehicle own or work on. I
have never tried DOT 5.1 . The numbers in this chart are the minimum boiling points required to meet the DOT standard.

Dry boiling point is what you get out of the can.

Wet boiling point is what you get after the fluid is installed for a couple of years and has absorbed some moisture out of the air.

I suggest that you want the best (highest) wet boiling point that you can find.

I have a cheapy tester (under $10.00) that you can stick in your reservoir and measure the amount of that you fluid has absorbed.

https://epicbleedsolutions.com/blogs/faq/whats-the-difference-between-dot-4-and-dot-5-1-brake-fluid#
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[James Hupy via Gmclist]

I am sorry and apologize to you if you feel insulted by my comments about
"riding the brakes, etc. I assure you that my intention was not to insult
or demean you in any way. We encounter many people here on the net. Some
are novices, with absolutely no experience driving heavy vehicles down
steep grades, and some are more knowledgeable than that. I have no way to
determine which category every person fits into, so I rely upon giving too
much information just to make sure I cover all the bases. Again, sorry if I
hurt your feelings.
Jim Hupy
Salem, Oregon

[Robert Edwin Broadwell via Gmclist]

Mr H :p

You never insult any of us with your posts and I for one always look forward
to reading them.

I had the same thing happen to me on my 26ft when I came thru Death Valley one time
and as it has a Manny 1-Ton up front I suspect brake fluid also. Never had another
problem like that since and have put another 10,000 miles on it-guess I should change
over to DOT 5.1 or the new EIS 6 that I just used in my 23ft.

When I put the new master cylinder on my 23 ft last year I used Wagner DOT 5.1 at
$13 per Qt. Was looking for some again this past week the the price is up to
$25 per Qt. That is when I found the Bosch EIS 6 that is supposed to be 10%
better than 5.1 for 13 per Qt so I have switched over to that for now.

Yes I have wondered too why they went with 5.1 instead of 6 as it is easy to get confused
with the 5.0 and 5.1 designations and the two are not compatible.

Regards,
Bob
--
Bob Broadwell
75 Eleganza II-Rebuilt performance engine, Manny trans, Manny 1-ton front end, 73 23ft with a side bath getting some updates-both living in Las Vegas

[Ken Burton via Gmclist]

Ken Burton wrote on Thu, 13 February 2020 18:12

> Look at this chart and decide what you want to use. I have used DOT 4 in everything from my motorcycles to every on road vehicle own or work on.
> I have never tried DOT 5.1 . The numbers in this chart are the minimum boiling points required to meet the DOT standard.
>
> Dry boiling point is what you get out of the can.
>
> Wet boiling point is what you get after the fluid is installed for a couple of years and has absorbed some moisture out of the air.
>
> I suggest that you want the best (highest) wet boiling point that you can find.
>
> I have a cheapy tester (under $10.00) that you can stick in your reservoir and measure the amount of that you fluid has absorbed.
>
> https://epicbleedsolutions.com/blogs/faq/whats-the-difference-between-dot-4-and-dot-5-1-brake-fluid#

OK, I made you a little chart and added in some other options/ brands. For you emailers I have no control on how the columns line up, so I made the
chart with the temps first followed by the type / brands in an attempt to keep the columns readable for you.

Dry(f) Wet(f) Type or brand
401 284 DOT 3
446 311 DOT 4
506 321 Valvoline DOT 4
509 338 Motorcraft DOT 4 Low Viscosity
518 374 DOT 5.1
536 388 ATE type 200 (blue or amber)

What you are interested in is the wet boiling point number and ATE is still the winner there. It should be cheaper than DOT 5.1 .

My thoughts on the subject is you should never be getting the fluid as hot as the dry boiling point of DOT 3. So if the moisture is measured at least
once a year, then you will know when to change fluid. A higher boiling point fluid will not hurt but keeping it dry, testing it occasionally, and
using the brakes sparingly should eliminate your problem.

https://www.amazon.com/ITEQ-Liquid-Tester-Indicators-Calibrated/dp/B076SC377J/ref=pd_sbs_263_t_0/144-1267831-6760043?_encoding=UTF8&pd_rd_i=B076SC377J&pd_rd_r=eab66d98-ecb6-4ad7-b83e-77d602e1b52a&pd_rd_w=wcyNM&pd_rd_wg=5uXUf&pf_rd_p=5cfcfe89-300f-47d2-b1ad-a4e27203a02a&pf_rd_r=3457G2X6SG8DKQTY886S&psc=1&refRID=3457G2X6SG8DKQTY886S

https://www.ebay.com/itm/Brake-Fluid-Tester-5-LED-Car-Vehicle-Auto-Automotive-Testing-Tool-For-DOT3-DOT4/262023966485?epid=1763134336&hash=item3d01d86f15:g:4KYAAOSwozRZyLLi

