Chevrolet 10 Series 1968, Service Manual, Page: 326 / 713

BRAKES 5-83
Installation
1. Mount valve securely with mounting nut and lock
washer.
2. Check and clean air lines to valves.
3. Connect air lines to their proper ports on the valve.
4. Perform "Operating and Leakage Checks" as out­
lined in this section.
DD3 SAFETY ACTUATOR (Fig. 119)
Rem oval
1. Block and hold vehicle by some means other than air
brakes.
20 With the actuators in the released position, discon­
nect or completely remove air lines from parking
and service ports of the actuator.
C A U TIO N :
A ir will be exhausted out the line
that is connected to the parking port when the
control valve is operated. If this line is not re ­
moved, it should be disconnected in such a way
that it will not whip and cause damage as the air
exhausts.
NOTE: After disconnecting only the parking
and service port lines, operate the parking con­
trol valve. This action will exhaust the isolated
air supply and air from the locking port. As a
safety precaution, the service system should
also be drained, if it is separate.
3. Disconnect air line at actuator lock port.
4. Remove yoke pin cotter pin and knock out yoke pin.
5. Remove mounting nuts, then actuator.
Disassem bly (Fig. 119)
NOTE: Clean actuator exterior of all road
grime then mark it in such a way so it can be
assembled in the same manner.
1„ Remove yoke and yoke locknuts.
2. Remove boot, splash guard and felt breather.
3. Remove auxiliary and service clamping ring nuts
and bolts.
1. Piston Grommet
18. A u x ilia ry Clam p Ring
2. Piston
19. Nut and Bolt
3. C o l lar
20. A u x ilia ry Diaphragm
4. Rollers (8)
21. Service Pressure
5. Spring Seat Washer
Plate
6. Rol ler Spring
22. S e rvice Clam p Ring
7. Lock Cap
23. Nut and Bolt
8. Retaining Ring
24. S e rvice Diaphragm
9. C ap Screw 25. Push Plate and
10. Push Rod
Shaft Assembly
11. Boot
26. Return Spring
12. Splash Guard
27. Shaft Bearing
13. Locknut
28. T— Bo It
14. Cotter Pin
29. Non-Pressure Plate
15. Yoke 30. Felt Breather
16. Yoke Pin 31. Mounting Nut and
17. A u x ilia ry Pressure Plate Lock Washer
4. Spread clamping rings slightly, just enough to slip
them off the plates. It may be necessary to use a
soft mallet driver to break the clamping rings loose.
If the rings are being reused, caution should be taken
against bending them out of shape.
5. After clamping rings are removed, auxiliary pres­
sure plate, auxiliary diaphragm, service pressure
plate and service diaphragm are removed in that
order.
6. Place the remains of actuator on a smooth surface
with the push plate down.
3 1 1
F ig . 119-Exploded View of DD3 Safety Actuator
CHEVROLET TRUCK SERVICE MANUAL