Need help! W900A service brake

Hi,
my name is Barbara, living in Germany and I´m new in this forum. Excuse my bad english...

A couple of years ago, I bought an W900A from PA and shipped it to Germany. I like this old W900 Kenworth-types!
Now it´s a little bit difficult to get informations, parts and experiance for this old American trucks here in Europe. Mostly, I helped me by myself, and I think, that I did a good job to built it up.
However, since some weeks the exhaust of food-valve is leaking - and this is bad...

That´s what happend:

- engine is running.
- the compressor blow up the air-system.
- 130 psi, the air-dryer release the air to 120 psi. It´s working well.
- service brake is working also, it´s ok, because the compressor do his job. Basicly, the truck is ready to ride.

but:

- engine-stop: the airpressure is going down to 0 psi in 5 minutes by the exhaust from food-valve.
- press down the pedal very sensibility for a little short way - the air don´t leak anymore.
- release the pedal, air leaks continue.

Hey, guy´s, what´s going on?

Thank´s or help!
Barbara

 

Hello Brian,

thank you, I just thought about it, too, but I wasn´t sure. The next question is about the right part-number... The original ist almost painted and dirty, so there is no anymore sticker on it.

Thank´s
Barbara

 

Thank you, in the next couple of days I get the valve from the truck to have a better look for any ID-numbers.
If the problem is localize it, I give a short reply.

Barbara