Someone just had this problem, but I can't find the thread. Today braking suddenly air pressure started dropping fast. Parking brake no issue. Get off the brakes and it builds back up. Does this require a Meritor specialist or just someone air brake knowledgeable?
I limped into a KOA after driving through Atlanta. Whew!
In my case is was a brake pod.
-
Engine at idle and air pressure builds up. -
Put foot on brake and air pressure drops fast.
The Coach-Net mechanic that fixed mine said you can reverse a bad pod's function so you have service brakes but no parking brake.
If a bad pod is your problem and road mechanic will be very familiar with this. The only problem my mechanic is the pod on my 1999 40ft U320 are 30-24's, which he hadn't seen in 10 years. He thot current standard was 30-30's. So he had to make a parts run two times.
best, paul
Looks like Paul beat me to it as I was typing. Here's his thread on the subject
Lost Air in BOTH Tanks in Salem, OR (http://www.foreforums.com/index.php?topic=13354.0)
-M
Sounds like a pancake in the service brake pod, not the parking brake. The pods are double, one part for service brake and other part is for parking brake. Would think any truck mechanic could solve that one real easy, most truck stops should stock those pancakes.
Dave
Woohoo! Chafed brake line! The guy from the truck stop ERS is on his way to put something together. I told him he would earn himself a forty buck cash tip...
I was having them come over to isolate that brake because they didn't have a 30-24 and I would have had to wait until Monday.
Now he's excited too.
Seems cash does talk.
Hi Dave,
Maybe a leak in a brake air line? (Don't ask me how I know.) Do you or your spouse hear air leaking when the brake pedal is held down?
Jim
... Today braking suddenly air pressure started dropping fast. Parking brake no issue. Get off the brakes and it builds back up. Does this require a Meritor specialist or just someone air brake knowledgeable?
Dave Head & Starr Martin
It was a chafed line. I thought it was a bad diaphragm in the service canister since it had just happened to someone else.
Hi Dave, What is a "chafed air line"?
A brake line has rubbed through. Could be on another line or any chassis component. Easy to find, as there will be a massive air leak.
If the chafed air line is on the brake system, it will only leak when the service brakes are applied. If a suspension air line, it will leak all the time.
Brett
Raising the coach and blocking it, then crawling around under it with a light, you can find all sorts of interesting little things that might need attention, like a Ty-Rap to hold wires or hoses back from something, might see rusty area that needs some attention, there are many areas that need a little attention once in a while. Enjoy, I find it an adventure ;)
One that rubs on something and chafes until it wears through. Sorry if I miss-typed