Chevrolet 70 Series 1970, Service Manual

Page: 491 / 841

ENGINE COOLING SYSTEM 6K-24
Figure 41 —Removing Retaining Ring
w ith Special Tool (J-4646)
c. P la ce the adhesive w asher in the im p elle r
bond a r e a with the ce ram ic in s e rt on top. The
polish ed face of the c e ra m ic in s e rt should be v is­
ible to the a sse m b le r (fig. 41).
d. Clamp the c e ra m ic in s e rt and im p elle r
to g eth er with a 3 /8 ” bolt and nut and two sm ooth
1 /8 " thick flat w a sh e rs. Tighten the bolt to 10 foot­
pounds torque.
CAUTION: DO NOT mar polished
surface of the ceramic insert.
e. P la ce im p elle r assem b ly in a level position,
w ith ce ram ic in s e rt up, in an oven p re -h e a te d to
350°F ., and bake the assem bly fo r one hour.
NOTE: The face of the ce ram ic in s e rt m ust be
sq u a re with the ax is of the tap ered b o re within
0.004". The pump shaft may be used a s a m andrel
fo r th is inspection.
f. Remove the im p e lle r from the oven and
a fte r it has gradually cooled to room te m p e ra tu re ,
in sta ll it in the pump. Do not loosen and rem ove
clam ping bolt and w a sh e rs until assem bly cools.
6. Make s u re the m ating su rfa ces of the w ater
s e a l and the ceram ic in s e rt on the im p elle r, a r e
f r e e of d irt, m etal p a rtic le s , and oil film . Then,
in sta ll the im p elle r on the sh aft. P lace the w ash er
and lock nut on the shaft; tighten the nut to 45 to 50
foot-pounds to rqu e.
7. Loosen the clam ps and rem ove the hose
fro m the w ater outlet opening of the pump.
8. In s e rt a fe e le r gauge into the w a te r outlet
opening of the pum p. The m inim um clearan ce b e­
tween the im p elle r and the pump housing m ust be
0.015".
9. Use a new gasket and in sta ll the w ater
pump cov er. Tighten the nuts o r bolts sec u rely .
NOTE: When the cover is se c u re d by cadm ium
plated bolts with nylon in s e rts , inspect them c a r e ­
fully to m ake s u re the nylon in s e rts a r e in p lace
and p ro tru d e sufficiently beyond the th re a d s to
pre v en t leakage. Under no circ u m sta n ces should a
stan d ard bolt be used.
10. In stall and s e c u re the hose on the w ater
outlet opening with the clam ps.
W ater Pump Rem oval
1. D rain the cooling sy stem .
2. Remove the ra d ia to r, fan shroud and fan, if
n e c e ssa ry .
3. Loosen the hose clam ps and rem ove the
hoses fro m the pump housing.
4. Remove the pump housing-to-engine fro nt
cover mounting b olts and detach the pump. Use
c a re to prev en t dam age to the g ea r teeth when d is ­
engaging the pump g ea r fro m the cam shaft g ear.
W ater Pump D isassem bly
1. T urn the pump g ea r so the slo t is over the
ends of the bearin g retaining rin g , in s e rt p lie rs
(J-4646) into the slo t and with th e aid of a sm all
sc re w d riv e r rem ove the ring fro m the groove
(fig. 41).
2. Remove the pump cover and gasket.
3. Hold the g e a r sec u rely and rem ove the
im p elle r nut and w asher.
CAUTION: While holding gear, use
care to prevent damage to the gear teeth.
4. Use p u lle r (J-4794-01) to rem ove the im ­
p e lle r.
5. P r e s s the shaft, b ea rin g s, and pump g ea r
assem b ly out of the pump housing.
6. P la c e the g ea r on the bed of an a rb o r p re s s
with the shaft extending downward, then place a
s h o rt piece of 5 /8 " d iam eter b a r stock between the
shaft and ra m of the p r e s s and p r e s s the shaft out
of the g ea r a s shown in fig u re 42.
7. Support the shaft assem b ly on in n er ra c e
of the la rg e r b earin g with the th read ed end down.
P la c e flat stock between the ra m of p r e s s and the
shaft and p r e s s the pump shaft out of the la rg e
bearing .
8. In v ert the shaft, support it on the in ner ra c e
of the sm a ll b earing and re p eat the p ro c e s s d e s­
crib ed in Step 7.
9. If n e c e ssa ry , rem ove w a te r sea l a s d e s­
crib ed p reviously under "W ater Seal R eplacem ent."
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL