Air leakage solved

[Bill B /bus]

started Monday AM with mechanic help to check for the source on an air leak near the drivers side suspension on a 102A3. I say suspension because the drivers side went down within an hour after parking. Jacked the bus up and on the blocking. Attached shop air and built pressure. Leak alright. Finally found that the relay valve was leaking out the release port on the bottom. Read the manual and found that it could be a leaking brake can diaphragm(s). Yep it was. Called US Coach for some guidance on the beat approach. I've seen those springs before when someone didn't cage the sucker. Bill Miller said" No worries just take can out and remove the clamping rings. And don't bend them."
Pulled the drive tires and forward shocks for access. Raised the air pressure again to make a final check that we had isolated the problem. Found the inversion valve leaking. Parts arrived the next morning. Cans are as Bill said "No worries." Just a pain to get the rings on and secured. Inversion valve was another story. I thought we were going to have to use the flame wrench.
By Tuesday supper time I had the cans installed, inversion valve replaced. I was out of gas by then.
Today saw a final air check and lo' and behold the original suspension leak made itself heard. Found and fixed that one. Then found what turned out to be the last one.
Brought the bus home before supper.

Moral of the story. Don't ignore the air leaks. I did have a suspension leak. I knew that. I didn't think that another leak had developed. The diaphragms were really bad. If we hadn't caught the problem I could see a service call on the side of the road. The mechanic help has a 96A3. He already had hew rear drums, shoes, rollers and springs. He's adding new diaphragms for the can rebuild after he saw mine come apart.

Leaving Friday for a loop from Maine to Cincinnati,Ohio;Goshen, IN; Saratoga Springs, NY via Soo Locks back into Maine in time for the color.

[Sam 4106]

Since your original air leak was in the suspension, what did you do to solve that leak? I have an air leak on both sides of the rear suspension and your solution may help me solve my leaks.
Thanks for any help, Sam MC8

[Bill B /bus]

You need several things:1) a quiet area,2) a compressor, 3) leak detection solution(soapy water) and 4) decent ears and eyes,  Bring the bus air system to operating pressure using the air compressor (2) in your quiet area (1). With (4) try to locate the leak with sound then use (3) with (4) for the visually accessible fittings. Sorry to be a smarta** but it was not to be resisted. Seriously don't forget the air bags.
For most leaks I try to zero in with sound and use my hand to baffle the sound. That will usually pinpoint the leak. If you can't decide which fitting is leaking then break out the solution. Sometimes you can't squirt the area with solution. then wet your finger and find the cool spot as the moisture is evaporated by the moving air.
Sometimes the biggest problem is keeping the air pressure up and getting the area quiet because of the compressor noise.

its a slow and painful process.

Good luck
Bill

[bevans6]

I have heard of ultrasonic leak detectors, has anyone tried those?  http://www.reliabilitydirectstore.com/Ultrasonic-Leak-Detectors-s/51.htm

Not inexpensive...

Brian

[BG6]

1)  Take the coach to a DIY car wash, and blast all the crud you can out of wheel wells, engine bay and underneath.  If you take less than two minutes per wheel well, you didn't get it all.

2)  Get a (NEW) garden sprayer, fill it with water and a long squirt of dish soap (maybe two), a pair of safety goggles and clothes which you don't mind getting wet and greasy.  Go under the coach (BLOCKED FRAME or a pit) and just spray anything that looks longer than it is wide -- pipes, wires, you name it -- and look for bubbles.  Get every joint and device, but don't ignore the middle of the line.

3)  Get a stethoscope and listen along every foot or so of the tunnel.

4)  Visually inspect as much of the air system as possible, looking for rubbing points, corrosion, damage or other likely failure spots.  Fix everything that needs or looks like it may someday need it.

5)  Sit back and smile when the coach next to yours develops a list to port 5 minutes after the engine shutdown.

[bobofthenorth]

I have heard of ultrasonic leak detectors, has anyone tried those?  http://www.reliabilitydirectstore.com/Ultrasonic-Leak-Detectors-s/51.htm

Wanna buy one?  I find mine completely useless for detecting air leaks.  Squirt bottle and soapy water is what works for me.

[Busted Knuckle]

Get a stethoscope and listen along every foot or so of the tunnel.

Hmmm I heard of a guy who tried that, and low and behold he heard air leaking @ 4 out of 5 holes he drilled to check for leaks.

Upon getting help fixing those leaks it was determined he hadn't had any leaks there until his drill bit hit the airlines!
FWIW
  BK 

[Fredward]

Hi Sam,
You have the added advantage of a pit in a nice clean quiet shop!
I've found all my air leaks with my ears and then the soapy water squirter.

One thing that you might discover on the MCI is there is a check valve in line with the leveling valves. The check valve (as I recall) is on the compressor side of the leveling valves. It keeps air from bleeding back from the air beams into the system if the system pressure is less than the beam pressure.

The curb side rear on my MC-5 would settle after a day or so parked. I was all concerned about leaking beams and bags and one of the guys at C&J bus said to replace that check valve first. It solved the problem.
Fred

[BG6]

Get a stethoscope and listen along every foot or so of the tunnel.

Hmmm I heard of a guy who tried that, and low and behold he heard air leaking @ 4 out of 5 holes he drilled to check for leaks.

Upon getting help fixing those leaks it was determined he hadn't had any leaks there until his drill bit hit the airlines!
FWIW
  BK 

Yeah, that would be a problem.

I listen to the tunnel itself.  It makes a really great sound amplifier.  A small leak in a coupler on an air line in the tunnel can be heard a couple of feet away.