Help ID a leaking part on an A1's brake system

[htxol]

I'm tackling some leaks on my air system. Attached is a photo of some bubbles coming off a valve attached to the side of the Anti-Compounder for the rear axle. The truck has set for about 30hrs and it is still bumbling. I don't see this valve in any of the TMs - although most of the TM I can find are for the pre-A1.

Can you ID this part? And maybe its function?

Also attached is a flow diagram to show the ins/outs. There are 3 that I can't ID. I assume:
+ 1 is the parking break release from the cab,
+ 1 is air the secondary trundle on the break
+ 1 ??

Really appreciate any help IDing these. Thanks!

 

[Suprman]

I believe that is a pressure protection valve.

 

[htxol]

Thanks. That's what I thought at first based on location. But the flows don't seem to match. I'd expect the PPV to have and output back to the trailer connections, but both of these seem to run towards the front of the truck.

 

[NDT]

Maybe tractor protection valve.

 

[htxol]

Bit more information. I pulled the valve. It looks like it is some variant of a Bendix TR3 inversion valve. Not what I expected given that the "standard" inversion valve in place to the driver's side of the Anti-Compounder

The part number on the side is 5004546 or 7883.

Appreciate any thoughts or if anyone has seen similar.

Thanks

 

[NDT]

Take it to Houston Truck Parts on Wayside and chances are you will walk out with a new one.

 

[Asymair95]

While you are back there make sure your vents are not clogged up with mud nests. Both of mine were clogged solid and I had a strange air leak. Cleaning the vents fixed it.

 

[htxol]

While you are back there make sure your vents are not clogged up with mud nests. Both of mine were clogged solid and I had a strange air leak. Cleaning the vents fixed it.

Will do!

 

[htxol]

Little more tracing. Found the protection valve. It is by my air dryer, just inside the frame.

 

[htxol]

I reached out to Bendix - they confirmed that it looked like their valve but said they couldn't match the part numbers. The guys at MME sorted me out with one. Photo attached.

Also replaced the braided air line off the compressor back to the dryer which was in sad shape.

Seems to be holding air much better now. I would loose ~40 PSI over a 24 hour period. Now the truck can sit up for a week and I'm still above 90 PSI. It is nice to not have the compressor load on a cold engine start.

There may be an intermittent leak with the Trailer Air Supply valve on the dash, but will wait until I clean up the interior to tackle that one.

 

[coachgeo]

I reached out to Bendix - they confirmed that it looked like their valve but said they couldn't match the part numbers. The guys at MME sorted me out with one. Photo attached.
...

Glad you found a working solution.

So what is the proper part number then? future readers would like to know. Also what is the popular name(s) for it so folk can search with the right terms when they need one.

thanks in advance

 

[htxol]

Wish I had one. Best I have is the number in the photo, but that doesn't seem to provide any solutions with a search.