Chevrolet 70 Series 1970, Service Manual

Page: 654 / 841

TRANSMISSIONS AND CLUTCHES 7-55
MASTER CYLINDER REPLACEMENT
(CONVENTIONAL CAB MODELS)
R em oval
1. P la ce a su itab le container under m aster
cylin d er to catch fluid when hydraulic lin e i s d is ­
connected. DO NOT RE-USE THIS FLUID.
2. D isconnect hydraulic line from outlet of
clutch cylin d er.
3. P ull push rod boots off m aster cylin d er
tube which extend through dash. Boot w ill rem ain
on push rod when m a ster cylinder is rem oved.
4. R em ove th ree b o lts and lo ck w a sh ers at­
taching m aster cylin d er to dash (nuts a re w elded
to inner sid e of dash) and rem ove m a ster cylinder
a ssem b ly .
Installation
1. P la c e gasket o v e r cylinder tube. P o sitio n
m a ster cylinder a ssem b ly at dash, w hile an a s s i s t ­
ant in sid e cab guides push rod into p iston . Attach
cylin d er to dash w ith th ree b olts and lock w a sh ers.
Tighten b olts firm ly .
2. Connect hydraulic lin e s to clutch cylinder
ou tlet.
3. Inside cab, p la ce push rod boot over end of
cylin d er tube.
4. Adjust push rod as p rev io u sly d irected
under "M aster C ylinder Push Rod Check and Ad­
justm ent."
MASTER CYLINDER REPLACEMENT
(STEEL TILT CAB MODELS, EXCEPT
TM80 AND TV70)
R em oval
1. P la c e a su itab le container in sid e cab under
the m a ster cylin d er to catch fluid when hydraulic
lin e i s disconnected.
NOTE: DO NOT RE-USE THIS FLUID.
2. D isconnect hydraulic lin e from m aster c y l­
inder and p lace a su itab le cap over lin e to prevent
entry of dirt into hydraulic sy ste m .
3. R em ove attaching p arts retaining m aster
cylinder to fir e w all and rem ove unit from v e h icle.
Installation
1. In stall new or- rebuilt m a ster cylinder on
fir e w all. Tighten attaching p a r ts firm ly .
2. R em ove p ro tectiv e cap from hydraulic lin e
and connect lin e to m a ster cylin d er.
3. Adjust stop sc r e w as d escrib ed p reviou sly
under "Clutch P edal Stop S crew Adjustment."
4. F ill m aster cylinder and bleed sy ste m as
d escrib ed p reviou sly under "Bleeding Hydraulic
System ."
MASTER CYLINDER REPAIR
The follow ing p roced u res cover d isa ssem b ly ,
cleaning, in sp ection and rep a ir, and a sse m b ly of
com ponents u sed in the clutch cylinder b ore. R efer
to applicable m a ster cylin d er illu stra tio n .
D isa sse m b ly
1. Clean a ll dirt from outside of unit, u sin g a
n on -p etroleu m solven t.
2. R em ove snap ring from groove in cylinder
b ore.
3. R em ove p iston a sse m b ly , prim ary cup,
return sp rin g and reta in er a ssem b ly from clutch
cylin d er b ore.
4. R em ove co v er from cylin d er housing.
Cleaning
Im m erse a ll p a rts in denatured alcoh ol and
w ash thoroughly. Wipe s m a ll p a rts dry and blow
out in sid e of r e s e r v o ir and cylin d er b o re. Make
su re intake and b ypass p o rts in cylinder housing
and b leed er h o les in p iston a r e clean .
CAUTION: DO NOT use kerosene or
gasoline for cleaning master cylinder
components.
Inspection and R epair
M aster cylin d er rep a ir k its a r e available
w hich contain a ll the p a rts ordinarily required
when se r v ic in g m a ster cy lin d e r s. R efer to applic­
able P a r ts Book fo r part number of rep air k it. In
addition to rep lacem en t of p a rts contained in r e ­
p air kit, m a ster cylin d er should be in sp ected and
rep aired , if n e c e s s a r y , a s follow s:
1. Exam ine cylin d er b ore. If sc o r e d o r ru st­
ed, recondition by honing. B e su r e to u se proper
s iz e hone. Clutch cylin d er b ore is 1 -1 /8 -in c h . Do
not hone m ore than n e c e ssa r y to rem ove s c o r e s
and sm ooth up cylin d er. R em ove b u rrs caused by
honing from around b y -p a ss and intake p o r ts.
1 Bleeder Valve
2 Fluid E ntry Port
3 Cylinder Body
4 Push Rod Boot
5 Push Rod
6 Piston Retaining Ring
7 Piston
8 Piston Seals
«•»
Figure 27—Clutch Slave Cylinder
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL