Chevrolet 10 Series 1968, Service Manual, Page: 227 / 713

REAR SUSPENSION AND DRIVE LINE 4-58
Checking For Leakage
1. Build up air pressure in system to maximum pres­
sure limit (100 to 105 lbs.). Place lock control knob
in “ LOCK” position.
2. Coat all air line connections with soap suds to check
for leakage. No leakage is permissible. Leakage
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 headings.
Control Valve (Fig. 106)
Removal
1. Disconnect cable assembly at control lever (4).
2. Disconnect air outlet line at control valve outlet
port (12).
3. Disconnect check valve fitting from valve inlet port
(
11
).
4. Disconnect connectors at switch assembly.
Disassembly
1. Remove tell tale lamp switch.
2. Using a small drift, drive fulcrum pin (3) from con­
trol lever (4) and remove lever.
3. Remove cap nut (10), cap nut O-ring (9), valve spring
(8), and valve (7).
4. Push against stem of control valve plunger (14) to
remove plunger through top of control valve body.
Remove plunger spring (13).
5. Remove “ O” rings (9) from cap nut (10) and plunger
(14).
Cleaning and Inspection
1. Wash all parts except “ O” rings in cleaning fluid.
2. Inspect all parts for wear, replace if damaged in any
way.
3. Check tension of valve spring. If not within limits
listed in “ Specifications” replace with new spring.
Assem bly
1. Install new plunger “ O” ring (9) on plunger (14), and
new cap nut “ O” ring (9) on cap nut (10).
2. Install plunger return spring (13) on plunger (14)
then install assembly in valve body.
3. Coat fulcrum pin (3) and control lever cam (4)
lightly with chassis lubricant. Position control lever
(4) in valve body and install fulcrum pin. Stake edge
of fulcrum pin hole in valve body to hold pin in place.
4. Position new valve (7) and valve spring (8) in valve
body (6) and install cap nut (10). Tighten nut firmly.
5. Install tell tale lamp switch.
Installation
1. Position control valve on mounting bracket and in­
stall two screws.
2. Connect control cable to control lever.
3. Connect air inlet and check valve fittings.
4. Connect tell tale lamp connectors to switch.
5. Check system for leaks and proper operation.
Air Shift Cylinder
A piston type shift cylinder is mounted on forward rear
axle torque divider case cover. Piston rod is connected
to sliding clutch. As air pressure is applied to piston,
sliding clutch is shifted into locked position. When air
pressure is exhausted from shift cylinder, spring pres­
sure returns sliding clutch to unlocked position.
Shift cylinder should be removed, disassembled, and
the piston seals replaced whenever leakage is indicated
at the cylinder.
Differential Lockout
Removal and Installation
Removal and installation instructions may be found in
the “ Truck Overhaul Manual” under “ Vacuum Operated
Lockout” or “ A ir Operated Lockout.”
PROPELLER SHAFTS, UNIVERSAL JOINTS
AND BEARING SUPPORTS
INDEX
Page
General D e s c r ip t io n ............................................................. ...4-58
Maintenance and A d ju stm en t................................................ ...4-59
Component P art R e p la c e m e n t............................................. ...4-60
P ro p e lle r S h a f t s ................................................................
R e m o v a l............................................................................. ...4-60
Inspection . .
Disassembly
Assembly .
Installation . ,
Page
4-60
4-60
4-60
4-61
GENERAL DESCRIPTION
Tubular type propeller shafts and needle bearing type
universal joints are used on all model trucks. An inter­
nally splined sleeve which compensates for variation in
distance between rear axle and transmission is located at
the forward end of single or rear propeller shafts (fig.
107).
The number of propeller shafts used is dependent upon
the wheel base of the vehicle. On vehicles which use two
or more propeller shafts, each shaft (except the rear) is
supported near its splined end in a rubber cushioned ball
bearing which is mounted in a bracket attached to a frame
crossmember. The ball bearing is a permanently sealed
and lubricated type.
CHEVROLET TRUCK SERVICE MANUAL