Chevrolet 70 1969 Series, Shop Manual

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FRONT SUSPENSION 3A-3
not return to the normal operating position due to
the tires gripping the floor surface when the vehicle
is lowered on the jack.
IMPORTANT
"TO E - IN " M E A S U R E M E N T S M U S T
BE M A D E A T T H E H O R I Z O N T A L AXIS
O F T H E W H E E L .
"Toe-in" is corrected by loosening clamp
bolt at tie rod ends, then turning tie rod with pipe
wrench until wheels have proper toe-in.
NOTE
On vehicles with power steering,
loosen power cylinder to tie rod brac­
ket U-bolt nuts.
With both tie rod ends in same plane, tighten
clamp bolts securely. Toe-in should be 1/8 to 1/4
inch.
With power steering, tighten power cylinder to
tie rod bracket U-bolt nuts. Adjust power cylinder
as directed in " P O W E R S T E E R I N G " (SEC. 9B) of
this manual.
FRONT WHEEL CAMBER
Camber is the amount in inches or degrees
that front wheels are tilted outward at top from
vertical position (see " C ," fig. 1). Camber offsets
wheel deflection, due to wear of front axle parts,
and prevents a reverse or negative camber condi­
tion. A reverse or negative camber is an inward
inclination of wheels at the top.
If camber is extreme or unequal between
wheels, improper steering and excessive tire wear
will result.
Camber variations may be caused by wear at
wheel bearings and steering knuckle bushings, or
by a bent steering knuckle or axle center.
Specifications are listed at rear of this section.
C H E C K IN G A N D C O R R E C T IN G C A M B E R
Before checking camber, check wear at king
pins as follows:
Jack up front of vehicle, pull bottom of wheel
outward and take a camber reading; then pull top
of wheel outward and take a camber reading. If
readings vary more than 1 /4 °, make following
adjustments:
1. Adjust the wheel bearings as directed in
" F R O N T HUBS A N D B E A R IN G S" (SEC. 3D), then
take camber readings as shown on chart (fig. 1).
If readings still vary over 1 /4 °, replace steering
Figure 2— Method of Checking Frame Angle
knuckle bushings and king pins as instructed in
" F R O N T A X L E " (SEC. 3B).
2. Check the wheel run-out as instructed in
W H E E L S A N D T IRES (SEC. 10) of this manual. If
run-out is excessive, straighten or replace wheel.
3. Place vehicle on level surface, with normal
weight of vehicle on wheels, then take final camber
reading. If camber gauge is not available, readings
can be taken as shown on chart in figure 1. Place
square as shown and measure distances " A " and "B ."
"B " should exceed " A " by amount specified. C a m ­
ber dimensions of right wheel should not vary over
3 /3 2 " from camber dimensions of left wheel. If
final camber reading is incorrect, either steering
knuckle or axle center is bent.
4. To determine which part is bent, check
king pin inclination (D, fig. 1). Camber plus king
pin inclination is the "included angle" of steering
knuckle. If "included angle" of knuckle varies more
than 1 /2 ° from value specified, knuckle is bent
and should be replaced. Excessive positive camber
results in irregular wear of tires at outer shoulder.
Negative or reverse camber causes wear at inner
shoulder. Ease of steering is affected by any devi­
ation from specified camber.
AXLE CASTER
Positive caster is the rearward tilt from the
vertical of the king pin. Negative or reverse caster
is the forward tilt from the vertical of the king pin.
Incorrect caster may result from sagging
springs, bent axle, twisted axle, or uneven tighten­
ing of spring U-bolt nuts. Tighten all U-bolt nuts
equally. Refer to " F R O N T SPRINGS" (SEC. 3C) for
U-bolt torque specifications. Generally, if the axle
is tyisted, the caster will be unequal for right and
left side.
C H E C K IN G A N D C O R R E C T IN G C A S T E R
IM P O R T A N T : Caster, camber, and toe-in di­
mensions are for vehicle carrying its design load
whereby the frame in most instances would be
level. If alignment check is to be made with frame
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L