| Author |
Message |
Ted Schuler (Red4501)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 27, 2005 - 10:12 am: | |
HELP!!!!!
I started up my Cruiser after sitting for a year. I know way too long.....
I got the batteries built back up an bus started but would not build air pressure. Also would not go into fast idle (maybe due to air press..
When I went to shut it down from Up in the drivers seat it would not respond to the switch I had to go back and cut off the fuel to the blower.
The engine is a DD 8V71 in my GMC 4501 Scenicruiser. I found a small air leak and put on a temporary fix. Still no pressure is building. I heard some pressure but very little (less than 10 psi). Any suggestion. I have to move the bus verry soon.
Thank you in advance for any help,
Red4501Tx |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 27, 2005 - 10:58 am: | |
dd2 air govenor on air compressor...looks kinda like a little box with a rocket ship coming out of it....new one is about 20.00 at any truck supply & larger truck stops |
Rodger in WA
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 27, 2005 - 10:59 am: | |
This from a non mechanic:
Probably the relief valve is stuck open or you have a massive leak. Some pressure on the gauge indicates the compressor is trying to build pressure. At low idle, the compressor isn't building pressure very fast. Maybe revving the engine to 1500 RPM or so for a while might help unstick the valve if that's the culprit.
High idle and shutoff require air pressure to the shut off valve and high idle valve and electricity to operate the "Skinner Valves" which direct air to the high idle a and shutoff valves. No air = no high idle or shut off.
Hope that helps.
You'll probably need to get under the bus to find the leak or stuck valve. |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 27, 2005 - 11:01 am: | |
sorry........D2 air govenor |
Brian Brown (Fishbowlbrian)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 27, 2005 - 11:40 am: | |
You can air up your system with a shop compressor. You'll have better luck tracking down leaks w/o the noise of the big Detroit.
If your air gauge is like mine, it's plumbed from the aux. tank and won't register pressure until the brake system gets up to 65psi. A relatively small leak in this system, especially at idle speeds on the compressor, can keep the aux. system from ever getting air. Also, the valve that prevents the air from entering the aux. side until 65psi could be stuck shut.
Lots of possible leaks or valves can be causing this. Also, could be compressor or air gov., as suggested. You could pull the air line off the comp. to quickly rule that in or out.
Hopefully you have an air system schematic from 'Da Book.
Keep us posted!
BB |
Brian (Bigbusguy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 27, 2005 - 1:00 pm: | |
Take off the intake hose or air fiter on the compressor if air is going in its going out some place if its flutering in and out it probley the governer. Just hold your hand on the intake when it running and you will find out what its doing.
Brian 4905 Klamath Falls Oregon |
Ted Schuler (Red4501)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 27, 2005 - 7:24 pm: | |
I back pressured the system with a shop compressor and found my leak. It is my left rear tag axle brake cylinder. I have removed it and will be taking it to the shop tomarrow and see if they can repair it. Thank you for all your suggestions. I will keep you updated on my progress. |
Buswarrior (Buswarrior)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 01, 2005 - 11:38 am: | |
Hello Ted
A leaking brake chamber should not prevent the bus from airing up. There's only supposed to be air pressure in the brake chamber when you push down on the brake pedal.
If you have no air leaks, and no air pressure building, as well as Two Dogs suggestion of a stuck/faulty air compressor governor, if you have an air dryer, its purge valve may be stuck in the unloaded position, blocking the air compressor's efforts to fill the system. See if the compressor is getting hot when it is running. Cold, it isn't pumping. Hot, something's plugged.
Common problem up here in the cold country. The heating element or wiring on the air dryer fails, the purge valve freezes in the unloaded position, and then when the governor calls for more air, the purge valve won't return to the loading configuration. Basically, no air can get by the dryer. Compressor gets hotter than blazes, as it keeps on building the air pressure in the line between it and the dryer to the heavens.
Let us know how you are making out!
happy coaching!
buswarrior |
Ted Schuler (Red4501)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 05, 2005 - 9:58 pm: | |
Well, I'm back at it again. The compressor head is getting hot but still the bus is not airing up. Is the govner attached to the compressor or is it possibly located some where else? |