QUICK RELEASE VALVES AND DIFFERENTIAL QUICK RELEASE VALVE
Figure 3 - Midland Differential Quick Release Valve
Figure 4 - Quick Release Valve (Basic) (Bendix QR-1)
NOTE - In some special applications, a spring and spring
seat will be found In quick release valves.
DIFFERENTIAL QUICK RELEASE VALVE
The differential quick release valve operates identically to
the quick release valve except that the air pressure at
the brake foot valve port (Figure 6) must rise to the
pressure level set by the spring in the valve before air
can flow to the brake chamber(s).
The air pressure in the brake chamber is always less
than the pressure in the air line of the foot valve by the
amount it takes to operate the differential valve.
In IH trucks this valve is found on the CO and COF 9670
and 9370 and is mounted on all axles. It is set at 41 kPa
(6 psi) + 10 kPa (1-1/2 psi) by the spring selected and is
not adjustable.
Figure 5 - Quick Release Valve (Basic) (Midland)
Figure 6 - Differential Quick Release Valve (Midland)
All of these valves are serviced in the same manner, with
some minor exceptions that are noted.
CTS-4079A-CHAPTER V - Page 3
