TM 9-2330-238-14
1-7. LOCATION AND DESCRIPTION OF MAJOR COMPONENTS (Con’t).
AIR/HYDRAULIC BRAKE SYSTEM
Key
Component
Description
19
Service Air Line
Receives compressed air from towing vehicle for braking purposes
during towing operation.
20
Relay Valve
Directly controls the service brakes. Receives air from service air line
which causes relay valve to release compressed air from air reservoir.
21
Airbrake Chamber
Receives air from air reservoir and actuates master cylinder.
22
Master Cylinder
Provides hydraulic pressure to move wheel cylinders in wheel brake
mechanisms.
23
Filler Caps
Provide access hole for filling master cylinder with brake fluid.
24
Wheel Cylinder
Receives brake fluid from master cylinder and applies pressure to
brake linings. Fitted with a bleeder valve at rear of cylinder to permit air
to be bled from the system.
25
Air Reservoir
Stores compressed air to apply semitrailer chassis brakes. Equipped
with a draincock for draining moisture and releasing air pressure if
brakes are locked.
26
Air Filters
Prevent moisture and foreign material from passing through air
system. Contain removable elements. Pipe plug at bottom of air filter
may be removed to drain moisture.
27
Emergency Air Line
Receives compressed air from towing vehicle to engage emergency
brakes.
28
Air Couplings
Connect emergency and service air lines of semitrailer to towing
vehicle.
TA701888
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