I have a 1977 IH Transtar 4200, when the parking brakes are applied they don't immediately set. There is no gush of air under the truck, instead the air blows out the exhaust port of the dash valve, it probably takes around 15 seconds for the air to stop and the brakes set. If I hold the service brake to the floor then pull the parking brake valve there is only a short burst of air out the valve maybe one second long before the brakes set. I was thinking maybe my quick release valve is bad or do I have something else going on? Thanks
Correct-more than likely a bad QR-1 valve. Or it doesn't have one because someone removed it.
It has one right above the rear axle. Must be bad