Chevrolet 1977 light duty truck, Руководство по обслуживанию

Страница: 203 / 861

DIAGNOSIS C AND K STEERING COLUMNS
This section contains diagnostic in fo rm atio n to help
locate the cause o f the problem in the column. Reference
should be m a d e to the correct m ethod o f column
disassembly, repair, adjustm ent and reassembly. D a m ­
aged, broken o r d eform ed parts must be replaced with
the correct replacement.
G E N ER A L IN F O R M A T IO N
All C a n d K models are e quipped with function
locking e n e rg y a b s o rb in g S te e rin g C olum ns. T h e
colum ns are o f five basic designs as follows:
1. Synchrom esh
- T he synchrom esh column is
used on models with the s tan d ard transmission and
colum n 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.
Floor S h ift
- This column is used on models
eq u ip p e d with a m a n u a l transm ission 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 - Available with
colum n shift only, Locks the transm ission and steering
wheel while in park position and the lock cylinder is in
" L o c k " position.
4. T IL T W H EEL O P T IO N - The u pper end and
steering sh aft 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 e rfo rm diagnostic procedures on the steering
colum n u p p e r end components, it is not necessary to
rem ove the colum n from the vehicle.
T h e steering wheel, h orn components, directional
signal switch, ignition switch and lock cylinder may be
rem oved with the column r e m a in in g in the vehicle as
described in the Service M anual u n d e r " C o m p o n en t Part
R eplacem ent".
C A U T IO N :
The outer m ast ja c k e t shift tube,
steering sh a ft a n d instrum ent p a n el 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 v o id ham m ering, jarring, dropping or leaning
on any portion o f the colum n. When reassem­
bling the column components, use only the
specijied screws, nuts a n d bolts a n d tighten to
specified torque. Care should be exercised not
to use over-length screws or bolts as they m ay
p reven t a portion o f the colum n fro m
compressing under impact.
COLLISION D IA G N O S IS
T o d eterm 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 d a m a g e is
evident or whenever the vehicle is being rep aired due to
a front end collision. W henever a force has been exerted
on the steering wheel or steering column, or its
components, inspection should also be made. I f d am ag e
is evident, the afftected parts must be replaced.
T he inspection procedure for the various steering
column com ponents on C and K trucks is as follows:
Column Support Bracket
D am ag e in this area will be indicated by separation
o f the m ounting capsules from the bracket. The bracket
will have moved forward toward the engine c o m p a rt­
ment and will usually result in collapsing o f the jacket
section o f the steering column.
C O L U M N JACKET
Inspect jacket section o f column for looseness, a n d /
or bends.
SHIFTER SHAFT
Sep aratio n o f the shifter shaft sections will be
internal and cannot be visually identified. Hold lower
end o f the " s h ifte r s h a ft" and move "shift lever" on
column through its ranges and up and down. If there is
little or no m ovem ent o f the " s h ifter shaft", the plastic
joints are sheared.
Steering Shaft
If the steering sh a ft 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 in o r collision
with no appreciable d am ag e to other components, that
the vehicle can be safely steered; however, steering shaft
replacem ent is recom m ended.
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 T H O D TO D E T E R M IN E C O LU M 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 L U M N ELECTRICAL
ANALYZER J -2 3 9 8 0 FOR C AND K SERIES
C O L U M N S
A new tool has been developed to help the
technician analyze the steering column w iring harness
for electrical problems. The tool in actuality eliminates
the steering column, related w iring and components; and
replaces them with the tool itself. In this way disassembly