Help park brake stuck 80 miles from home

[Ron03Allegro]

I have a 2002 P32 Workhorse chassis with a 2003 Tiffin Allegro Class A.
It has just 25,000 miles on it. I am am the third owner.

The MH truck battery had a bad connection and this morning it put the Tiffin into an emergency parking brake mode. I was driving just 15 miles per hour and it stops dead like someone turned it off. I have no clue, I start it easily but then I see a AUTO PARK light on the dash. I drive it a block and it does the same thing this time I am stuck in park with no juice to crank. A good guy comes along by we jump start it and he follows me home, I replace a bad battery connection bolt and it's off again on our trip. The autopark light is on and will not go off and I hear a on and off electric motor like for the parking switch, I see no sign of brakes dragging so I do what I shouldn't have I drive 80 miles that way, until I stop for 20 minutes in a parking lot in priceville alabama. Try to start the RV it starts great, put it in gear that works but the electric parking brake is on and I can't move the RV. No sound of electric parking brake trying to work. What is the problem, a blown fuse, a blown electric motor. ???? Help!

[Unplanned Tourist]

Google '' Rotten Green Switch P32''
https://www.rvforum.net/threads/issu...k-brake.85987/

[garyspang]

I had it fail while driving on a highway. Left smoke behind me. Stopped on the side and undid the park brake linkage underneath on the driver's side. Had to jump the pump motor wiring to get the linkage to relax, so a linkage pin could be removed. Drove to a campground. Blocked off the wheels. Disassembled the small hydraulic cylinder and replaced the leaking internal piston O ring. Did this over 10 years ago, so more details are lacking. It could be in one of my old posts.

[Ron03Allegro]

Originally Posted by Unplanned Tourist

Google '' Rotten Green Switch P32''
https://www.rvforum.net/threads/issu...k-brake.85987/

Mine is Auto Park light always on, after initial battery connection failure.
I fixed the stripped battery bolt issue and it started fine. But it then was always showing the autopark light with and sound of some electric motor cycling from the dash area.
I was bad I drove it for 70 miles doing that electric motor sound, I did check several times if brakes where dragging and they were not at all.

At one point I stopped after driving for maybe 30 minutes for about 5 minutes, I continued same sound, same autopark light on, and no dragging parking brakes.

After 1.5 hours I stopped for 30 minutes and it started again no problem. still autopark light on but no electric motor sound from dash, it move to D drive or R reverse it wants to move but you can tell it is autobrake locked on not moving an inch.. I am told I may need to go back where the autopark cables head for the parking brake box on the drive shaft and remove a pin to loosen and disable parking brake.

I figure the problem is about the autopark switch mechanism and likelly that electric motor in the mix. I am physically and mentally beat, Too bad 2002 tifins or have no mechanocal support experts to remember what is what I thnk.

[Ron03Allegro]

Originally Posted by garyspang

I had it fail while driving on a highway. Left smoke behind me. Stopped on the side and undid the park brake linkage underneath on the driver's side. Had to jump the pump motor wiring to get the linkage to relax, so a linkage pin could be removed. Drove to a campground. Blocked off the wheels. Disassembled the small hydraulic cylinder and replaced the leaking internal piston O ring. Did this over 10 years ago, so more details are lacking. It could be in one of my old posts.

What year workhorse? Did have like mine just a yellow parking switch no mechanical parking brake?
Where was the linkage pin, I talked in another guy he said it should be in the back on drivers side rail not up front, but cable do run from front. Mine never dragged brakes until I stopped the second time and then they are on hard. Key thing autopark light will not go off.

[David 70]

If you heard the pump turning on and off, you had a hydraulic leak in the system. It most likely is what they call the rotten green switch, although it could be brown in color. This would be on the J71 system. Somewhere along the line they introduced a J72 system. Is your pump under the coach on the rh frame rail or is it up front? Does it have a cable or a hose going to the brake on the back of the transmission? If it has a cable, there will be a pin where it fastens to the brake mechanism. I have removed that pin with it under tension, but you have to be extremely careful in doing so. It took a pretty good pry bar to get it out. You will have no park after you do that. There is no park pawl in the transmission. If the pump kept running it is possible you burnt up the pump motor. Good luck.

[George Schweikle]

The autopark defaults to brake ON, and the motor runs a pump to release the brake. Short term the only way to move is to unhook the cable from the autopark to the parking brake drum on the driveshaft.

I have some material from the past autopark expert who is no longer operating. PM your email and I will send it.

Originally Posted by Ron03Allegro

What year workhorse? Did have like mine just a yellow parking switch no mechanical parking brake?
Where was the linkage pin, I talked in another guy he said it should be in the back on drivers side rail not up front, but cable do run from front. Mine never dragged brakes until I stopped the second time and then they are on hard. Key thing autopark light will not go off.

[Isaac-1]

This may have started as a rotten green switch problem, but after driving for 70-80 miles with the warning light on and the pump cycling, you may now be dealing with a burned out pump.

[garyspang]

2003 P32, also had a yellow park pull switch.
When the hydraulics are off, the heavy-duty spring on the cylinder assembly applies breaking force to the drum brake behind the transmission. It was necessary to run the hydraulics to overcome the spring force and thus relax the linkage, so the linkage after the cable near the drum brake could be disconnected. CAUTION: NOTHING WILL PREVENT THE RV FROM ROLLING WHEN THE NORMAL BRAKE IS DISENGAGED OR THE FOOT IS REMOVED FROM THE BRAKE PEDAL.

At another time, the pressure switch near the cylinder failed.
I thoroughly studied the entire system on published documents until I could trouble shoot it with confidence. It was the most frustrating feature of the P32 chassis.
I sold it working great with 180,000 miles, always using a by-pass oil filter and a pre-oiler. My wife wanted more space, so we went from 28 to 35 feet.

My present 2004 W22 chassis has a mechanical foot activated park brake and a built-in transmission Park lock. What a relief.

[Ron03Allegro]

Originally Posted by David 70

If you heard the pump turning on and off, you had a hydraulic leak in the system. It most likely is what they call the rotten green switch, although it could be brown in color. This would be on the J71 system. Somewhere along the line they introduced a J72 system. Is your pump under the coach on the rh frame rail or is it up front? Does it have a cable or a hose going to the brake on the back of the transmission? If it has a cable, there will be a pin where it fastens to the brake mechanism. I have removed that pin with it under tension, but you have to be extremely careful in doing so. It took a pretty good pry bar to get it out. You will have no park after you do that. There is no park pawl in the transmission. If the pump kept running it is possible you burnt up the pump motor. Good luck.

I pulled the pin and that released the autopark brake, so we are parking on flat places and chalking the wheels. It is a J71 Autopark on a 2002 workhorse and yes the j71 pump has been cycling and now I see brake fluid sweepage from the front drivers side area where the autopark pump I cant easily see lives which must be very near the brake reservoir and the master cylinder. I saw the green switch apparently replaced by general grey and I doubt that is what has caused my j71 troubles. So does J71 autopark use the common brake fluid reservoir? How can I stop the j71 pump from cycling?. Wish I knew what fuse in my 2003 allegro I could pull to disable J71 or what relay. Tomorrow morning I will put on leveling jacks and crawl under to inspect and hopefully disable j71 pump motor. I am checking out of fort wilderness disneyworld by 11pm tomorrow. Rather worried about leaking brake fluid which I am sure is from the j71 system but may also drain the brakes.

[SafariBen]

Are you sure it's brake fluid leaking? I would think it would be ATF or power steering fluid from a separate reservoir on the pump in this case, or the power steering system on other models.

[Unplanned Tourist]

Originally Posted by SafariBen

Are you sure it's brake fluid leaking? I would think it would be ATF or power steering fluid from a separate reservoir on the pump in this case, or the power steering system on other models.

Agreed. The park brake system used PS pump and oil. Not brake fluid.

If you're not sure how to tell the difference, poke a finger in the brake resevoir and give it a sniff, then pull the PS tank dipstick and smell it. Very different smells.

[SafariBen]

Brake fluid dissolves in water amazingly well. ATF will make a rainbow sheen, or make water bead up on your finger.

[Isaac-1]

Putting Brake Fluid in the Automatic parking brake system is a recipe to need about $2,000 worth of new parts as it will eat through the seals in the APB pump and actuator. The correct fluid for the APB system is Dextron ATF fluid.