Workhorse Addresses Bosch Brake Defect Recall

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January 13, 2010 by   13 Comments

Workhorse logoEditor’s Note: This is the second in a series of  technical reports from Workhorse Custom Chassis Inc., Union City, Ind., with information that Workhorse considers most important in helping motorhome 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. For more information, a copy of a previous technical report or to speak with a Workhorse source in more detail about a topic, contact Mike Knaack at (574) 294-8844/

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 motorhome 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 motorhomes 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 motorhome 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.

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13 Responses to “Workhorse Addresses Bosch Brake Defect Recall”

  1. Roger Braaten on January 27th, 2010 1:43 am

    I need the information regarding the possible Workhorse brake recall. To date I have received nothing. I own a 2001 Itasca Suncruiser on a Workhorse. What needs to be done to get the recall information?

  2. Tom McNeely on March 12th, 2010 11:43 am

    Roger, Sorry to inform you but there is no offical recall at this time. According to a E-mail from WorkHorse Support that I received yesterday

    “Dear Customer

    Here is the the response to your question :
    Campaign 50901-C

    Our Response:
    Thank you very much for your question. The recall has not ‘officially’ been released. The letters that were sent were INTERIM letters notifying owners of the potential problem. We are required to have 50% of the parts on the shelf before we can issue the official recall. We are working on adding a page to our website with notices and information. Please continue to watch our website for the page to go live.

    Workhorse Support”
    To determine if your MH is in this recall you can go to “” and register in the “My Motorhome” area. Once you have registered the site will tell you what is open “EXCEPT FOR THE BRAKE CAMPAIGN 50901-C” but you can question Workhorse support through this sight and at least get some information.

  3. Tom Lynch on May 29th, 2010 12:24 pm

    I own a 2007 National Dolphin on a w22 workhorse chasis. I have not had any brake problems yet but I live in Arizona (hot &dry) but I am now in northern Montana for the “summer” however we have been here for 2 weeks and it has been cold and wet. What are my chances of having a problem?

  4. Richard Lewis on May 31st, 2010 1:44 pm

    I have a Workhorse Custom Chasis W 22 with a mfg date of January 2003. I received the Interim Notice telling me of the brake problem. Here it is over a year since the problem was identified and I was told the final remedy was determined back when Workhorse notified me in December 2009. Workhorse was suppose to be starting the production phase at that time. Why is it taking so long to produce the equipment to fix this obvious safety problem. Can you find out what Workhorse is doing about this situation?

  5. tomLynch on June 17th, 2010 9:33 pm

    I would appreciate any advice regarding my question on 5/29/2010
    Thanks Tom

    Tom’s questions was this: I own a 2007 National Dolphin on a w22 workhorse chasis. I have not had any brake problems yet but I live in Arizona (hot &dry) but I am now in northern Montana for the “summer” however we have been here for 2 weeks and it has been cold and wet. What are my chances of having a problem?

  6. James Keesling on August 15th, 2010 6:55 pm

    Thanks for all of the information on the “brake recall” as the information coming direct from Workhorse has been very lacking. I live in Northern California and have a 2005 Itasca on the Workhorse format and so far (crossing fingers) have not experienced any of the stated problems. Let’s all hope that the recall parts are quick in coming prior to any major problems/repairs.

  7. W.C. Smith on August 28th, 2010 7:42 am

    All- New Parts have shipped for the recall. There are two ways of getting the campaign done: At any Workhorse service center they should be able to order parts. However, there are “Select” program dealers (any dealer could opt-in, most did not) that were able to order parts by the pallet.

    Monument Chevrolet (Pasadena (Houston), TX) is one of those dealers (6 in the state, to the best of my knowledge). We are beginning to set appointments starting next week. We expect parts to arrive this Friday, and we will begin to make repairs the Tuesday after Labor Day.

    We will have more information on the web, including a self-assesment, by midweek, until the, contact me at or 713-580-1511

  8. W.C. Smith on August 28th, 2010 7:51 am

    Tom’s questions was this: I own a 2007 National Dolphin on a w22 workhorse chasis. I have not had any brake problems yet but I live in Arizona (hot &dry) but I am now in northern Montana for the “summer” however we have been here for 2 weeks and it has been cold and wet. What are my chances of having a problem?

    To TomLynch: The propensity for having a problem is most closely linked with how often you operate the coach, more than the environment. The issue, as I understand from Workhorse/Bosch engineering, is the the piston in the caliper is made of phenolic (a fiber-reinforced thermoset plastic, think high temperature fiberglass). As moisture builds in the brake lines (minimized by operating the coach and doing scheduled brake flushes), braking causes the fluid to boil (as little as 2% moisture in DOT 3 fluid lowers the boiling point by over 25% (100 degrees)) the additional heat this causes the phenolic to expand, applying the brakes. As the brakes come on uncommanded, the driver generally puts more and more throttle in it. More heat, more expansion, more fluid boil, etc. and the coach powers to a stop.

    Bottom line: If you are operating the coach and maintaining the coach regularly, you are less likely to have the issue, but no guarantees. My contact information is in the previous post, feel free to contact me.

  9. Jeff Hunt on September 23rd, 2010 11:25 pm

    Sept 18, 2010
    FYI, I recently recieved an authorization for recall service for my 2004 Winnebago 35U (Safety Recall 51101-C). This is the final remedy by replacing the four Bosch brake caliper assemblies.

  10. John Wagner on September 27th, 2010 11:35 am

    We own a 2003 30′ Allegro, Vin #W22-5B4MP676033363295. While driving on the Interstate, brakes got hot and failed, exactly as you describe above. On 09/15/09, I repaired the MH at a cost of $435.34, no labor. We feel we should be reimbursed for the amount of the parts, which is $435.34. Please advise, as to how we go about getting this done. We have the actual bill and can send it to you, but need an address to do so. Please advise. Thank you.

  11. Frank Smith on October 9th, 2010 7:38 pm

    Where is a Workhorse Dealer near Anthem Az. 85086

    623 551 3376

  12. Ken Baur on October 11th, 2010 4:10 pm

    I have a 2004 Fleetwood Southwind on a Workhorse chasis. I experienced the same type of brake failure that you described. After the repairs were made I received a notice of recall from Workhorse. The problem is that I live in the St. Louis, Mo area and the only dealership that was an authorized repair shop (Degal Truck Repair) does not do warranty work for Workhorse anymore. Is there a repair shop in the greater St. Louis area that can do the recall work?

  13. Tom Gascoigne on February 19th, 2012 1:59 pm

    I have a 1997 Pace Arrow on a Chev P 30 chassis. I have had three brake failures due to overheating of brakes. This chassis has the Bosh calipers. I thought the calipers were sticking but now after reading above info it seems the caliper pistons are at fault. What is the solution? I live in the Northwest where there is lots of moisture. Would changing brake fluid out to syntetic help. For the latest problem I replaced caliper. Should it have come with up-graded pistons? I fear driving motorhome that I will again have problems. So far have been lucky and loss of brakes did not cause any personal harm.
    Look forward to response.
    Tom Gascoigne