Chevrolet Light Duty Truck 1973 Service Manual page 187

"S N U G -U P THE N UT TO
FULLY SEAT BE A R IN G S—
THIS O V E R C O M E S A N Y
BURRS O N THREADS.
range of front end wheel alignment settings. Neverthe­
less, should settings vary beyond certain tolerances,
readjustment of alignment is advisable. The specifica­
tions stated in column
1
in the specifications section of this manual should be
used by owners, dealers and repairmen as guidelines in
vehicle diagnosis either for repairs under the new vehicle
warranty or for maintenance service at customer's
request. These specifications provide an acceptable all-
around operating range in that they prevent abnormal
tire wear caused by wheel alignment.
Governmental Periodic Motor Vehicle Inspection pro­
grams usually include wheel alignment among items that
are inspected. To provide useful information for such
inspections, the specifications stated in column
aforesaid applicable chart are given and these are well
within the range of safe vehicle operation.
In the event the actual settings are beyond the
specifications set forth in column
applicable), or whenever for other reasons the alignment
is being reset, Chevrolet recommends that the specifica­
tions given in column 3 of the aforesaid applicable chart
be used.
NOTE: A normal shim pack will leave at
least two ( ) threads of the bolt exposed
2
beyond the nut. If two (2) threads cannot be
obtained: Check for damaged control arms
and related parts. Difference between front
and rear shim packs must not exceed .30
inches. Front shim pack must be at least .24
inches.
Caster (Fig. 20)
All caster specifications are given assuming a frame
angle of zero. Therefore, it will be necessary to know the
angle of the frame (whether "up" in rear or "down" in
rear) before a corrected caster reading can be
determined. Camber and toe can be read "as is" from
the alignment equipment.
3. BACK OFF N U T
UNTIL JUST LO O SE
( 1 / 4 - 1 / 2 TURN)
Fig. 18—Wheel Bearing Adjustment
of the applicable vehicle chart
of the
2
or (whichever is
1 2
FRONT SU S PEN SIO N
4. H A N D ' S N U G -U P '
THE NUT
6. W H E N THE BE A R IN G IS PROPERLY
ADJUSTED THERE W ILL BE FROM
. 0 0 1 - . 0 0 8 IN C H ES E N D -PLAY
(LO O S E N E S S ).
How to Determine Caster
1. With the vehicle on a level surface, determine the
frame angle "B" in Fig. 20, using a bubble
protractor or clinometer.
2. Draw yourself a graphic as in Fig. 20 that is
representative of the frame angle (either "up" in
rear or "down" in rear).
3. Determine the caster angle from the alignment
equipment and draw a line that is representative of
the caster reading.
4. To determine an "actual (corrected) caster reading"
with various frame angles and caster readings one
of the following rules applys.
a. A
" DOWN IN REAR"
from a
SUBTRACTED
b. An
" UP IN REAR"
to a caster reading.
POSITIVE
c. A
" DOWN IN REAR
to a
ADDED NEGATIVE
d. An
" UP IN REAR"
SUBTRACTED
reading.
5. Add or subtract as necessary to arrive at the
corrected caster angle.
. Measure dimension "A " (bump stop bracket to
6
frame) and check the specifications for that
dimension.
7. Correct the actual caster angle, as arrived at in Step
4, as necessary to keep within the specifications by
adding or subtracting shims from the front or rear
bolt on the upper control arm shaft (fig.
Camber
1. Determine the camber angle from the alignment
equipment.
3 -1 3
5. LO O S E N N U T UNTIL EITHER HOLE
IN THE SPINDLE LINES UP W ITH
A SLOT IN THE N U T -T H E N
INSERT COTTER PIN.
N O T E : UNDER N O C IR C U M STAN C ES
IS THE B E A R IN G TO BE EVEN
FINGER TIGHT.
frame angle must be
caster reading.
POSITIVE
frame angle must be
ADDED
" frame angle must be
caster reading.
frame angle must be
from a caster
NEGATIVE
).
21
LIGHT DUTY TRUCK SERVICE MANUAL