84 Eagle no air for brakes

[Texasjack]

My 84 Eagle model 10 6v92 T with 740 Allison, started great yesterday ,but would build no air pressure to release brakes. Where do I start to look for my problem? thanks !!

[richard5933]

Not trying to be a wise guy here, but you start at the beginning.

Start by the compressor and make sure it's making air, then work forward looking/listening for a leak. If the compressor is pumping air, you should be able to hear it if it's a big enough leak to keep air from building.

There are a few pneumatic controls in the engine bay, so follow the air lines to those and listen for leaks.

If you have an air dryer, make sure the discharge/vent/purge valve isn't stuck open. Check at the axles listening for air bag leaks and brake line leaks.

In the dash and under the driver. (Wiper valves and brake treadle)

Check tanks for holes/rust/leaking drains.

[Ed Hackenbruch]

If you have a ping tank make sure it isn't plugged up. That will keep air from building.

[chessie4905]

First question. Was it below 32° overnight?

[wildbob24]

Eagle = no air bags. Other than that, what Richard said.