Section XI. CARRIER AIR BRAKE RELAY VALVE ASSEMBLY
The carrier air brake relay valve assembly is located
in the carrier air brake system between the air receiver
tanks and the rear air brake chambers. The relay valve
speeds up the application and release of the rear wheel
brakes. It is controlled by the brake control valve and
keeps the air pressure in the rear brake chambers the
same as the pressure being delivered by the brake
control valve. The relay valve reacts to even slight
changes in pressure, and raises, lowers, or completely
exhausts the air pressure in the rear brake chambers.
Air pressure from the brake control valve is delivered to
the cavity above the diaphragm. As this cavity is
comparatively small and very sensitive to quick changes
in air pressure, the action of the relay valve in changing
its delivered pressures is also very rapid.
375. Carrier Air Brake Relay Valve Assembly
Removal and Disassembly
a. Removal. Remove the carrier air brake relay
valve assembly (TM 5-3810-207-20).
b. Disassembly. Disassemble the carrier air brake
relay valve assembly in numerical sequence as
376. Carrier Air Brake Relay Valve Assembly
Cleaning, Inspection, and Repair
a. Cleaning. Clean all parts with an approved
cleaning solvent and dry thoroughly.
b. Inspection and Repair. Inspect all parts for
excessive wear and damage. Replace or repair all
377. Carrier Air Brake Relay Valve Assembly
Reassembly and Installation
a. Reassembly. Reassemble the carrier air brake
relay valve assembly in the reverse of the numerical
b. Installation. Install the carrier air brake relay
valve assembly (TM 53810-207-20).
Screw, cap, 3/16-24 x
3/8 in (2 rqr)
Plug, pipe, 1/8 in.
6 Name plate
7 Mounting plate
Figure 103. Carrier air brake protection control valve
assembly, exploded view.