Chevrolet 70 Series 1970, Service Manual

Page: 433 / 841

53 AND 71 SERIES DIESEL ENGINES 6C-36
1 Vibration Damper
Cone
2 Front Cover
3 Oil Seal
4 Gasket
5 Crankshaft
10 9 8
6
Oil Slinger
7 Pump Drive Gear
8
Pump Driven Gear
9 Pump Idler Gear
10 Dowel
Figure 28—Crankshaft Front Cover Mounting
2. Place new gasket at bolting flange of crank­
shaft front cover and attach to engine with w a sh ers
and b o lts. Do not fully tighten b olts until all bolts
have been started and threaded in until bolt heads
contact w a sh ers, and the dam per hub rear cone
h as been in sta lled . (See step 3. below:)
3. Apply engine o il on o il se a l lip and on
dam per hub rear cone, then in sta ll cone with ta p er-
TIGHTEN COVER BOLTS
1 THROUGH 7 IN ft
NUMERICAL SFQUENCE
Figure 29—Front Cover and Damper Cone
Installation and Bolt Tightening Sequence
ed end of cone pointing toward front end of crank­
shaft (fig. 29).
4. Following sequence shown in figure 29,
tighten 3 /8 -2 4 bolts to 25 to 30 foot-pounds torque,
and 1 /2 -1 3 bolts to 80 to 90 foot-pounds.
5. Install engine o il pan with new gask et.
6
. Install damper hub front cone, then in sta ll
crankshaft pulley k eys, pulley, retain er w ash er,
and bolt. Tighten bolt to 290 to 310 foot-pounds
torque with torque wrench.
CRANKSHAFT FRONT OIL SEAL
REPLACEMENT
(WITHOUT REMOVING FRONT COVER)
The method d escrib ed below may be used in
som e in stan ces to rep lace a crankshaft front oil
se a l without rem oving front cover from engine:
REMOVAL
1. Rem ove fan (if crankshaft mounted), pulley
and damper (on In -lin e en gin es). R efer to p roced ­
u re p reviou sly given under "Vibration Dam per,
Front Cover and Oil Seal" and follow applicable
in stru ction s to rem ove crankshaft pulley and damp­
er hub.
2. Using a sm a ll bit, d rill two d iam etrically
opposite h o les in the o il se a l casin g.
3. Thread two sh eet m etal sc r e w s with a flat
w asher on each one into h oles in se a l, then using
two sm a ll pry b ars under the w a sh ers, fo rce the
se a l a ssem b ly outward from front co v er.
IMPORTANT: Be carefu l not to damage the
bore in co v er .
INSTALLATION
1. C arefully clean any old sealant from bore
in front co v er.
2. Apply thin coat of sealant to outer diam eter
of new se a l a ssem b ly . A lso, apply a coat of clean
g r e a se to lip of oil s e a l.
3. With the lip of se a l pointed toward engine,
sta rt se a l a ssem b ly into bore of front co v er. Using
a hollow tube a s a driving tool against outer diam ­
eter of s e a l, tap the sea l a ssem b ly evenly until
flush with the outer face of front co v er.
4. On In-line engines in sta ll vibration damper
on crankshaft, following in stru ction s p reviou sly
given under "Vibration Dam per, Front C over and
Oil Seal." Start the pulley straight and true on
crankshaft.
5. A ssem b le pulley retaining p arts and fan
a ssem b ly (when used). C orrect torque for pulley
retaining bolt is 290 to 310 foot-pounds.
Follow recom m ended p roced u res covering testin g, inspection, and
adjustm ents for b est r e su lts.
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL