Park Brake push pull

[Cary and Don]

Does anybody know the part number and crack pressure for a park brake control valve with spring brakes?  The one Napa is trying to sell is is 40lb crack with 1/8" ports.  Seems like the crack pressure should be higher.

Don and Cary
1973 05 Eagle
GM 4107
Neoplan AN340

[PCC]

I thought the dynamite pressure was closer to 60 PSI.

The lower pressure (40 PSI) would give you more time to find an air leak before the vehicle  rolls further when you are still underneath? (Kidding)

[luvrbus]

Don, 40  lbs is the standard don't worry your spring brakes are set long before the valve pops I prefer the yellow square over the round knob myself

good luck

[Cary and Don]

The reason we are changing it is the park isn't completely setting.  We took the line loose going from the park knob to the park chambers quick release with the park brake set.  There was still air seeping from the line coming from the knob and once the line was loose the brakes got tighter. Hope this fixes it.

Don and Cary
1973 05 Eagle
GM 4107
Neoplan AN 340

[Cary and Don]

Follow up on spring brake, park brake.

We finally got this problem fixed.  After days of replacing the quick release valve, the two way check valve, rear brake chamber, and the push pull park control valve we found out it wasn't any of these. 

We finally took the line loose going to the rear from the push pull knob and put a gauge on it.  With the park brake released the gauge read 80lbs.  With the park brake set the gauge was reading about 8lbs.  Not exhausting completely.  That kept the park brake from setting completely.  Took the exhaust line off the push pull park valve.  The line exhausted.  So a new exhaust line cured the problem.

It never occurred to us that the exhaust line would have been plugged up.  We think it has been this way for years and the PO just thought that this was the way things were.

Hope this information will keep somebody else from spending days and a ton of money trying to figure this one out. Thanks to everyone that helped us along the way.

Don and Cary
1973 05 Eagle
GM 4107
Neoplan AN340