Chevrolet 70 Series 1970, Service Manual

Page: 230 / 841

REAR SUSPENSION 4-17
until bearing a ssem b ly (
1 2
) i s free of housing.
3. Insert screw d r iv er in drive slo t of screw
(fig. 24); then rem ove bearing lock nut (13) and
b earing with snap ring (12). D rive screw a s s e m ­
bly (
2 0
) can then be lifted out of housing.
4. R em ove the two lock nuts (19) from sw itch
te r m in a ls (17). Pull off m otor w ir e s (fig. 25).
5. Rem ove three sc r e w s and lock w a sh ers (1)
which attach m otor cover (4) to housing. P ull out
m otor (
6
) with cover (4) attached to m otor (fig.
26). with two c o v er nuts (2). Grommet (7) can
then be rem oved.
6
. Rem ove two jam nuts (9) and fiber w a sh ers
(10) from outside of housing. On inside rem ove
sw itch to housing sc r e w s (18). Pull out autom atic
sw itch (17) a s shown in figure 27.
7. Do not d isa sse m b le torsion spring (23),
and spring winding le v e r (
2 2
) u n le ss n e c e ssa r y to
replace one of the p a rts. If n e c e ssa r y to d is­
a sse m b le , mount a ssem b ly in v ise as shown in
figure 30. P lace a sh ort p ie ce of rod in hub of
spring winding le v e r a s a safety factor to prevent
injury should torsion spring slip out of control.
N ext, p lace two lengths of tubing over ends of
spring, pull spring ends apart, then r a ise spring
above spring winding le v e r (fig. 31). To assem b le;
r e v e r s e above procedure.
CLEANING AND INSPECTION
Clean a ll parts except m otor in cleaning s o l­
vent. Inspect as follow s:
Autom atic Switch
The sw itch a ssem b ly is se r v ic e d only a s an
a sse m b ly . The sw itch should have clean free
m oving points which c lo se firm ly under spring
tension.
D rive Screw
The d rive scre w i s se r v ic e d only as an a s ­
sem b ly. While holding nut, rotate screw from one
end to the other. It should rotate freely . When
nut r ea ch es either end of the scre w , screw should
continue to turn, and nut should not jam or turn
off the ends.
E le c tr ic Motor
The m otor (serv iced only a s an assem b ly) is
r e v e r sib le . With the m otor housing connected to
one battery term inal, and eith er one of the two
m otor w ir e s connected to the other battery te r ­
m inal the m otor w ill run in one d irection. With
the other m otor w ire connected to the battery,
m otor w ill run in the opposite direction.
The m otor has a sta ll torque of approxim ately
6
in .-lb s . Clamp a sm all c r e sc en t w rench on the
rectangular drive on the arm ature shaft. P lace
m otor in v is e , and grasp w rench handle with one
Figure 28—Disassembling Torsion Spring From Lever
hand. Connect one m otor w ire to a battery te r m i­
nal and connect m otor housing to the other battery
term in a l. The wrench should tend to turn with a
torque of about
6
in .-lb s . Allow w rench to turn
VERY SLOWLY, making sure that th is pull or
torque i s p resen t the FULL 360 d eg r e e s turn of
the wrench. If one arm ature is burned out, the
torque w ill disappear for a sm all part of the 360
d e g r e e s. Do not overheat the m otor w hile making
te s t. Motor m ust be replaced as an a ssem b ly , and
is lubricated for life of m otor. The m otor used is
1 2
-v o lt type which is the sam e a s truck e le c tr ic a l
sy stem . When in stallin g a new m otor u se care
to s e le c t m otor of proper voltage. Voltage is
stam ped on m otor housing and side cover of
sh ift unit.
M iscellan eou s P a rts
G askets should be replaced at a ssem b ly .
Inspect bearing. If b a lls are rough or chipped,
rep lace with new bearing and snap ring a ssem b ly .
Pack bearing a ssem b ly with clean grea se (C hassis
G rease) - Symbol “ C” in LUBRICATION (SEC. 0).
Inspect torsion spring (25, fig s . 21 and 29) for
breaks or w ear at le v e r contact points. Make
certain that co r r e ct replacem ent spring is used.
ASSEMBLY OPERATIONS
(EATON AXLES)
Key num bers in text r efer to figure 21.
1. Install autom atic sw itch assem b ly (17) into
housing. U se flat head screw (18) to attach sw itch
to housing. On outside of housing, in sta ll two
bushings (11), fiber w a sh ers (10), and jam nuts (9)
over sw itch term in al sc r e w s. Tighten nuts firm ly.
2. In stall m otor a ssem b ly grom m et (7), then
in sta ll gasket (5) on housing. Install m otor (
6
) and
cover (4) into housing. Install three sc r e w s and
lock w a sh ers (1) and two stop nuts (2). Install
m otor cover cable clip (3) under outer screw .
Tighten sc r e w s and nuts firm ly.
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL