Dangerous Parking Brake Design Defect

[ugly dog]

Anyone who has one of the Workhorse chassis motor homes with auto park, watch out! Almost anything can cause the parking brake to apply at any speed and without warning, also both park and the parking brake can suddenly release while parked with the coach running. We have experienced both with ours and it only has 6000 miles on it. I heard a relay click and both park and the parking brake released while I was checking our motor home out for our next trip and it rolled 20 feet before I could get the main brake on and park wouldn't re-engage till it was shifted out of park and back into it. The other day while traveling 45 mph, the parking brake locked up so violently that it caused the coach to stall and stop with the brakes locked in the middle of the highway. I wasn't able to restart it or release the brake to move it from the center lane until I disconnected the battery and reconnected it. I did some reasearch and found that the sudden self application of the parking brake is a rather common problem that may be caused by any drop in voltage below a certain level, for example, starting your generator, running out of gas, electrical disruption of the ignition, defective alternator, blown fuses and minor short circuts.
I've been a bus mechanic for over 20 years, a fleet owner and driver with millions of miles of experience and until now I have never been afraid of a vehicle.
Does anyone know of any safety device that can be installed on this brake system to prevent lockup while driving? I didn't think a brake system that can lock up on it's own was legal.

[ugly dog]

Anyone who has one of the Workhorse chassis motor homes with auto park, watch out! Almost anything can cause the parking brake to apply at any speed and without warning, also both park and the parking brake can suddenly release while parked with the coach running. We have experienced both with ours and it only has 6000 miles on it. I heard a relay click and both park and the parking brake released while I was checking our motor home out for our next trip and it rolled 20 feet before I could get the main brake on and park wouldn't re-engage till it was shifted out of park and back into it. The other day while traveling 45 mph, the parking brake locked up so violently that it caused the coach to stall and stop with the brakes locked in the middle of the highway. I wasn't able to restart it or release the brake to move it from the center lane until I disconnected the battery and reconnected it. I did some reasearch and found that the sudden self application of the parking brake is a rather common problem that may be caused by any drop in voltage below a certain level, for example, starting your generator, running out of gas, electrical disruption of the ignition, defective alternator, blown fuses and minor short circuts.
I've been a bus mechanic for over 20 years, a fleet owner and driver with millions of miles of experience and until now I have never been afraid of a vehicle.
Does anyone know of any safety device that can be installed on this brake system to prevent lockup while driving? I didn't think a brake system that can lock up on it's own was legal.

[edgray]

UGLYDOG: First let me say WELCOME TO iRV2.COM You've come to the right place for fellowship and answers to all things RV. Are you that "bounty hunter" guy on TV??

Second, let me say how sorry I am to read of your parking brake problems. It will certainly get a LOT of attention from our members. If you will please add some rig specific information to your signature, we will better be able to help. For example, please specify WHICH chassis you are talking about. I'm already confused ( not unusual), because I thought that the chassis which are equipped with the auto parking brake are so equipped because they do NOT have a park pawl in the tranny. You seem to be saying you have had BOTH features fail. Please help us help you with more specific info, thanks. And again, WELCOME! ED

[fiero34]

it seems all of the auto apply brake systems are causing problems mine is on a p30 chassis last year chevy made it before selling to work horse, but the problem is almost always one or both of the pressure switches leaking out and then on comes the brakes as your tooling down the interstate after your reservoir is pumped dry look
under auto apply and you will find a lot written on it

[max49]

OMG I have to get another new MH and It will probably only have 310 HP and a high dog house.
Thanks alot ugly dog, now I've got to trade this for sure and it's only 2 months old. Workhorse should buy it to show the assembly line what happens with sloppy workmanship.I don't trust anything electrical on my coach. And the thought of 1 or both of the things that happened to you is pretty scary. You're lucky someone didnt get killed in either case.
Edray, It has a "Park "position but it just puts the "Auto Apply" on they both do the same thing. I have no idea why they built it that way.
Since this forum is sponsored by Workhorse , it's too bad they don't come on and explain what to do about these problems. The closest WH SVC center to the Denver area makes it pretty obvious that MH's are just a big pain for them. "No appointments" for MHs , only acceptance date. Currently in Sept.

