Steering Column (C And; Collision D Ia G N O S - Chevrolet 1977 light duty truck Service Manual

DIAGNOSIS C AND K STEERING COLUMNS
This section contains diagnostic inform ation to help
locate the cause of the problem in the column. Reference
should be m a de to the correct method o f column
disassembly, repair, adjustm ent and reassembly. D a m ­
aged, broken or deform ed parts must be replaced with
the correct replacement.
G E NER AL IN F O R M A T IO N
All C a n d K models are equipped with function
locking e n e rg y a b so rb in g
columns are o f five basic designs as follows:
- The synchromesh column is
1. Synchrom esh
used on models with the standard transmission and
column m ounted shift levers. The shift tube, within the
outer column jacket, includes two lower shift levers for
connection to the transmission control linkage.
2. - This column is used on models
Floor S hift
equipp ed with a m anual transmission with the shift lever
on the floor. This column does not incorporate a shift
tube.
3 A U T O M A T IC T R A N S M IS S IO N
column shift only, Locks the transmission and steering
wheel while in park position and the lock cylinder is in
"L o ck " position.
4.
T IL T W HEEL O P T IO N
steering shaft o f this column is specifically designed to
accom m odate the optional tilt steering wheel. It is
available with either m anual (the fourth column type) or
autom atic transmission on (the fifth column type).
To p erform diagnostic procedures on the steering
colum n upp er end components, it is not necessary to
remove the column from the vehicle.
T he steering wheel, horn components, directional
signal switch, ignition switch and lock cylinder may be
removed with the column re m ain in g in the vehicle as
described in the Service M anual u nder "C om p on ent Part
Replacem ent".
The outer m ast ja c k e t shift tube,
C A U T IO N :
steering shaft a n d instrum ent panel m ounting
bracket are designed as energy absorbing units.
Because o f the design o f these components, it is
absolutely necessary to handle the column with
care when perform ing any service operation.
A vo id hammering, jarring, dropping or leaning
on any portion o f the column. When reassem­
bling the column components, use only the
specijied screws, nuts a n d bolts a nd tighten to
specified torque. Care should be exercised not
to use over-length screws or bolts as they m ay
prevent a portion
compressing under impact.
COLLISION DIA G N O S IS
To determ ine if the energy absorbing steering
column com ponents are functioning as designed, or if
repairs are required, a close inspection should be made.
An inspection is called for in all cases where dam ag e is
S teering Colum ns. T he
- Available with
- The upper end and
o f the colum n from
evident or whenever the vehicle is being repaired due to
a front end collision. W henever a force has been exerted
on the steering wheel
components, inspection should also be made. If dam age
is evident, the afftected parts must be replaced.
The inspection procedure for the various steering
column components on C and K trucks is as follows:
Column Support Bracket
D am age in this area will be indicated by separation
of the m ounting capsules from the bracket. The bracket
will have moved forward toward the engine co m pa rt­
ment and will usually result in collapsing o f the jacket
section o f the steering column.
C O LUM N JACKET
Inspect jacket section o f column for looseness, a n d /
or bends.
SHIFTER SHAFT
Separation o f the shifter shaft sections will be
internal and cannot be visually identified. Hold lower
end o f the "shifter sh aft" and move "shift lever" on
column through its ranges and up and down. If there is
little or no movement of the "shifter shaft", the plastic
joints are sheared.
Steering Shaft
If the steering sh aft plastic pins have been sheared,
the shaft will rattle w hen struck lightly from the side and
some lash m ay be felt when rotating the steering wheel
while holding the rag joint. It should be noted that if the
steering shaft pins are sheared due to m inor collision
with no appreciable dam age to other components, that
the vehicle can be safely steered; however, steering shaft
replacement is recom mended.
Because o f the differences in the steering column
types, be sure to refer to the set o f instructions below
which apply to the column being serviced.
M E TH O D TO D E T E R M IN E CO LUM N
COLLAPSE
Measure distance between top o f neutral-start switch
window opening and the bottom o f the upper jacket. The
correct value is shown below:
a. C-Truck 5 11/16" to 5 1/2".
b. K-Truck 5 11/16" to 5 1/2".
STEERING C O LU M N ELECTRICAL
ANALYZER J -2 3 9 8 0 FOR C AND K SERIES
CO LUM NS
A new tool has been
technician analyze the steering column wiring harness
for electrical problems. The tool in actuality eliminates
the steering column, related wiring and components; and
replaces them with the tool itself. In this way disassembly
or steering column, or
developed to help
its
the