NEED HELP !!!

I re-read your first post. You said air is escaping from the front of the valve? You mean out of the dash or from inside the dash?

I did a little more thinking on it. With the tractor brakes released, the exhaust port on the yellow park valve should be closed off. If it only does it with the brakes released and not when the park brake is applied, I'd say your new valve is shot.

 

If its escaping out around the knob and based on what you've told us, my best guess is the park valve. Bear in mind that this is just my educated guess.

 

I agree with @NorthernMechanic it's the valve. The quality of parts has really took a dive.

I misunderstood as well and thought it was leaking out the back

 

Sometimes if you spin the knob or jiggle it you can sometimes stop or slow down the leaks too. Make sure you mark those lines well before you remove them from the valve. It could be a royal PITA to install the new one if you don't.

 

I had an 84 that had factory cruise. Was an option for sure.

 

I'm curious as to how air powered cruise works on a mechanical engine? Would be cool to put that on my KW.

 

just make sure you mark all the air lines going to that thing or its a mess trying to make it right again. personal experience here