[Myron]

Yeah, don't make the mistake of shutting the engine off while driving. I don't care how much noise or racket it is making. The parking brake will come on and can leave you in the middle of the highway instead of along the edge.
I just wish my p30 had better brakes to start with. It takes just about both feet to get it to stop. Forget an emergency stop. Something really poorly designed here. The master cylinder was replaced. No help. Its a 2005 model if anyone is interested. 8.1 workhorse.

[max49]

Ugly Dog, what happened when your brake suddenly applied. That seems like it could be disastrous.
I tried it on mine at about 1 or 2 mph and it applies instantly. It's obviously connected to the drive shaft so even if it does'nt throw everyone thru the windshield it seems like it would rip the u joints out of the drive shaft. It's even dangerous to drive behind one
I wonder if the engineer who designed this drives one with his family with him.

[ugly dog]

Just to answer a few of the questions asked.
The chassis I have is a P32032 mfg either in 1999 or 2000 since the completed vehicle is a 2000.
As far as what happened when the brakes applied. I haven't checked the driveline yet, but there is a slight vibration now. I was leaning forward pushing the start button for the generator, I had my seat belt on and still hit the steering wheel with enough force to put a bruise across my chest and break a tooth, thank God I hadn't picked up anyone yet.
As far as when it rolled, the coach was in park, running, I heard a relay click, then I heard the brake release and it was rolling free, I know the shift lever was fully in park since I had shut it off and used the key to open some of the compartments before restating it to service the a/c. I haven't as of yet checked to see what transmission is actually on this unit, I need to get some heavier blocks to put under the wheels before I get under it to see what unit is actually there and how it works.
By the way, this thing is the worst stopping vehicle I have ever driven. The scariest part is I think this chassis is used on School Buses too.

[Tom N]

On my '05 W24 the transmission has to be in PARK for the automatic parking brake to activate.

[Alan554]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ugly dog:
Anyone who has one of the Workhorse chassis motor homes with auto park, watch out! </div></BLOCKQUOTE>

The auto park system used on Workhorse P-chassis motorhome chassis is a carryover design from the GM design that Workhorse purchased in late 1998. The system has been in use since the 80's at least and consists of a drum brake attached to the tail housing of the transmission. The brake is designed be "always on" for safety purposes by spring pressure. The brake is disengaged by hydraulic pressure when the gear shift (plus emergency brake released, if engaged) is moved from the Park position, releasing the drive shaft.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Almost anything can cause the parking brake to apply at any speed and without warning, also both park and the parking brake can suddenly release while parked with the coach running. </div></BLOCKQUOTE>

I'm not sure what you mean by "almost anything" can cause the failure modes you have experienced. There are solenoids, wiring, connectors, an electric motor, switches, etc. in the system. There is a service manual with troubletrees to diagnose the problem. Somebody has to find the problem and fix it.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I heard a relay click and both park and the parking brake released while I was checking our motor home out for our next trip and it rolled 20 feet before I could get the main brake on and park wouldn't re-engage till it was shifted out of park and back into it. </div></BLOCKQUOTE>

IMO, it is never a good idea to leave a 7+ ton vehicle running without block the wheels, but your post clearly indicates a solenoid or relay problem.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The other day while traveling 45 mph, the parking brake locked up so violently that it caused the coach to stall and stop with the brakes locked in the middle of the highway. </div></BLOCKQUOTE>

The auto park only acts on the driveshaft, thereby braking the rear wheels only. It is a drum brake with limited braking capacity compared to the service brakes.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I didn't think a brake system that can lock up on it's own was legal. </div></BLOCKQUOTE>

I think you are confusing a defective product with a product that needs to be repaired. If the auto park system "locked up on its own" when properly assembled, then it wouldn't be legal, but that isn't the case. My 1994 Bounder had the same auto park system your coach has and it never experienced either failure mode you describe in the eleven years and 61,000 miles I owned it.

