Technical Report #2 - Bosch Brakes

[DriVer]

WORKHORSE TECHNICAL REPORT
From The Workhorse Technical Team

Note: This is the second in a series of Workhorse Technical Reports with information that Workhorse considers most important in helping motor home owners avoid potential problems and maximize the economy, safety and enjoyment of their driving experience. This particular report addresses a number of RVer questions surrounding a recent Workhorse recall concerning a Bosch brake defect.

What you need to know about
the Workhorse Bosch brake recall

In May 2009 Workhorse mailed an “interim notice” to alert affected Workhorse owners of a defect in certain Bosch brake caliper assemblies used on Workhorse W20, W21 and W22 motor home chassis models. Pending an approved recall remedy for the problem, the interim notice described the authorized interim repair procedure, at no cost to the customer, for those brake problems related to the defect. However, brake repairs related to typical wear and tear or other issues are still the financial responsibility of the customer. As with any recall, misunderstandings about the defect and about who is responsible for what often arise. This article will briefly explain the nature of the problem and how owners and technicians can determine whether a brake problem is related to the defect or not.

Warning signs

The problem is usually noticed as a sudden seizing or locking up of the brakes. It also typically appears in motor homes five years old and older that have not been driven for extended periods of time.

Signs of the problem may include:

• A distinct brake burning smell.
• Having to apply more engine power to overcome an unaccounted for slowing of the vehicle commonly associated with brake drag.
• An ABS light that is continually on.
• Smoke coming from the wheel end.
• A soft or spongy feel when applying the brakes.

Owners of the affected chassis models who experience any of the signs indicated above should have their brakes inspected at an authorized Workhorse service center. The inspection is at their expense; however, if the problem is related to the Bosch defect, Workhorse will provide an interim repair at no cost to the chassis owner.

Caliper assembly at fault

The defect is related to the Bosch 2 X 66 mm brake caliper assembly. Each caliper contains two pistons that are made of a phenolic material that technicians will recognize as similar to Bakelite. If the motor home is not driven for extended periods of time (typically six months or longer), the phenolic material may absorb and retain moisture from the atmosphere, which may result in an increase in the piston diameter. Motor homes operated more frequently are not likely to experience any problem because the heat generated during braking under normal conditions inhibits the absorption and retention of moisture in the phenolic material.

The piston clearances in the caliper are fairly small — the specified clearance of a new phenolic piston is .004 to .008 of an inch. Measurements of certain phenolic pistons taken from motor homes that have been in service for several years have shown an increase in diameter of up to .0035 inches.

The caliper piston is designed for some expansion due to normal heat absorption during braking. During normal operation, the internal piston caliper seal pulls the piston back into the caliper bore when the brakes are released. However, if the phenolic piston expands due to moisture absorption and heat, the seal may not be able to pull the piston back (called “binding”), which may result in the brake pad dragging on the rotor.

This can be hard for a technician to diagnose because if the brake pad drags as above and then the motor home is parked for a period of time (as short as 20 minutes), the piston may cool and decrease in diameter, releasing the piston from its binding condition.

What technicians will look for, what is covered

Diagnostic signs of the defect include:

• Piston dust seals/boots that are cracked or appear discolored (white powder markings).
• Front wheel seals that show signs of damage.
• Front spindle caps that show signs of heat damage or leaking.
• Heat damaged ABS sensors and wheel speed sensors; ABS sensors that have stopped functioning at various speeds and may have intermittent loss of function and associated fault codes.

Rotors with radial cracks are NOT considered recall related damage unless there is other evidence of damage. Such cracks are typical of “riding” the brakes downhill, absence of a tow car brake system and continued hard braking. If the cracks are severe enough to merit replacement that would be at the owner’s expense.

Rotor colors also vary from vehicle to vehicle, and some discoloration and transfer of brake pad material along with brake pad wear is normal. However, if the rotor exhibits significant transfer of brake pad material, that may be related to the Bosch defect. Similarly, if the brake pads show a rough and damaged surface associated with significant material transfer, that would be considered defect related damage. Replacement of both rotors and pads in this case would be covered by the interim repair procedure.

Affected owners will be contacted

Again, Workhorse will notify all affected owners with instructions when the recall remedy is available. In the meantime, affected owners of W20, W21 and W22 Workhorse chassis should simply be aware of the warning signs noted above and have their brakes inspected just as they normally would should any question arise about their functioning.

[oemtech]

Same song - verse #3

[Ron & Dee]

Quote:

If the motor home is not driven for extended periods of time (typically six months or longer), the phenolic material may absorb and retain moisture from the atmosphere, which may result in an increase in the piston diameter. Motor homes operated more frequently are not likely to experience any problem because the heat generated during braking under normal conditions inhibits the absorption and retention of moisture in the phenolic material.

My MH must be one of the odd balls then, because it NEVER sat for one month without being driven. In fact my MH is driven quite frequently,several times a month even though we don't full time, and still had brake failures

But I'm sure there must be other reasons why I had brake failures

Ron

[Spoonman]

Don`t need rhetoric, need calipers. Is anyone listening??????

