Chevrolet 70 Series 1970, Service Manual

Page: 490 / 841

ENGINE COOLING SYSTEM 6K-23
Figure 38—W ater Pump
Components
I8V-71 Engine)
b ea rin g s a r e used to c a rry the shaft. The la rg e r
b ea rin g is u sed at the d riv e g e a r end of the shaft
to accom m odate the th ru s t load (fig. 38).
An oil se a l is located in fro n t of the s m a lle r
b earin g and a sp rin g -lo ad ed face type w ater sea l
is used behind the im p e lle r. The im p elle r in c o r­
p o ra te s the ce ram ic s e a t fo r w ater sea l.
W ater Seal R eplacem ent
The w a te r se a l can be rep laced without re m o v ­
ing the pump if the ra d ia to r, fan and fan shroud
have been rem oved.
1. Remove the pump cover and gasket (fig^38).
2. Remove the nut and w ash er and withdraw
the im p e lle r with p u lle r (J-4794-01).
CAUTION: Use care to prevent dam­
age to the ceramic impeller insert. Place
the impeller on the bench with insert up.
3. Use w a te r pump s e a l re m o v e r s e t (J-22150)
to rem ove the se a l with the pump on o r off the
engine (fig. 39).
a. P la ce the se a l p u lle r (J-22150-2) over the
se a l and into the two slo ts in the pump body casting.
b. P o sitio n the sleev e (J-22150-4) o ver the
s e a l p u lle r to support the sea l p u lle r.
c. In se rt the slo tted en d o fth e a rm (J-2 2 1 5 0 -5 )
through the se a l p u lle r and position the cover stud
in the slot of the a rm a s shown in fig u re 39.
d. With the sq u are head screw s ta rte d in the
tapped hole of the s e a l p u lle r, fing er-tig h ten the
sc re w sufficiently to hold the a rm in position.
e. Remove the se a l by turning the screw
clockw ise.
4. P la ce a new w a te r se a l on the shaft. P r e s s
o r tap the s e a l into the s e a l cavity with a suitable
sleev e which has an inside d iam eter la rg e enough
to fit around the s e a l and r e s t on the b r a s s c a r t­
rid ge lip.
Figure 3 9 —Removing W ater Seal from Pump
5. Inspect the ce ram ic im p e lle r in s e rt fo r
c ra c k s , s c ra tc h e s , and bond to the im p e lle r. If in­
s e r t is dam aged, re p la c e it in following m anner:
a. Bake the u sed ce ram ic in s e rt and im p elle r
assem b ly at 500°F., fo r one hour to rem ove the
c e ra m ic in s e rt and w ire b ru sh the im p eller bond
a r e a to rem ove the old adhesive, oxide, sc a le , etc.
The ce ram ic in s e rt can be rem oved easily from
the counterbore while the adhesive is hot.
b. Wipe the im p e lle r bond a r e a and the groov­
ed side of the new ce ram ic in s e rt with a cloth
soaked in a common solvent such a s alcohol. Wipe
clean with a dry cloth.
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL