Bendix Air Valves:

[Rob]

Well I sprung for all three new valves in the cab for my 73 RL. I got two PP-1 valves, and a PP-7 valve cause they all leak when actuated although they perform their intended functions, (I think).

I spent some of yesterday at the shop testing the various relay, quick release, tractor protection and air diaphragm functions on the truck. I pulled the pilot line from the rear mounted relay valve, (R-5, I think) and when depressing the brake valve shot a stream of oil about 2 ft.!! Well I know that just aint right so I started disconnecting the air line at the compressor and it is dry, and clean. The compressor itself is a reman unit and it appears that when it was replaced the air lines and tanks were not blown clean. Best I can tell this residual oil is from the compressor mounted prior. The main line to the relay valve did not have any oil content at all. I then took the line loose at the foot valve and it appeares to be clean also. I then got out my blow gun with suction hose and rinsed the hose out with denatured alcohol till it was clean. That is the only line that had oil in it. The wet tank has oil in it and has been drained but not cleansed it internally. Plan to do that in the future.

Let me see if I understand these functions correctly: The PP-1 valve, (yellow handle) that releases the tractor brakes charges both the PP-1, (blue handle), and the PP-7 (red handle) with supply air. My PP-1 with the blue handle does not need to be manually pushed in to release tractor brakes. After air is built up through the PP-1, (yellow handle) the red handle can be pushed in to charge the trailer glad hands via the TP-3 valve. Currently the PP-7 valve leaks so severely it has to be manually held in for at least 30 seconds before it will remain pushed in and the leak slows.

I soaped nearly every single connection under the truck and on the engine with 150 psi of shop air applied to the tanks and no leaks at all with the aeroquip hose. The only leaks are under the dash, (best I can tell) and hopefully they will disappear with changing out these valves.

Also had taken the air-o-matic steering cylinder apart earlier and it was loaded with engine oil on both sides of the piston, but the lines to it were clear. The torque valve appears to work properly but I've not used pressure gauges on it yet. Not really sure if it will go back on or not and am currently looking for a p/s setup.

Any errors feel free to post.

Thanks for listening.

Rob

[Rob]

Tonight I replaced the PP-1, and the PP-7 that were leaking. I had to use a known good PP-7 as the new one that I had did not have the proper ports threaded.

It was missing the 1/8th pipe thread on the left side, (looking at from the front).

All functions are working properly with no air leakage, (that I can hear) under the dash any longer.

Rob