| Author | Message | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 21 Registered: 10-2007 Posted From: 207.161.152.27 Rating: N/A |
I'm looking for a part # for my 84 MCI 9. Even if I had the proper name for the part would be great. The part is a air valve that is located on top of the drive axle between the leveling valves. I believe the function is to provide air to each of the brake chambers. There are air lines running to each chamber from this valve. Mine is leaking out of the top. Not enough that the bus won't build air(close though) but enough that the brakes don't aways release properly. It only feels like a screw or something of that nature on the top of the valve, which seems strange to me as I would have expected the valve to leak out of the bottom where there appears to be an exhaust port. Anyway if someone can help that would be great. Thanks | ||
| Mark Renner (Boomer)
Registered Member Username: Boomer Post Number: 88 Registered: 11-2006 Posted From: 66.174.79.241  Rating: N/A |
Rear brake relay valve. | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1220 Registered: 12-2000 Posted From: 76.68.120.61  Rating: N/A |
If it has four hoses to your brake chambers, it is the inversion valve for the DD3 system. Mounted right at the differential? happy coaching! buswarrior | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 207 Registered: 3-2007 Posted From: 76.4.151.87 Rating: N/A |
just a thought, The reason for air leaking out maybe you have a brake diaphram bad and it is leaking back thru the valve,????? | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 22 Registered: 10-2007 Posted From: 207.161.143.46 Rating: N/A |
Thanks for the help, yes Buswarrior it is located right on top of the diff. I suppose a diaphram could be bad causing it to leak back through. Is there a test I can do? I was thinking the valve is probably cheaper that the pod so I would start there. Should I just try pinching the air lines off one at a time to see if there is air coming back through. It leaks weather the brakes are apply or released. Thanks again. | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1222 Registered: 12-2000 Posted From: 76.68.122.140 Rating: N/A |
Hello Grant The inversion valve is fed a constant supply, so if it is leaking as you describe, it is defective. Depending on the age of the hoses, you may have to replace them, if the fittings have corroded such that they won't come apart without twisting around. If they give you any trouble, just cut them and wind the debris out. Take the pieces with you to get them made up the right length at any heavy vehicle jobber. happy coaching! buswarrior | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 24 Registered: 10-2007 Posted From: 207.161.143.46 Rating: N/A |
Excellent!! Thanks Busswarrior, that all make complete sense to me now. The hoses actually look in surprisingly good condition. You obviously have had alot of experience with these MCI's I'll probably be looking for more advice regarding the heating system and charging system. Thanks again. | ||
| Rob A (Otto)
Registered Member Username: Otto Post Number: 5 Registered: 12-2007 Posted From: 24.109.144.204 Rating: N/A |
Grant, looking in my parts book an inversion valve is 4g-29-1.. 98.00 rebuilt.. but the kit is 17.00 to repair.... an r12 brake relay valve 4g-11-1 (4 hoses) is $60.00 and mci has none in stock... just replaced one on my d3... probably a different #, but..I could check with my parts guy to see if there is an aftermarket available.. check with Fort Gary they probably have what your lookin for Rob | ||
| Rob Norgren (Robsedona)
Registered Member Username: Robsedona Post Number: 39 Registered: 11-2007 Posted From: 70.210.150.118  Rating: N/A |
R12 brake relay valve is a truck part you can get them at truck parts just make sure its the right sides for your valve. And cheaper to boot then MCI or bus parts I got one from a shop in Flagstaff for $35.95 had to bring the old one to match it up. | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 25 Registered: 10-2007 Posted From: 207.161.165.94 Rating: N/A |
Thanks again guys, sure do appreciate all the info!!! I'll take mine off and see if I can match it up at the local truck repair shop, if not I'll try Fort Gary, thanks for that tip Rob , never thought of them. Have a great day! | ||
| Tony LEE (T_lee)
Registered Member Username: T_lee Post Number: 26 Registered: 11-2007 Posted From: 90.56.175.15 Rating: N/A |
"Is there a test I can do" Usual way is to squash each of the lines in turn and see when the leak stops. The diaphragm on that side is faulty. MCI say to actually disconnect each line in turn and see which one has air coming out, but squashing the lines is quicker |