[max49]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">My 1994 Bounder had the same auto park system your coach has and it never experienced either failure mode you describe in the eleven years and 61,000 miles I owned it. </div></BLOCKQUOTE>

Allen King, thaks for giving me some hope that I will not have trouble with mine either. Either way, I still think it's a dangerous design and just one more thing that could leave us stranded on the road. I would'nt have bought this one if I would have thought about how it must work and I doubt if I'll keep this one too long.
Mines back in the shop, for the 4th time and only 2 months and 4000 miles old. At least 10% are miles to and from the shop. The WH problems are by far the most and the worst.
I saw the new Ford Chassis on another Damon just like mine. I has way more ground clearance and the doghouse is barely any higher than the WH and flat usable space like the WH. Saleman said it had the same HP as the WH.

[Alan554]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">(originally posted by max49)I still think it's a dangerous design and just one more thing that could leave us stranded on the road. </div></BLOCKQUOTE>

I doubt that a truly dangerous design could survive over thirty years of production without attracting undue attention from NHTSA. There has only been one recall issued on the system (to my knowledge) and that only applied to one model year (1990), when Chevrolet apparently made some ill-advised changes.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I saw the new Ford Chassis on another Damon just like mine. I has way more ground clearance and the doghouse is barely any higher than the WH and flat usable space like the WH. Saleman said it had the same HP as the WH. </div></BLOCKQUOTE>

Actually, Ford is advertising higher HP & torque peaks with their new three valve version of the 6.8L engine, but until I see the proof, I will continue to say the 8.1L GM engine has more torque available across the rpm range. Its hard to argue with 400+ ft-lbs from 1000-4800 rpm.

[The Godfather]

On return from our 2nd weekend shake down on our new unit we stopped for lunch on the way home. Everything appeared normal on shut down. We disconnected the toad, had lunch and on start up of the unit I had a blinking warning light with a blinking autopark light. The transmission would not engage. Checked the main 60amp cb in the engine compartment after calling WH. Since it was OK, they advised me to have the unit towed to the dealer. Turns out that Winnie had routed the circuitry through a 15amp fuse (turn signals) and if it blows it also shuts down the autopark system. WH/WB paid for the tow and isolated the autopark circuit. I personally don't like the system and would prefer the old fashioned emergency brake system. P.S. the '05 Suncruiser W24 came with bigger brakes.

[DickNJo]

RTFM, Read the fancy manual. At least mine describes the AutoPark system, operation,Low Oil warning, escape method, and service requirements in sufficient detail.
Nonetheless I had a major headache with mine. Starting up after dumping at a hiway rest stop the monster would not release. Tried everything the book suggested to no avail. Phoned WH road service. Pleasant young lady suggested a blown fuse was a usual problem.Nope. She told me to call service shop, 60 miles away.
While I had the dash up,looking for the fuse I noticed the maze of wires and connectors attaching the steering column to the rest of the world. Looked promising,so I pawed around in it and,LO,the Park lights went out. Never called the shop but went on my way, now certain that some where in that mess was a loose connection.
Took me six months and a dozen recuranses to find it. We had just had a set of jacks installed. One of the leads was taken off the back of the pull switch. It had been made with a crimped butt connector, and one end was single crimped on the insulation, instead of the conductor.Don't know why it never failed while underway, that would have put me in the shop in a hurry. Maybe higher running voltage , maybe engine vibration, maybe the Lord looks after fools, I dunno. I made a proper crimp, and it hasn't failed in the last 3 years.
Don't blame the Engineers too much. Everything they do is filtered thru Customer relations, the lawyers, and then thru production cost control, who want to buy everything from the lowest bidder.

Dick and his DW, Jo, and Cisco and Pancho, the hysterical Mini Poodles
2000 Itasca Sunrise, 32ft
Workhorse, 18,000# P32 I guess
Home is where we Park it.