Community Forums

Just For Fun · 03-20-2023, 06:44 PM

Here's an interesting one for you.

Just tried to pull out of my park space and within about one mile, 90% of my air bag pressure was drained!!! This caused the Parking Brake (PB) light to start beeping.

But when I put the PB back on/engaged, the air pressure begins to build normally to full (3/4). If I push the PB off/disengage, and begin to drive, the bag air pressure starts to drop.

If I'm running down the road at least 20 MPH and or standing still in Neutral racing the engine, the air pressure begins building again.

Thoughts????

Solutions?????

Thanks.

rgvtexan · 03-20-2023, 06:57 PM

Air Leak in brake line or can.

twinboat · 03-20-2023, 07:44 PM

The guages on the dash are air tank pressure gauges for the primarlly air brakes and not the air bags.

When you push in the parking brake button, air is sent to the rear air brake chambers to release the parking brake.

There lies your problem. A brake chamber has failed or a air line going to them has ruptured.

As the air leaks out, the parking brake comes on as a safety feature.

May want to call a road service guy who fixs air brakes otherwise you will need it towed to a shop.

code2e · 03-20-2023, 07:50 PM

Each of the rear air brake chambers on your coach have 2 rubber diaphragms and a spring inside. One diaphragm activates the service brakes when you press on the treadle. The spring applies the same force to the same slack adjuster as the service brake when parking is applied (knob pulled). The other diaphragm, likely your problem, is pressurized when knob is pressed in. That diaphragm retracts and holds the spring back from the service brake. Likely, you have a pinhole in that diaphragm and air pressure leaks off when park is released.

If you securely chock all wheels to be sure coach can't roll, press in park brake knob and you should be able to hear air escaping from one of the rear brake chambers. It is good practice to replace both chambers when one fails. It is very dangerous to attempt to replace a park diaphragm in a used chamber. Fortunately, replacement chambers are not expensive. Would be a good time to replace the service diaphragms as they are cheap and will be off while the chamber is off.