Description; Diagnosis Of The Steering Column - GMC 1986 P-Truck Service Manual

3B4-2 STEERING COLUMN
The locking energy absorbing steering column in­
cludes three important features in addition to the
steering function:
1. The column is energy absorbing, designed to
compress in a front-end collision to minimize the
possibility of injury to the driver of the vehicle.
2. The ignition switch and lock are mounted conve­
niently on the column.
3. With the column mounted lock, the ignition,
steering and gearshifting operation can be locked
to inhibit theft of the vehicle.

DIAGNOSIS OF THE STEERING COLUMN

PROBLEM
Lock System Will
Not Unlock
Lock System Will
Not Lock
Lock System—High
Lock Effort
10. Ignition switch mounting bracket is

DESCRIPTION

POSSIBLE CAUSE
1. Lock bolt damaged.
2. Faulty lock cylinder.
3. Damaged housing.
4. Damaged or collapsed sector.
5. Damaged rack.
1. Lock bolt spring is broken.
2. Damaged sector tooth.
3. Faulty lock cylinder.
4. Damaged housing.
5. Damaged rack.
6. Interference between the bowl and
coupling.
7. Ignition switch stuck.
8. Actuator rod restricted or bent.
9. Transmission linkage adjustment is in­
correct.
1. Lock cylinder is faulty.
2. Ignition switch is faulty.
3. Rack preload spring is broken or weak.
4. Burrs on the sector, rack, housing,
support, tang of the shift gate or actua­
tor rod coupling.
5. Bent sector shaft.
6. Distorted rack.
7. Misalignment of the housing to the
cover (tilt only).
8. Distorted coupling slot in the rack (tilt
only).
9. Bent or restricted actuator rod.
bent.
The column may be disassembled and reassem­
bled. To insure the energy absorbing action, it is impor­
tant that the specified screws, bolts and nuts be used
only as designated and that they are tightened to the
specified torque.
When the column is removed from the vehicle, such
actions as a sharp blow on the end of the steering
shaft or shift lever, leaning on the column assembly, or
dropping of the assembly could shear or loosen the
plastic fasteners that maintain column rigidity.
CORRECTION
1. Replace the lock bolt.
2. Replace or repair the lock cylinder.
3. Replace the housing.
4. Replace the sector.
5. Replace the rack.
1. Replace the spring.
2. Replace the sector tooth.
3. Replace the lock cylinder.
4. Replace the housing.
5. Replace the rack.
6. Adjust or replace.
7. Adjust or replace.
8. Adjust or replace.
9. Adjust.
1. Replace the lock cylinder.
2. Replace the ignition switch.
3. Replace the spring.
4. Remove the burrs.
5. Replace the shaft.
6. Replace the rack.
7. Replace either or both.
8. Replace the rack.
9. Straighten or replace the rod.
10. Straighten or replace the bracket.