QR1 and pressure regulator valve repairs

I discovered a couple of air leaks after running the bus a week ago.  Ordered parts and the arrived Friday.  So Saturday I worked on the bus attempting to fix the air leaks.  First is this quick release valve which, in this case, is part of the parking brake system.  It resided up front in the spare tire compartment behind the bumper.  Luke at U.S. Coach sent me the rebuild kit which consisted of a diaphragm and a gasket.  Other than laying the the compartment on your back removing the QR1 valve was not difficult nor was dismantling it and replacing the two parts. However, in reading the maintenance manual it mentions a spring and diaphragm seat and my valve clearly did not have these parts.  After I reinstalled the valve I aired up the system and it STILL leaks out the exhaust port with the parking brake applied.  Not sure what my next step is going to be.  I wonder if I have a leak somewhere else in the parking brake system and it just happens to leak back through the exhaust port of the QR1 valve.  I'm still researching.


After finishing the QR1 valve, I removed, rebuilt, and reinstalled the pressure regulator for the blower belt tensioner.  Here is a picture of it NOT blowing bubbles after the rebuild.  Only problem is, it STILL leaks too, just not as bad.  No nest of bubbles, just leaking out the tiny weep hole in the back.  I am researching that one too, but feel that the problem may be a leaking tensioning air cylinder and it comes out the weep hole.  Hopefully I can update with the fix soon.  The regulator is at the top of the picture and the air cylinder on the right side.

Air leaks

Today was the first chance I've had to do anything to the bus in a couple of weeks.  I have started it the past two Sundays and moved it around the lot a bit just to stir fluids up, but that has been it.

Last Sunday I noticed that after I shut down the engine I could hear lots of air leaking from under the front.  So today I started poking around with my soapy water bottle to see what I could find.  Found a fitting or two that needed tweaking but the big culprit was the silver square thing in the picture.  Later found it is a quick release valve (a part of the air brake system) and it is leaking out of the side.  A call to Luke and U. S. Coach told me what it was and he is sending me a rebuild kit for it.

For some time I've had a leaking pressure regulator for the blower belt tensioner but I had no idea it was leaking this bad.  While soaping down fittings, I came to the engine compartment and inspected a few.  The regulator is leaking hugely as you can see by the large bubbles it blew.  Luke has the rebuild kits in stock for this too and is sending it to me.