GMC 4000 Series Service Manual page 234

PUSH-PULL VALVE
CONTROL
PORT
PISTON
INVERSION VALVE
DD3 BRAKE ACTUATOR
SERVICE
PORT
PARKING AND
EMERGENCY PORT
G M C S E R V I C E M A N U A L
CONTROL PORT
INLET VALVE SEAT
INLET
VALVE
SUPPLY
PORT
EXHAUST
VALVE SEAT
INLET-EXHAUST
VALVE
INLET-EXHAUST
EMERGENCY
VALVE SEAT
RESERVOIR
PARKING
DIAPHRAGM PORT
SHAFT
PISTON
RAMP
COLLAR RAMP
ROLLER
SPRING
LOCK PORT
RELAY A N D
Q U IC K R E ­
LEASE V A LV E
Figure 1 9 — Schematic D ia g ra m of D D 3 Brake Actuator System
m | | RESERVOIR
EXHAUST VALVE
[
EXHAUST PORT
PORT
PARKING RESERVOIR
SERVICE RESERVOIR
BRAKE
A P P L IC A T IO N
V A LV E
Sec. 5B
Page 227
AIR BRAKES
j ATMOSPHERIC
AIR SUPPLY SOURCE
T-l 190-1