GMC 4000 Series Service Manual page 154

Figure 4 — Rem oving Rubber-Type Eye Bushing
4. Open vise slowly and carefully to let spring
assem bly expand. Wire brush and clean spring
leaves.
5. Replace weak or broken spring leaf.
6. Align center bolt holes in spring leaves
using a long drift.
7. Compress spring leaves in a vise, then re­
move drift and install a new center bolt.
8. Install nut on center bolt and tighten s e ­
curely. Peen end of bolt to prevent nut from loos­
ening.
9. Align springs by tapping with a hammer.
Install spring clip, bolts, spacers, and nuts.
SPRING EYE OR RADIUS LEAF BUSHING
REPLACEMENT (WITH SPRINGS REMOVED)
Steel Backed Rubber Bushings
Remove and replace radius leaf eye bushing
using bushing remover and installer (J-21058 Tool
Set) as shown in figures 3 and 4.
REAR SPRING INSTALLATION
(Refer to Figs. 1, 2, and 3)
1. Set spring assembly and tapered shim or
spacer (if used) at axle pad.
IMPORTANT: Tapered shim must be installed
on axle in same position that was noted at removal.
NOTE: If auxiliary springs are used, place
spring assembly and spacer in position.
2. Install U-bolt spacer over center bolt.
3. Seat U-bolts in spacer grooves, then s e ­
cure spring to axle by installing anchor plates,
shock absorber bracket (when used) and nuts on
U-bolts. Tighten nuts to torque listed in "Speci­
fications" at end of this section.
4. On "E," and "S" Series, lower frame until
spring enters hanger with spring eye and hanger
hole aligned at front and spring touches cam sur­
face of hanger at rear.
5. On 4000 and PS4500 Series, lower frame
until ends of spring enter the hanger and touch the
cam surface of hanger. Compress radius leaf with
G M C S E R V I C E M A N U A L
J-2 1 0 5 8
REAR SPRINGS AND SUSPENSION
Figure 5 — Installing Rubber-Type Eye Bushing
a C-clamp (fig. 3) until radius leaf eye and hanger
holes are aligned.
6. On 4000 and PS4500, torque nut to torque
listed in "Specifications." On "E," and "S" Series,
torque the eye bolt to torque listed in "Specifica­
tions."
7. On 4000, and PS4500 Series, remove C-
clamp from radius leaf.
8. On 4000, and PS4500 Series, install re­
bound pin at front and rear hangers. Install re­
bound pin retainer and secure with retainer bolt.
9. On "E," and "S" Series, install rebound
bolt, washer and nut at rear hanger. Tighten re­
bound bolt nut to torque listed in "Specifications."
10. Install wheels.
11. Remove blocking and lower frame to place
weight on springs. Check U-bolt nuts for proper
torque. Refer to "Specifications."
CAUTION
U-bolts must be retightened to initial
torque listed in "Specifications" after 500
m iles when new, or if spring repairs are
made.
AUXILIARY SPRINGS
Some vehicles have auxiliary rear springs
which are necessary for certain types of oper­
ation. When used, the auxiliary spring leaves or
leaf (Single Leaf Auxiliary) are installed above the
regular rear spring assembly and are held in place
by long U-bolts. Brackets are installed on frame
and are contacted by the auxiliary spring to pro­
vide added stability required for these unusual
conditions.
SHOCK ABSORBERS
Shock absorbers (when used) are non-adjust-
able and non-repairable. Maintenance operations
Sec. 4B
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