Park Brake Problems ?

[John 'Bo' Achord]

 I have a 42' 2008 Beaver Contessa with 20,000 miles. I purchased it used in 2011 with 11,000 miles. I went to move it out of the RV Shed and it acted like the Park Brake was still on. The RV has been sitting for about 3 weeks hooked up to 50 amp. service. I unhooked RV from the power service and rolled up the electrical cable. I have all four slides pulled in including the generator slide, The door and all storage doors are closed. I cranked the RV and let the air pressure build to 115 PSI. I hit the travel button to raise the RV 3/4" to 1"(Confirmed) to get it ready to travel. All of my gauges look normal. Oil Press. 50 PSI / Temp. normal / Trans. normal. This is the first time this has happen. The funny thing is that I just had my Transmission service by a authorized Aillison Trans. Shop. Everthing worked fine 3 weeks ago when I drove it home. So I am not sure if  there is a interlock keeping the RV from going forward or revesre or if I have a mechanical problem with the Transmission or the Park Brake or something else ? I can tell you that when I place it in D or R you can fill the Trans. kick into gear.  Any input would be greatly appreciated.  

[Gary Nash]

Sounds like your brakes are stuck to your brake drum.
Just my two cents worth.

[John 'Bo' Achord]

It is acting exactly like they are stuck. I heard of brakes icing up in the winter after the RV would sit up for a while , but was unsure about the humidity making them sick in the hot Louisiana summer.  Thanks for the input.

[Dwight Wilson]

I had the same problem after parking for a week in torrential rain in Oregon a couple of years ago. The brakes get stuck from rust. In my case I was able brake them loose by applying some throttle while in Drive. Don't over do it and maybe try a bit of Drive / Neutral/ Reverse, and they may brake loose.

[Frank Bannert]

Usually when the park brake is on the rear shoes are the ones that are stuck. I had this happen to me in Arizona on a freezing day and my coach wouldn't move. What I did was put it in reverse and they broke loose. This not the right thing to do but I had no choice if we were to leave and it worked. But this is also a way to break a air line so be careful how much you accelerate. On most coaches you have 2 sets of brakes 1 in front for stopping and the other is for parking.

[Sean Donohue]

I hve had this before too. All I did was gently shift between Drive - Reverse a few times and it finally let loose.

[Bill Sprague]

Parking breaks are applied with a large spring when there is an absence of air.  That absence is created by the parking brake valve or a failure.  The failure can be a broken airline or the compressor itself.  In other words, the parking brake and "emergency brake" are one in the same.  

So, if a little gentle rocking does not release the stuck brake shoes, there may be a failure (or leak) in the system that allows air pressure to release the mechanical parking brake.  

An excerpt from the California DMV driver training book:  "Spring Brakes ----All trucks, truck tractors, and buses using air pressure to apply the service brakes must be equipped with emergency brakes and parking brakes. The parking brake must be held on by mechanical force (because air pressure can eventually leak away). Spring brakes are usually used to meet the emergency and parking brake requirements. When driving, powerful springs are held back by air pressure. If the air pressure is removed, the springs put on the brakes. A parking brake control in the cab allows the driver to let the air out of the spring brakes. This lets the springs put on the brakes. A leak in the air brake system will generally cause the springs to put on the brakes."

The rest of it is here:  http://www.dmv.ca.gov/pubs/cdl_htm/sec5.htm

[John 'Bo' Achord]

Thanks for all of the great advice. I did find out that the cam was working properly by chocking the wheels and watching the cam bar roll , but the brake shoes on the drive axle were staying glued to the rotor. It had a build up of rust on all the brake shoes and rotors. As for as air leaks , the compressor was not cycling. Any way , after I saw and felt the brake shoes were glued to the rotors I gently went forward & backwards a few times and finally they broke loose. Everything is back to normal.  I only have 20,000 miles on the coach. Is this something that happens often ? If it does is their anything I can do to prevent this problem. Again Thanks for all the input. A Class "A" Coach owner for two years.

[Gary Nash]

It only happens when driving in the rain & you set your brake before they get dry. Try to use your brake enough to dry the pad & rotor.  Glad you got your coach rolling....