| Author |
Message |
Carl Olson (Carls_mci_9)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 22, 2005 - 7:36 pm: | |
My MCI 9 looses air when parked. It goes down 50 lbs in 60 min. The suspesion stays up at that presure,would it be a brake system leak. |
JR
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 22, 2005 - 8:24 pm: | |
It's probably 50 things leaking...brakes included. For starters: door control valves, fan and AC belt tension cylinders, the control valves and regulators for same, air tank valves, treadle valves, air suspension. leveling valves, kneeling valve if ex-NJT, wiper controls, wiper motors (park). Any valve, or hose connection is also a potential leak. Get some soapy water and start spraying. Diagnosis will be facilitated by connecting shop air to the coach using a dryer between the two. An air chuck fitting can be installed into the air system at the RH rear service door. Just set the air with a regulator for about 100 lbs (don't go over 120 lbs) and then you will hear some of the leaks, but most will be too small. Cumulatively the air gets out fast. Unless your air bags have been replaced, a lot of air could get out those. If you have an 83 or earlier model, you may have air beam leaks. The 87s don't have air beam suspension. Leaking air beams are best resolved by the use of adaptors that seal off the air beams. Air then goes directly to the air bags. Check under the driver area for leaks. What you'll likely see is "fizzies" on all valves. There are air pressure regulators everywhere and they will seep from age and sitting. Most of the parts to repair are cheap...AC and belt cylinders, and door control valves are expensive (relatively). The bus air leaking is not a serious problem as long as it isn't the brake system. The air suspension will be a nuisance as it settles on uneven ground. A working air suspension system will make a useable leveling device. Just get started. Tedious project. |
Gus Causbie (Gusc)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 22, 2005 - 10:04 pm: | |
I sure wish my 4104 would hold air that long!! |
H3-40
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 22, 2005 - 10:09 pm: | |
While working on our bus this afternoon, I noticed it was still holding air but only about 65lbs. It's been sitting since last Monday without starting so I guess that isn't too bad!
Ace |
Norm Edlebeck (Bandleader)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 23, 2005 - 2:22 am: | |
Carl,
I had same problem with my MC7 when it was parked. Found out it was the "pancake" in the emergency brake. Try it without putting the emergency brake on when shut off - put it in gear so it doesn't get away on you. Like Gus said, even after fixing that, I wish mine held 50 lbs for 60 minutes.
Norm Edlebeck |
Cliff (Floridacracker)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 23, 2005 - 9:11 am: | |
Carl,
JR couldn't have said it better.
I have found as you fix the air leaks, ones that were once quiet will show up as you increase the general pressure around the system.
The ones that hiss are fairly easy to find, its the ones that leak through diaphragm's that are a little harder to track.
Cliff |
Buswarrior (Buswarrior)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 23, 2005 - 11:32 am: | |
Hello incrimentalists.
Take heart, you don't have to find absolutely every last source of leak. Even a brand new coach will lose air over days.
If you chase after the loudest ones, you may be pleasantly surprised at the difference just one or two stopped hisses make.
I will clarify by suggesting you want to be fairly religious with the brake circuits to be leak free, a little seepage in all the other stuff is liveable.
The brake valving is relatively few parts compared to the rest of the air system.
One goal is infrequent compressor cut-in while underway. The more it runs, the sooner it will wear out$$$$.
Another is the ability to shut down for the 10 or 15 minutes at the campground gate to register, and be able to stay aired up so you may get straight in.
happy coaching!
buswarrior |
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