Chevrolet 30 Series 1967 Service Manual page 210

REAR SUSPENSION AND DRIVE LINE 4-52
the boot from the push rod.
2. Remove the clevis yoke and nut from the push rod
(fig. 95). Remove the screws, nuts, and lock wash­
ers which attach the two halves of the cylinder and
the rubber diaphragm together. Remove the outer
half of the cylinder, and separate the rubber dia­
phragm from the inner half of the cylinder.
3. Install a new diaphragm and push rod assembly in the
rear half of the cylinder.
4. Make certain the mating faces of the cylinder halves
are clean. Position the outer half of the cylinder on
the rubber diaphragm, and install the screws, nuts,
and new lock washers. Install the boot, nut, and
clevis yoke on the push rod.
5. Make certain that the snap ring groove on the inner
half of the cylinder is clean. Position the cylinder in
the bracket on the power divider with the slot in the
rear half of the cylinder at the bottom.
. Install the retaining snap ring and seat it solidly in
6
the groove. Attach the bracket lever to the rod
clevis with a clevis pin and a new cotter pin. Attach
the vacuum line to the locking cylinder. Test the
system for vacuum leaks.
AIR OPERATED
Operation
Air operated differential lock utilizes air pressure
from the air brake system for its operation. Units used
in air-operated power shift system are: Shift Control
Valve, mounted on engine side of dash; check valve, in­
stalled in air line at control valve air inlet; differential
lock shift cylinder, mounted on forward rear axle torque
divider case cover; and interconnecting air lines and
fittings.
With lock control lever (fig. 96) in "UNLOCK" position,
there is no air pressure in differential lock shift cylin­
der. Shift return compression spring holds cylinder
piston and lock linkage in unlocked position.
When lock control lever (fig. 96) is moved to "LOCK"
position, air pressure is admitted behind lock shift cylin­
der piston. As air pressure forces the piston outward,
the differential lock is shifted into locked position.
Checking For Leakage
1. Build up air pressure in system to maximum pres-
I N T E R A X L E
D I F F E R E N T I A L
CK
F ig . 9 6 - D iffe re n tial Lock Control Lever and Plate (Typ ical)
i n
! I N
sure limit (100 to 105 lbs.).
in "LOCK" position.
2. Coat all air line connections with soap suds to check
for leakage. No leakage is permissible.
can sometimes be corrected by tightening the con­
nection. If this fails to correct leakage, disconnect
leaking fitting and replace seal ring around tube
flare.
3. Coat entire surface of lock shift cylinder and control
valve with soap suds to check for leakage. If leakage
is evident in either unit, remove faulty unit and over­
haul as directed under individual heads.
CONTROL VALVE
Control valve (fig. 97) used in "Air-Operated Differen-
Fig. 97 - Sectional V ie w of Control V a lv e (T yp ical)
1. Instrument
Panel
2. Name Plate
3. Fulcrum Pin
4. Control Lever
5. Exhaust Port
6. Body
7 . V a lv e Disc
Place lock control lever
Leakage
8. V a lv e Spring
9. O-ring
10. Cap Nut
11. To Intake M anifo ld
or A ir Tank
12. To Shift C ylin d er
13. Plunger Spring
14. Plunger
CHEVROLET TRUCK SERVICE M ANUAL