[JCM]

I have had lockups after driving for hours or days (when heading south) in pouring rain.

[DriVer]

Quote:

Originally Posted by Spoonman Don`t need rhetoric, need calipers. Is anyone listening??????

I believe they are indeed listening. Early on when there was "No News" everyone was up in arms posting why don't they say "something" -- now that information is being presented more often, it's called rhetoric.

Perhaps Workhorse, Bosch and the NHTSA should keep us in the dark so we can just keep guessing what they are going to do next.

Honestly - I don't think anyone wants that. Movement toward the resolution of the campaign by the release of frequent information about the 90501-C is better than no information at all. It is also better that the information remain out in the open where all interested parties can have an idea of what to expect during this process.

As soon as Bosch can deliver the caliper kits that's when the campaign will start and there's nothing I believe that anyone can do until that first freight train full of kits pulls up to the warehouse and distribution center. Workhorse and its network of dealerships is ready to begin this process on receipt of the parts. My rally cheer is therefore, "Let's Go Bosch!!!"

[Ron & Dee]

Quote:

Originally Posted by JCM I have had lockups after driving for hours or days (when heading south) in pouring rain.

Maybe that's where you went wrong, should have been headed towards the desert

Ron

PS
Driver, keep up with the reports, I like being informed.

Thanks,

ron

[roadwalt]

What technicians will look for, what is covered

Diagnostic signs of the defect include:

• Piston dust seals/boots that are cracked or appear discolored (white powder markings).
• Front wheel seals that show signs of damage.
• Front spindle caps that show signs of heat damage or leaking.
• Heat damaged ABS sensors and wheel speed sensors; ABS sensors that have stopped functioning at various speeds and may have intermittent loss of function and associated fault codes.

What good is this?
I had three of the above problems, diagnosed by a WHRC and they still would not give me any assistance with the $1300 repair bill.

Maybe because I didn't let it get to the point that it burned up.
I'm the only thing burned up...
Me thinks they talk with forked tounge....

[DriVer]

Quote:

Originally Posted by roadwalt • Piston dust seals/boots that are cracked or appear discolored (white powder markings). Me thinks they talk with forked tounge....

roadwalt, Absent item #1 it makes it difficult to sustain the damage incurred in 2,3 & 4. When did you attempt to get your reimbursement? I'm also wondering if the SC properly documented your case?

[mfire1339]

roadwalt,

I would contact the Administrator, National Highway Traffic Safety Administration, at 1200 New Jersey Avenue, SE, Washington DC 20590, or toll-free Vehicle Safety Hotline at 1-888-327-4236. The more complaints the better. We need this situation fixed.

Mike

[DriVer]

Quote:

Originally Posted by mfire1339 I would contact the Administrator, National Highway Traffic Safety Administration, The more complaints the better. We need this situation fixed.

Mike, I have it from reputable sources that NHTSA signs off on communication between Workhorse and its customers because they are a party to the recall.

I believe that Workhorse is going with what was investigated by NHTSA and that's what's in the documentation that everyone has received.

I don't disagree that a complaint might be filled however I don't know how much if anything can be done now that NHTSA released the campaign. It isn't at all difficult to see where people have been getting reimbursements where evidence is present for issues that can be attributed to caliper failures.

NHTSA established the line of evidence in this case and absent that, what can compel anyone to pay damages that are not sustained by evidence?

[Dagwood]

Well I have finally joined the game. While replacing my tires I eyeballed my rotors and found the left front was cracked. After buying two rotors from Brazels I took my Dolphin down to Bill Cramer Chevrolet in Panama City to replace both front rotors and brake pads. While doing this they dicovered the right front caliper was stuck with pad transfer to the rotor. WH will replace that but for now the caliper is back ordered. Any suggestions?
All gramaticle errors are unintensionble
Bill Cramer is the new name for Tommy Thomas Chevrolet.

[max49]

Can someone explain this to me?

If you ride the brakes they get hot, they crack the rotors and burn up the pads and abs units and make brake dust.
If you have a faulty caliper, or 2 or 3 or 4, that does not release, it does the same thing, it rides the brakes for you.
So can someone tell me how in the world can someone prove that the owner 'rode the brakes' when there is a recall on the calipers because they stick ?

[DriVer]

Quote:

Originally Posted by Dagwood WH will replace that but for now the caliper is back ordered. Any suggestions?.

Call either one of our sponsors Brazels or Redlands and ask them if they have 1 caliper in stock that they can sell you, IF you're in a hurry to get back on the road.

There's a post here featuring $95.00 calipers however I don't know if those are still available. If you are not in a desperate situation, you may just have to wait for the caliper to come in.

This situation we are finding ourselves in obviously was inevitable. How can Bosch keep restocking old style calipers yet tool up for the new style caliper at the same time? (I thought that was a good question by the way )

We have been told that the legacy parts will be available throughout the "Interim" period however I am expecting a line in the sand at some point will be drawn. Is this the definition of Catch 22?

I do believe that there will be parts available it's just that they must be going through a bunch of these things plus there are other companies that are buying the same caliper either for stock, parts or production. It's a small world out there when only 1 supplier is making the caliper.