[Larry via Gmclist]

Ken Burton wrote on Sat, 15 February 2020 00:46

Thanks for this Ken. Just a FYI. It should be noted about the ATE Super Blue that "It has been determined that ATE Super Blue does not comply with the
applicable US DOT Federal Motor Vehicle Safety Standard for brake fluid, due purely to blue-tint for the color. The federal standard requires motor
vehicle brake fluid to be colorless or amber in color and distribution of super "blue" has been suspended. However, the same Fluid with out the Blue
tint continues to be available!"
The ATE is available in Amber. I've been using this for years and switch it off with the "Valvoline DOT 4". A little harder to see the Amber come
through than it was the Blue, but still works. Blue is available IF you want to get it shipped from the UK, but is technically illegal to use in US.
JWID
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.

[Jim Kanomata via Gmclist]

It is great to know about the better fluids, but if your running OLD fluid
your having issue with moisture.
Yes water that turns into steam at much lower temp.
Steam is like gas and it will behave that way.
Flush out the old fluid and problem will be solved unless you ride your
brakes.
This issue and proper method of driving going down long hills were big
topic back in 1985.
I’m familiar with Death Valley and most automotive manufactures test brakes
and other components in that area and spend days there.

On Sat, Feb 15, 2020 at 4:59 AM Larry via Gmclist <gmc...@list.gmcnet.org>
wrote:

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

[Ken Burton via Gmclist]

I have been told that ATE blue is available in Canada but never tried to verify this. I have some around here so I have not tried to buy any more. I
have used DOT 4 for years but did put ATE in my GMC. I need to go test it some time soon for moisture. I think I forgot to test it last year.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Les Burt via Gmclist]

ATE Super blue brake fluid is still available in the USA and Canada. It isn’t as readily available, but it’s still out there and can be purchased for $18-20 a litre. It’s just being sold as a motor sports or off-road only product.

Les Burt
Montreal
'75 Eleganza 26'

> On Feb 16, 2020, at 4:13 AM, Ken Burton via Gmclist <gmc...@list.gmcnet.org> wrote:
>
> I have been told that ATE blue is available in Canada but never tried to verify this. I have some around here so I have not tried to buy any more. I

[John R. Lebetski via Gmclist]

Looking up Mobile One grease specs, max operating temp is 302F so all but DOT3 will destroy your bearing grease. Remember that the wheel cylinders or
caliper are one step removed from the friction material or drum/disc so expect hub temps to track pretty close with brake fluid temps.

--
John Lebetski
Woodstock, IL
77 Eleganza II

[Emery Stora via Gmclist]

John
that is a strange way of looking at it. Just because a can of brake fluid says it has a boiling point of, say, 500 deg F does not mean that it will run at 500 deg F.
If it get to 500 deg F with DOT 3 brake fluid the fluid will boil away and your brake parts will still get to 500 deg F or higher. The DOT 3 does not limit the temperature of your parts, bearings etc.,
So, how can you say al but DOT 3 braked fluid will destroy your bearing grease? If your bearings get over 302 Deg F (say 500 DEG F,) even DOT 3 will have boiled out and you would still destroy your bearing grease.

Emery Stora

> On Feb 16, 2020, at 10:45 AM, John R. Lebetski via Gmclist <gmc...@list.gmcnet.org> wrote:
>
> Looking up Mobile One grease specs, max operating temp is 302F so all but DOT3 will destroy your bearing grease. Remember that the wheel cylinders or

> caliper are one step removed from the friction materialor drum/disc so expect hub temps to track pretty close with brake fluid temps.

[Emery Stora via Gmclist]

> On Feb 16, 2020, at 10:45 AM, John R. Lebetski via Gmclist <gmc...@list.gmcnet.org> wrote:
>

[John R. Lebetski via Gmclist]

The synthetic hub grease is compromised above 302F. If the DOT3 boils below that, then you get brake fade that limits further temp rise. Sure you
may crash, but your grease will not fail, causing not too distant future "unexplained " bearing failure with jettison of wheel assemblies etc. The
DOT3 acts as the fusible link in the system. Better practice is to not heat drums and discs into that operating range. I guess my point is in a
balanced system, adding performance in one area can put greater demands on other parts of the system that aren't alway accounted for.

[Ken Burton via Gmclist]

6cuda6 wrote on Sun, 16 February 2020 07:48
> Ken is the ATE product line blendable with other brands or does the brake system need to be flushed?

ATE TYP 200 amber or blue is DOT 3 and DOT 4 compatible. No flushing is required. Just empty the master cylinder with a baster, refill with ATE TYP
200, and start bleeding until the fluid coming out changes color.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana