Need Repair Help

[glenn_reid]

My air system works, but has a constant leak that is coming from the part pictured. It's not a slow leak, it's almost as though a fitting is missing, but there's no threading on the hole the air is coming out of.

I was thinking I would just replace this part, but I can't seem to locate one like it. Does anybody know what it is, exactly, and what a suitable replacement might be? It's on the back of the cab and the trailer supply lines (red/blue) come out the top. I think it's a tractor protection valve but I'm not exactly sure what all the in/out lines are so I want to replace it with the exact same valve, if possible, or else I need to learn a lot more about air brakes and know exactly what I'm doing, which will take a lot longer!

Thanks,

Glenn Reid

[theakerstwo]

Make sure that the glad hands ant connected together. Then if it still leaks then replace it. i have heard those valves are hard to find but can not beleive that is is not some were. It is a tractor protection valve.There is a later valve that can be used but that means some more replumbing and a different valve in the dash.

[Rob]

Make sure that the glad hands ant connected together. Then if it still leaks then replace it. i have heard those valves are hard to find but can not beleive that is is not some were. It is a tractor protection valve.There is a later valve that can be used but that means some more replumbing and a different valve in the dash.

Hi Glenn, it is a TP-2 and is obsolete since about 1981. There are always some on ebay however. They are common to leak from the bleeder hole.

Rob

[ThaddeusW]

That valve is called the tractor protection valve. It cuts the service line (blue) in case of a trailer break away so you can still safely stop the tractor.

The valve should be able to be replaced with a Bendix TP-3DC.

The three lines toward the bottom are as follows:

Two come from the foot pedal primary and secondary circuits.

The Third line is the air supply line that is fed from the red trailer supply knob in the cab.

[glenn_reid]

Thanks, everybody. Great info, and I was able to find a good replacement part. I appreciate the time you took to reply, and the specific information. Very helpful!