View Full Version : Air Brake Problem?

05-19-2008, 08:02 AM
We are also new to RVing. We took our 08 Crescendo to a Boy Scout campout this past weekend. First trip with our new RV. We have been driving it quite a bit since we bought it three weeks ago. It had to go back to the dealer to make some small repairs, so my husband is getting pretty comfortable in the driver's seat.

On our way to the campout we stopped for fuel about halfway to our destination. After fueling we pulled away from the tanks and the air brake low pressure warning came on. As we pulled around the parking lot, we lost all pressure and power steering. My husband applied the parking brake and we were able to stop. Thankfully we were moving at less than 5 mph. As we idled the air pressure returned to normal. During the walkthrough at purchase our tech told us not to ride the brake because that would result in loss of pressure, so we thought that was the case here. After testing the brake system in the parking lot, all seemed fine and we proceeded to our campout.

On the drive home yesterday, we continued to have problems with the air pressure, but only when we were at a stop with foot on the brake pedal. At each stop light my husband applied the parking brake so he wouldn't have to keep his foot on the pedal. Backing into the driveway took much longer because he had to keep stopping to let the air pressure build.

Has anyone experienced this? Is it an issue with driving habits or is the system malfunctioning?

Arthur Hayes
05-19-2008, 08:49 AM
I have had similar problems in the past but never with a RV. All mine happened with trucks, but the systems are the same. It sounds like a air line has popped loose from it's connection. This is a simple fix if in fact if this is what has occurred. You can do a simple test by parking on a level spot, chock the wheels, build up the air pressure, shut off the engine and release the parking brake and have someone step on the brakes as you walk around to listen for the air escaping. Once again I repeat, chock the wheels.

06-03-2008, 12:03 AM
Hi Art; You might also check your drain valves. The air line has a couple of drain valves to drain moisture from your air system. If the dealer 'cracked' them to drain moisture without fully tightening them you will get a gradual bleed off of air.
Also, you have a dessicant dryer on the airline. While having your brakes checked (you should have a pro do this, nothing is more important than your brakes), check the dryer.
Finally, you have air bags. A leaky bag will drain your air system, which unfortunately, decreases your braking. Check these as well.

08-12-2008, 06:58 PM
Check for leaks, that is the first thing you should do. When I first bought my coach I had problems with the air bag leveling valve on a Freightliner chassis. It is located right behind the left front wheel attached to the rail. It has a little hose attached to it and it got stuck on the exhaust position and I couldn't get the air bags to even lift the coach. So I had it towed to a Freightliner shop where they changed it out under warranty.
Now your problem sounds more like an air leak on the brake lines or the resvoir valves with the landyards attached to it might be open and it is losing air. It is very important that you take care of the problem as soon as posible, because you sure don't want to lose the air and that will result on your spring brakes taking over and you will not be able to move the coach. :idea: