Brake Problems

[exrench]

HAWG6 made the statement"lubed the pins annually and still had two lock-ups" This statement is disturbing to me as it suggests that the pins are the only part of the caliper that requires lubrication.In my experience,the pins on the W22 are extremely well protected by the boots and are very greasy and free when removed.There is no evidence that they even need to be lubricated in light of this.Further,it is simply not possible to lube the calipers without removing the wheels.Unscrewing the pins and re-greasing same just will not be effective in preventing pads from dragging.The process is pretty involved and has to include wire wheel treatment on the ends of the pads and a thorough cleaning of the slides where the pads contact them .In addition,the stainless pad found at one end of the pads has to be removed and rust trapped under it also removed.Rust left there will "expand"and push on the end of the pad,causing it to seize and drag.This is the same protocol I have used on my F53 chassis as well as the W22 on a two year schedule.At 36,000 miles no brake issues.

[hawg6]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DriVer:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by hawg6:
Whatever brake system Workhorse installed prior to 2002 and post 2004 appear to not to have the brake lock-up problems the 2002 through 2004 chassis' have. </div></BLOCKQUOTE>hawg6, Your timeline doesn't support the facts in this case. ZOPS brakes were supplied from the onset on the W-Series in 2001 and sunset in early 2003. In year 2003 the ZOHT caliper was introduced and it has been in continued use ever since.

The ZOPS brakes were subject to a recall the 50401-C. Although there are many here who have endured problems with their ZOHT brakes, I am like you waiting to hear what the resolution may be to owner's issues with their brakes which I believe will be forth coming.

About brake fluid, I have learned more about it from search engines and the experience of the owner members here on iRV2. </div></BLOCKQUOTE>I guess we will wait together. Not sure of the timeline, but from the postings, 2002-2004 are the years with the years with the current problems. From the literature in the pin klts it appears the recall was based on changing the trailing pin design, along with the bolt length and thread configuration and this change happened during the 2003 production year? Was there a change in the caliper/piston design?

[edgray]

Originally posted by DriVer:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">If that's the case how about a metal faced phenolic piston? </div></BLOCKQUOTE>
Mike: I'm thinking you already know the answer to your question above. Below is a paste from page 5 of the Bosch manual featured above this forum:

PISTON
The piston, as shown in Figure 5, is cylindrical in shape and is retained within the caliper housing
piston bore. The function of the piston is to react to the applied hydraulic brake fluid pressure by
translating or sliding out of the caliper housing piston bore. It is this translation of the piston out of
the caliper housing that results in pad contact with the rotor. The contact of the pad with the rotor
produces torque and the braking action of the vehicle. The piston is molded and machined from a phenolic material and has a stainless steel cap

And then on page 6 is the following:

The piston seal also aids in retracting the
piston (i.e., pulls the piston back into the housing bore) upon brake release. This retraction allows
clearance for the pads to be pushed back from the rotor.

I often wondered what "force" was responsible for the task of "pulling back" on the piston, because I did not think that just simple elimination of fluid pressure could "cause" the pistons to retract, thus aleviating rotor contact. Now I know...it seems to be the job of the piston SEAL!! I do realize that all disk brakes work on the principle of very close tolerances, and very short distances exist between "applied" and "released" positions. So, I'm wondering, how come nobody here is blaming the poor little seal for all our troubles?

Like many members, I look forward to the day this issue will be resolved by Bosch/Workhorse/NHTSA.
ED

[edgray]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Was there a change in the caliper/piston design? </div></BLOCKQUOTE>
I believe the ZOH-T pins were put in the existing caliper design in place of the ZOPS pins which were recalled. Some may have replaced entire calipers to aquire the ZOH-T pins, but it was not required. ED

[max49]

Driver, I know you got 64000 miles from your first set of brakes. And I know you have said you intend to change the brake fluid and lube the slides every year or maybe 2, but did you change the brake fluid and lube the slides on your first set of brakes that lasted 60,000 miles plus?
I'm sure changing the brake fluid can't hurt but I doubt if it was ever thought about until the brake problem appeared and that was the simplest explanation to date.

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by max49:
Driver, I know you got 64000 miles from your first set of brakes. And I know you have said you intend to change the brake fluid and lube the slides every year or maybe 2, but did you change the brake fluid and lube the slides on your first set of brakes that lasted 60,000 miles plus? </div></BLOCKQUOTE>Max, That's a good question. I could always write what seems to be the most convenient answer however I did change the brake fluid "once" and service the slides in year 2006 and again most recently with the new calipers.

I wish I had been more proactive about changing my fluid however I believe that we have established the fact that changing brake fluid is cheap and it's the best thing one person can do for their motorhome. Now this advice doesn't necessarily come from the Workhorse service manuals. Where ever you care to look, it's obvious that a significant benefit is evident if a person choses to replace their brake fluid frequently. Brake service and maintenance is not easy but it needs to be done properly and frequently. The incentive to do the maintenance is that these things are expensive and the caveat is that it has to be done early in the vehicle ownership.

It's upsetting when we hear that a person who really likes their vehicle accomplishes a maintenance routine as a reaction to a problem. At that point one might want to say that it may be too little too late. If we learn nothing else from all these postings, service your equipment and do so frequently.

I am not dismissing that we are still waiting for a resolution to our collective difficulties with our brakes and we are still waiting for a resolution to be put forward.

