MCI 9 Air loss question?

[grantgoold]

I have the 1984 9 and I am losing air pretty quickly once shut down to 60 psi. It stays at 60 psi for days. I have checked the front wipers and am replacing both manifolds that were leaking. I also have a leak that you can hear coming from somewhere near the center of the drive axle. No chance to get underneath yet 

Any ideas? What gets charged after hitting 60 psi?  I the airbags hold air. I have been told that the bus appears to lean to the driver's side in the rear.

I cannot tell from my maintenance manual what might be the offending valve.


Thanks

Grant

[Buffalo SpaceShip]

Grant, most coaches have an accessory "circuit" on one side of a regulator and check valve for running everything besides brakes... suspension, fast idle, door(s), horn, wipers, etc. Since you hold 60psi for days, I would think your problem is on the accessory side. My old MC8 had a few regulators in the spare tire compt. for the door valve, etc.

Your levelers and bellows check valves are likely in good shape if the suspension stays up. So it could be an easy fix (knock on wood).

Sounds like it's soapy water time!

Good luck,
Brian B.

[Stan]

A small correction on Brian's suggestion about leveling valves. When sitting in the center position, the leveling valve should not leak any air out the exhaust line. If it is leaking, the air could be coming from the suspension or from the supply tank. Either one will cause the tank pressure to drop to the 60 PSI level. Follow all safety precautions before going under the bus and then stick the end of the leveling valve exaust hose into a cup of water and watch for bubbles.

[John E. Smith]

If this is a NJT bus (or other east coast bus) check for cracked or corroded hoses and/ or fittings on the tag air line that goes to the air bag.  Had that problem on our Tolar bus a while back.  It too leaned to one side a bit.

You say it sounds like air leaking near the center of the drive axle -- possibly.  But, as we have found out, any leak in either axle will sound like that.  The problem is that there is a big open area inboard of the wheel wells -- the sound from the leak will echo there and make it sound like it comes from the center.

Like Brian said, sounds like soapy water time!