Chevrolet 70 1969 Series, Shop Manual

Page: 130 / 913

FRONT SUSPENSION 3C-11
SECTION 3C
FRONT SPRINGS
DESCRIPTION
Front springs on all series vehicles are
semi-elliptic type except for the optional tapered
two-leaf type. Springs are attached to front axle
center with U-bolts and secured at frame side
rails as shown in figure 1. U-bolts may also
secure shock absorbers, tow eyes and power
steering cylinder brackets (when used). Spring
eyes on all models are equipped with replaceable
bushings. The spring shackles on TM-80 models
are
also equipped with replaceable bushings.
Front springs, which employ rubber-mounted
bushings with solid-eye bolt, require no lubrica­
tion at bushing.
GENERAL SPRING MAINTENANCE
LU B R IC A T IO N
Spring leaves (except optional two-leaf type)
are lubricated at time of assembly and require no
further lubrication unless spring is disassembled.
Shackle and bracket pins or bolts are equipped
with lubrication fittings. Fittings are also pro­
vided in the shackles on TM-80 models to provide
lubrication of shackle bushings. Spring eye bush­
ings that are rubber-mounted do not require
lubrication.
Refer to L U B R IC A T IO N (SEC. 0).
T IG H T E N IN G
At regular intervals, spring U-bolts should
be checked and tightened if necessary to torque
listed in "Specifications" at end of this section.
IM P O R T A N T : U-bolts must be kept T IG H T at
all times to hold axle in place at springs. Other­
wise, axle may shift, causing misalignment; also,
spring leaf failure in the vicinity of the spring
center bolt could result.
The center bolt serves only to hold the spring
together while in shipment and during installation,
and as a locating point when assembling spring to
axle. After assembly, it is strictly the function of
the U-bolts to hold the spring and axle in align­
ment, and the importance of keeping the U-bolts
tight cannot be overemphasized.
N O T E : Spring leaves of the optional two-leaf
type are held in alignment by raised nibs at the
normal center bolt position.
Check, and tighten if necessary, all spring
shackle or bracket bolt nuts and shackle or bracket
pin clamp bolts. Rebound clips should be tightened
just enough to hold spring leaves in alignment with­
out restricting free movement of leaves.
REPAIR OPERATIONS
F R O N T SPRING R E M O V A L (Refer to Fig. 1)
All Conventional and Tilt 70 Models
1. Raise vehicle frame to take weight off
spring. Make sure vehicle is supported safely.
2. Support axle on floor jack, remove nuts at­
taching shock absorber at spring bracket.
3. Remove spring shackle U-bolt nuts, then
lower axle.
4. At front of vehicle, remove spring eye bolt
nut and washer; withdraw eye bolt from bracket
and spring eye.
SERVICE DIAGNOSIS CHART
C O N D IT IO N
POSSIBLE C A U SE
C O R R E C T IO N
Spring Noise
1. Loose U-bolts.
2. Loose or worn shackle bushings.
3. Lack of lubrication.
4. Defective shock absorber.
1. Tighten to recommended torque.
2. Replace shackle bushings.
3. Lubricate as required.
4. Replace shock absorber.
Spring Sag or
Bottom
1. Inoperative shock absorbers.
2. Broken spring leaf.
3. Severe operation or overloading.
1. Replace shock absorbers.
2. Replace leaf or spring Assy.
3. Check load capacity rating.
Spring Breakage
1. Loose U-bolts.
2. Normal fatigue.
3. Overloading.
1. Tighten to recommended torque.
2. Replace spring.
3. Check load capacity rating.
CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK S H O P M A N U A L