I attribute my longevity to movement and being on the go. At what looks like 10,000 miles per year and frequent outings, this is probably the biggest factor that extended the useful service life of my brakes. My brakes continued to operate even after I started scoring my right rear rotor. It's difficult to hear metal on metal on the rear axle unless someone is out there listening. When I recently replaced all my valve stems and rotated my tires, I checked my brakes and I was very concerned and obligated to change my brakes. One other benefit I believe is being able to park on cement as opposed to dirt or sand.

[max49]

Thanks for the reply Driver.

But what the heck does this have to do with the brakes

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">One other benefit I believe is being able to park on cement as opposed to dirt or sand. </div></BLOCKQUOTE>

Oh, I bet you're talking about sand and grit getting into the brakes.
I drive on more dirt roads than most people do with a Cl A. Oh well, so far, so good.

I park my MH on landscape rock, do I have to move it now?

[CJBROWN]

Two things caught my attention here....
Rust under the pad backing - that seems plausable. And second, permanent storage over dirt or concrete, resulting in greater exposure to moisture that contributes to corrosion. If a pad rides too close to the rotor and starts to heat, it's going to feed itself into a seized condition (BTW, it's seized, not ceased!)

Maybe it does make sense to annually pull off the calipers (and BTW, they're not calibers!) and clean everything up, wire-wheel the pads, sand down any glaze on the rotors, and re-grease the slide-pins. And of course, change the fluid. If the fluid is really coming out that bad on these rigs that will certainly contribute to sticky pistons and dragging pads. Once they start to drag they're going to get hot and seize the caliper, glaze the rotor, even crack it if severly overheated.

If the piston are indeed resin with a stainless cap, they are then extremely different in thermal expansion from a steel caliper body. And that could easily contribute to a sticking condition. Remember when aluminum heads first came out on cast iron blocks? Lots of head gasket failures. Remember the Mazda rotary engines and their failed seals on the combustion chambers? These are all examples of new technologies introduced with seal issues and failures, and later refined.

Okay, another question....I was out to look at the reservoir as I have never even looked at it for 4 years and 18K miles. Afterall, aren't truck brakes supposed to last for many thousands of miles? So the top of the tank is just inches from the ceiling of the engine compartment. You can't even peer in there to see the level, and the tank is too opaque to determine the fluid level from the outside. And how are you supposed to get fluid out of, or into it? Turkey baster with a hose extension??? Why didn't they mount that darn thing about 6" lower?

BTW, my d-max has 63K and the pads still have more than 50% of their thickness. What's up with these worn out brakes so early?

I wonder about coach weight too. One of the things I liked about my shorty is that I'm running the same chassis as the 35, 36, even 38' units. I'm about 18K lbs loaded, with about 3500lbs in CCC. Seems to me the very same brakes are used on a W22 or 24 with another 6K lbs, no? Plus their toad? Maybe the brakes just aren't big enough for those bigger coaches? Is there any correlation to coach size/weight and failures? More failures in wetter parts of the country?

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by max49:
Oh, I bet you're talking about sand and grit getting into the brakes. </div></BLOCKQUOTE>Max, No not that at all. The underside of my MH stays mostly dry and is not subject to rising humidity.

[hawg6]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DriVer:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by hawg6:
Whatever brake system Workhorse installed prior to 2002 and post 2004 appear to not to have the brake lock-up problems the 2002 through 2004 chassis' have. </div></BLOCKQUOTE>hawg6, Your timeline doesn't support the facts in this case. ZOPS brakes were supplied from the onset on the W-Series in 2001 and sunset in early 2003. In year 2003 the ZOHT caliper was introduced and it has been in continued use ever since.

The ZOPS brakes were subject to a recall the 50401-C. Although there are many here who have endured problems with their ZOHT brakes, I am like you waiting to hear what the resolution may be to owner's issues with their brakes which I believe will be forth coming.

About brake fluid, I have learned more about it from search engines and the experience of the owner members here on iRV2. </div></BLOCKQUOTE>The instructions which are included in the "Bosch ZOH-T Anchor Plate Kit Installation Procedure" states "Prior to June 3, 2002, the ZOPS caliper mounting guide pins were the same and used a ----", "After June 2,2002, ZOH-T caliper mounting guide pins are different between the leading and trailing anchor plate locations ----". "When servicing the guide pins manufactured prior to June 3,2003 (i.e. the original ZOPS caliper design), it is permissible to use ZOH-T pins and bolts as long as they are changed as a set." There is nothing in this document indicating the actual caliper was changed. Do you know why the pins were changed? The timeline for the pin change and caliper seize seem to agree? What happened after 2004??

[max49]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Max, No not that at all. The underside of my MH stays mostly dry and is not subject to rising humidity. </div></BLOCKQUOTE>

Oh humidity, I remember that when I lived in FL 25 years ago. And I remember how steel used to rust so fast there.
So rust may be contributing to the brakes hanging up? Seems possible, but I have'nt heard too much about it.
We don't have much humidity here, but we get salt, magnesium chloride etc on the roads, thus also on the brakes.

[edgray]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Seems to me the very same brakes are used on a W22 or 24 with another 6K lbs, no? </div></BLOCKQUOTE>
The W-20,21, 22 chassis use a common brake system. The W-24, 25.5 use a different style caliper with 4 pistons and no slide pins. I believe the rotor and pads are bigger, too. ED

[Photog]

Wow. A new post on the old brake topic and in a day we have three pages.

I wonder how long it will take for this one to get to 74 pages?

I hope the problem gets resolved soon. It sure is burning up a lot of time and energy on this forum.

[Richard 34A]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I hope the problem gets resolved soon. It sure is burning up a lot of time and energy on this forum. </div></BLOCKQUOTE>

And brake rotors and calipers too...