GMC 4000 Series Service Manual page 481

Sec. 9A
Page 470
MECHANICAL STEERING
1 Lash Adjuster Lock Nut
2 Side Cover
3 Side Cover Bolt
4 Lock Washer
5 Clamp Retainer Screw
6 Back-up Adjuster
(Type 553-D-17 Only)
7 Back-up Adjuster Lock Nut
(Type 553-D-17 Only)
8 Pitman Arm Nut
9 Lock Washer
10 Pitman Shaft
STEERING SYSTEM MAINTENANCE
The following maintenance operations may be
accomplished with the steering gear assembly in­
stalled in the vehicle.
1. At regular intervals, check and if neces­
sary tighten all steering gear mounting bolts, P it­
man arm nut, and gear housing upper cover and
side cover attaching bolts.
2. Lubricate the steering gear and related
linkage as described in LUBRICATION (SEC. 0) of
this manual.
If excess looseness is evident in steering sy s­
tem, all components of steering column should be
inspected for wear. Drag link, connecting rod, and
tie rod end ball sockets should be checked and re­
paired if worn. These checks should be made be­
fore attempting to inspect or adjust steering gear.
If the above checks indicate components to be in
good condition, gear assembly may be adjusted.
4. To adjust steering gear assembly, refer to
"Steering Gear Adjustments" later in this section.
5. Periodically check steering column mount­
ing bolts and check torque on stop clamp, and worm
shaft clamp bolt nuts.
G M C S E R V I C E M A N U A L
11 Pitman Shaft Oil Seal
12 Housing Bushing
13 Steering Gear Housing
14 Pitman Shaft Sector Gear
15 Side Cover Bushing
16 Side Cover Gasket
17 Lash Adjuster Shim
18 Lash Adjuster
19 Expansion Plug
20 Worm Thrust Bearing
21 Ball Guide
Figure I — Type 549-D and 553-D Steering Gear
STEERING WHEEL CHUCKING
OR CLUNKING NOISE
or an up-and-down chucking movement of steering
wheel is encountered, it is possible that upper and
lower mast jacket clamps have loosened and should
be re-torqued. To tighten and adjust steering col­
umn clamps, observe the following:
fire wall.
down movement has been removed.
at fire wall (if used).
shaft to allow 0.012" to 0.015" up and down move­
ment of the upper shaft assembly (fig. 2).
sleeve assem blies should be disconnected, inspect­
ed for wear, and replaced if necessary. This is an
important safety procedure which will prevent
internal steering shaft joint interference.
tempting to determine source of clunking move­
ment in system . Loose linkage, or worn ball joints
22 Adjuster Lock Nut
23 Cup and Adjuster Assembly
24 Adjuster Worm Thrust
Bearing Oil Seal
25 Steering Shaft
26 Upper Worm Thrust Bearing
27 Filler Plug
28 Worm Balls
29 Pitman Shaft Sector Gear
30 Ball Nut
31 Worm Shaft
When steering wheel clunking noise is noted,
1. Loosen mast jacket clamps at dash and
2. Push steering wheel down until all up-and-
3. Tighten clamp at dash; then tighten clamp
4. Adjust "stop" clamp at bottom of steering
NOTE: If "clunking" still exists, the yoke and
Other factors should be considered when at­
T-3332