'02 P32 WH Brakes getting hot-

[Sightseer 27]

Hi all, a little more trouble with the motorhome, and I was wondering if there is a cure? As the title says, my '02 Winnebago with a P32 chassis has developed a brake problem.
When I visit a friend of mine in the White Mts. of NH it requires me to do a lot of braking on roads with a lot of grade changes. I haven't had a problem on the flat but after 30 min. or so on hilly roads and a fair amount of breaking, the rear brakes over heat, of course stink and smoke. I have done a fair amount of work already, rear calipers and pads- rotors are like new, brake fluid flush this spring and a rather extensive "going over". I am under the GVW (14,800) and the rig is in excellent condition overall.
Internet and forum searches have had mostly confusion over the Bendix recall on the heavier chassis which doesn't apply. I was hoping- well not really -someone has had or seen this before as I'm running out of ideas.
TIA, Gary

[sswilson]

No problems with the front brakes? I am under the impression that the majority of braking is done with the fronts and they usually need replacing before the rear. Do you know if your fronts are working properly and doing their fair share of braking? Maybe they are not working and your rear ones are overworking? Very strange that rears overheat unless they are doing too much or overweight which you say you are not.

[Sightseer 27]

Originally Posted by sswilson

No problems with the front brakes? I am under the impression that the majority of braking is done with the fronts and they usually need replacing before the rear. Do you know if your fronts are working properly and doing their fair share of braking? Maybe they are not working and your rear ones are overworking? Very strange that rears overheat unless they are doing too much or overweight which you say you are not.

Yeah, this is a strange one. I have lifted the MH up and let the rear wheels dangle- then spun by hand then EO (engine off) brakes replied a number of times and no hang up. Then ER (engine running) brakes applied numerous times with both heavy and lite pressure all OK.
For the front, each side was lifted, each wheel was spun and looked good and with the brakes applied, neither front wheel would spin. I have always been under the assumption that the front to rear ratio favored the front doing most of the "real" work and engaging first.
All of these tests where done as it was looking like an "older" brake line had collapsed, in fact I have all five on order. It looks like they will be stock as I would really like to know what's up rather than taking the "replace 'till it's better" approach.
Thanks for the response.
Gary

[mx08453]

Hmmm, have you considered the bendix brake issues? I understand the problem to be related to moisture in the brake fluid. I am not sure where your master cylinder is located, but consider having DW pump the brakes as you bleed the lines until fresh comes out.

[Sightseer 27]

Originally Posted by mx08453

Hmmm, have you considered the bendix brake issues? I understand the problem to be related to moisture in the brake fluid. I am not sure where your master cylinder is located, but consider having DW pump the brakes as you bleed the lines until fresh comes out.

I don't know who made the brakes on this unit, looks like GM. As I mentioned before, I think part of the reason this is difficult to research is the confusion between GVW's. I think it's the next size up 22KGVW? that had the Bendix issue. I did a complete brake flush this spring. The fluid was murky but not real bad- I have seen much worse fluid working fine.
TNX, Gary

[mgscott4]

I think it could be your front flexible brake lines. The inner lining deteriorates and collapses and limits the fluid. There is a history of this problem on P32 chassis's. They may look good but they may be bad on the inside.

[WeatherTodd]

I would be using the transmission more to slow the vehicle on grades and the brakes less. Matter of fact its what I do on my unit all the time, even in town.

[speed racer]

Check to make sure the pedal is returning all the way after you apply the brakes. There has been problems with the pivot on the linkage because it is hard to get to and lube. Not all have fittings on the and if not you should have one installed.

[Sightseer 27]

Originally Posted by mgscott4

I think it could be your front flexible brake lines. The inner lining deteriorates and collapses and limits the fluid. There is a history of this problem on P32 chassis's. They may look good but they may be bad on the inside.

That is where I was heading as, while I have never seen this myself, I have heard of the problems many times. This is why I jacked up the MH and tried to duplicate the problem. The factor I could not duplicate is the heat from the hilly terrain. As many of you know, especially those that work on their own rigs, they were not designed to be worked on
The hilly section has no real spot to bull over to check (loosen a bleeder and watch for excess/trapped pressure to escape not to mention the risk in traffic.
With the 5 lines on the way, I'm thinking of replacing them all and a refill with Dot4 fluid.
You mention a history of this on the P32, do you have more info?
TNX, Gary

[Sightseer 27]

Originally Posted by WeatherTodd

I would be using the transmission more to slow the vehicle on grades and the brakes less. Matter of fact its what I do on my unit all the time, even in town.

I saw this advice in an unrelated thread when a search sent me to a post on the FMCA site. It's no doubt going to help but I would like to see a real cure.
TNX, Gary

[Sightseer 27]

Originally Posted by speed racer

Check to make sure the pedal is returning all the way after you apply the brakes. There has been problems with the pivot on the linkage because it is hard to get to and lube. Not all have fittings on the and if not you should have one installed.

Do you know if this was on the P32 or the lager W22 chassis?
TNX, Gary

[az bound]

The P32 has a bellcrank on the brake linkage which requires lubing. There is none on the W22. There is a kit available for installing a zerk fitting if there is none on the bellcrank.
www.oemys-performance.com/techtips2.html.zerk

[tomwalt]

I had these exact indications on my 1999, 16,500lb P32 chassis - I bled the brakes and fluid looked OK. It was the calipers sticking.
My indications were, after braking in mountains (or city), the rotor temps measured with IR thermometer were BL - 400 degrees, FR 300 degrees and the other tow less than 200 degrees. Last year the BL and FR were 250 to 300 degrees, so it got progressively worse. The brakes also squealed when hot and braking while turning corners - they did not squeal when cool.
Also noted, my brake pedal travel was less than 3 inches (a P32 WH with 4 disc brakes should be 6 inches travel). Brakes worked great - too good to be true.
After disassembly to lube calipers, found the hot brake pads had crystalized. I replaced all 4 calipers/pads and rotors. I might have gotten away with pads and lubing the caliper pins/pistons, but I plan to keep this so replaced everything for under $2,000 ($1200 parts and 700 labor). I could have done this myself, but the rear brakes would have been a real pain.
Let me know if you want more info. OMEY has P/N info for NAPA, I have it for CARQUEST. Brakes are Bendix 4152828, P/N is stamped near bleed screws.

[tomwalt]

I'd stay with DOT3 fluid - if the brake system is working correctly, DOT 3 will do the job.