Steering Column - GMC 1976 ZEO 6083 Maintenance Manual

CAUTION: All column fasteners are important attaching parts in that they could
affect the performance of vital components and systems, and/or could result in
major repair expense. They must be replaced with parts of the same part num-
bers or with equivalent parts if replacement becomes necessary. Do not use
replacement parts oflesser quality or substitute design. Torque values must be
used as specified during re-assembly to assure proper retention of these parts.
GENERAL INFORMATION AND
OPERATION
The function locking energy-absorbing steering
column includes three important features in addition
to the steering function:
I. The column is energy-absorbing, designed
to compress up to 8.25 inches in a front-end collision
to minimize the possibility of injury to the driver of
the vehicle.
11 . The ignition switch and lock are mounted
conveniently on the column.
111. With the column mounted lock, the igni-
tion, steering and gearshifting operation can be
locked to inhibit theft of the vehicle.
The function locking energy-absorbing steering
column assembly is used on all vehicles . When a
vehicle is being driven, the forward movement of the
vehicle and the forward movement of the driver both
constitute a form of kinetic energy . When a vehicle
is involved in a frontal collision, the primary force
(forward movement of the vehicle) is suddenly
halted, while the secondary force (the driver) contin-
ues its forward direction . A severe frontal collision
generally involves these two forces-the primary and
the secondary forces . Thesecondary impact occurs
when the driver is thrust forward onto the steering
wheel and column .
The function locking energy-absorbing column is
designed to absorb these primary and secondary
forces to the extent that the severity of the secondary
impact is reduced .
The tilt function locking columns are designed
for ease of entry and driver comfront . These columns
have six or seven different steering wheel angle posi-
tions.
The tilt mechanism consists of an upper and
lower steering shaft assembly with a universal joint
between them . A support assembly is held to the
STEERING COLUMN
STEERING 9- 4 1
mast jacket by a lock plate, and a hearing housing
assembly is positioned over .the upper steering shaft
and secured to the support by two pivot pins . Two
lock shoes are pinned to the housing assembly and
engage a pin in the support assembly . When the
release lever is pulled up and the lock shoes disen-
gage the support pin, the steering wheel is pushed up
by a spring compressed between the support and
housing assemblies .
The operation of the lock is the same as in other
GM vehicles . To start the vehicle, you insert the key
in the lock, turn the unit clockwise to "start" and let
the switch return to the "on" position . The "off',
"lock" and "accessory" positions are also the same
as in other GM vehicles When you engage the
shift lever in "park" and lock the ignition, the steer-
ing wheel locks and the gearshift locks.
The function locking energy-absorbing column
may be easily disassembled and reassembled. The
serviceman should be aware that it is important that
only the specified screws, bolts and nuts be used as
designated and that they are tightened to their speci-
fied torque . This precaution will insure the energy
absorbing action of the assembly . Overlength bolts
should not be used, as they may prevent a portion of
the assembly from compressing under impact .
Equally as important is correct torque of bolts and
nuts . Care should be taken to assure that the bolts or
nuts securing the column mounting bracket to the
instrument panel are torqued to the proper specifica-
tion in order that the bracket will break away under
impact .
When the column is removed, special care must
be taken in handling this assembly . Only the speci-
fied wheel puller should be used . 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 . It is, therefore, impor-
tant that the removal and installation and the disas-
sembly and reassembly procedures be carefully
followed when servicing the assembly .