GMC 4000 Series Service Manual page 468

INSPECTION A N D REPAIR
The following procedures apply to all clutch
components with exceptions as indicated.
CLUTCH RELEASE MECHANISM
1. Check release fork and ball stud for wear,
distortion, cracks or other damage.
2. Check release bearing for roughness or
noise by rotating bearing race while applying light
pressure.
3. Replace all components that would affect
proper operation of the clutch release mechanism.
4. Prior to installation of the clutch release
bearing and support assembly, coat the inside and
outside grooves with a sm all quantity of high
temperature grease. Refer to figure 3.
PILOT BUSHING (IN-LINE ENGINES)
The pilot bushing, which is pressed into
crankshaft is an oil impregnated type bronze
bearing. This bushing requires attention only
when the clutch is removed from the vehicle, at
which time it should be cleaned and inspected for
excessive wear or damage and should be replaced
if necessary.
Removal
Install tool J-1448, and pull bushing from
crankshaft bore (fig. 4).
Installation
In replacing this bearing, use tool J-1522.
Place bearing on pilot of tool with radius in bore
of bearing next to shoulder of tool and drive into
crankshaft.
PILOT BEARING (" V" ENGINES)
Vehicles equipped with a V-6 engine utilize a
pilot bearing which is pressed into the flywheel.
Rouchness or noise can be detected by rotating the
bearing race while applying
Replace bearing if it is rough, noisy, or damaged.
Removal
Remove clutch pilot bearing from engine,
using pilot bearing remover (J -5901-2) with slide
hammer (J-2619). With fingers on puller closed,
insert fingers through bearing inner race as far
as they will go, then tighten thumb screw to
spread fingers. Slide weight sharply against stop
on puller shaft to remove bearing.
Installation
1. Pack clutch pilot bearing with small quan­
tity of high temperature lubricant specified in
LUBRICATION (SEC. 0) of this manual.
2. With shielded side of bearing toward the
rear, drive pilot bearing into position using a
suitable driver. Bearing should be seated firmly.
G M C S E R V I C E M A N U A L
FLYWHEEL
by the clutch facing. This surface must be smooth
and should not be grooved or show deep heat
checks. Replace flywheel if the above conditions
are evident.
DRIVEN DISC
and grease or oil-soaked facings.
broken springs, loose rivets, or cracks in the
driven disc hub. Examine splines in hub for wear
and make sure they slide freely on splines of the
main drive gear.
evident, replace with a new driven disc assembly.
facings are worn or grease or oil-soaked, replace
facings.
PRESSURE PLATE AND COVER ASSEMBLY
the pressure plate and cover assem bly are not
covered in this manual.
hold-down bolts and washers (fig. 2) are installed
in the clutch cover assembly.
cover assem blies, except the GM 11-inch clutch
cover.
wheel with larger exposed portion of disc dam­
per springs toward the rear. While holding driven
disc in place, move clutch cover and pressure
plate into place against the driven disc.
the installing of disc and cover, install cover first
with top of cover against flywheel and bottom to­
light pressure. ward the rear, then raise the disc into position.
Insert alignment tool or old transmission main
drive gear through driven disc hub and into pilot
bearing.
cover and engine flywheel prior to removal, align
these marks.
Tighten bolts alternately one turn at a time to
com press clutch tension springs evenly and pre­
vent possible distortion of cover.
to 35 to 45 foot-pounds torque. Remove aligning
tool.
assembly be sure to remove wood blocks or hold-
down bolts and washers.
release bearing and support assem bly (fig. 3) with
Inspect flywheel surface which is contacted
Inspect driven disc assembly for worn, loose,
If any wear or damage is
If hub and springs are in good condition, but
Detailed inspection and repair procedures for
CLUTCH INSTALLATION
1. Be sure the hardwood blocks (fig. 1) or
NOTE: The above step applies to all clutch
2. Place the driven disc against engine fly­
NOTE: If frame crossm em ber interferes with
3. If alignment marks were made on clutch
4. Install cover-to-flywheel bolts and washers.
NOTE: Tighten clutch cover-to-flywheel bolts
IMPORTANT: After installing clutch cover
5. Coat inside and outside grooves of clutch
Sec. 7E
Page 457
CLUTCHES
Check for