Parking Brake Chamber???

Thanks for all the replies and advice.

That is the way the AP works on mine also. It has its own pump that is separate from the power steering. I was in a construction zone prior to losing the service brakes and had to brake hard a couple of times so that I didn't run over a 4 wheeler that cut a little to close in front of me. I'm having the shop flush the brake system and put in new brake fluid. The fluid in it is probably the original fluid which would make it 20 years old. I figure it's time for a change anyway.

On my 2001 workhorse chassis the Auto Park is totally independent from the service brakes. The auto Park has its own pump to hold the park brake off. If your service brake pedal went to the floor and is working now there is a good chance that the brake fluid was hot and caused the pedal to go to the floor. I would recommend changing the brake fluid as if it is old it probably has moisture in it that will boil and cause the problem. Were you in mountains or using the brakes hard?

As I said I'm not an auto park expert.

But I know a bit about the service brakes.. On my W series they are HYDROBOOST

This means they use power steering pressure to boost the brake pressure....

I'm wondering where the Auto Park gets the pressure to release.. Can it be from the same source.. IF SO then if it is leaking the result would be a loss of Power Steering/Brake fluid and.. Well. this could cause problems.

HOWEVER I DO NOT THINK excessive brake pedal travel would be one.. When pressure is lost it is HARD braking (Hard to press) YOu can tell this because with the engine off if you press the brakes the electric pump that kicks in is not as fast as the engine powered pump so the pedal goes down... SLOWLY .

This is a 36 foot Damon Intruder 352 and is a single axle gas couch. I realize that the AP has nothing to do with the service brakes. It also has what on a car I would call an emergency brake pedal on the left side of the steering column. Not sure if that is what you would call it on a motor home. I'm not having them do anything to the AP system. The cost they quoted is way to expensive and I haven't been using the AP system anyway. It is disconnected.

dtucker3usa wrote:
That's exactly what I'm having them do. They tried to tell me that changing the brake fluid would cause other problems. I figured it couldn't be any worse than having no service brakes after driving for a hour and a half. Wish me luck.

I originally thought that you had a parking brake pedal going to the floor, along with the AP system and maybe you do. A manual parking brake pedal that is.
With 4 wheel service brakes pedal going to the floor, it could be just air in the lines or with boiling brake fluid. Usually the latter will recover in 8 hours or so, but should be replaced, as the boiling point is more around 212F, rather than 400F+.
The solenoid could be part of the AP system and do know that the V3 self contained system has one. Prices you quote seem out of sight and I would have run by now.
Again, keep in mind that the AP system has nothing to do with or is there any connection to the service wheel brakes. Manual, AP or both is a drum brake on the drive shaft and behind the transmission. As for emergency brakes, there is none on any vehicle I know of. They are parking brakes and maybe might stop you if not going more than a few mph.
I've never seen an old P30 gas coach more than 34ft that didn't have a tag axle, but it is what it is. At 34ft, they usually have a GVW of not more than 15K lbs, have a tranny parking pawl and don't require the AP system.

That's exactly what I'm having them do. They tried to tell me that changing the brake fluid would cause other problems. I figured it couldn't be any worse than having no service brakes after driving for a hour and a half. Wish me luck.

MountainAir05 wrote:

dtucker3usa wrote:
It is 36ft long, no tag axle. They said they checked the brake lines for leaks, didn't have to add any fluid to the master cylinder. If the brake fluid got hot to the point it was boiling would that cause the service brakes to fail?

Yes

I'm with dtucker. If the brake fluid got hot, you would lose service brakes. The brake fluid should be removed and replaced. If it was my rig, I'd move it to a different shop.

dtucker3usa wrote:
It is 36ft long, no tag axle. They said they checked the brake lines for leaks, didn't have to add any fluid to the master cylinder. If the brake fluid got hot to the point it was boiling would that cause the service brakes to fail?

Yes

RLS7201 wrote:
Every thing you ever wanted to know about Auto Park
Old Used Bear is the go to guy for Auto Park.

Richard

This is not really an auto park problem. The auto park has been disconnected for some time now and I've been using the foot pedal emergency brake. I've read a lot about the auto park system that Old Used Bear has posted. Very good info from him.