GMC 4000 Series Service Manual page 263

Sec. 5C
Page 254B
PARKING BRAKES
4. Adjust lining to drum clearance as previ­
ously directed under "Brake Adjustment."
BRAKE DRUM REMOVAL
1. Remove brake shoes as previously directed
under "Brake Shoe Removal."
2. Disconnect propeller shaft at transmission.
Remove bolts attaching center bearing bracket to
crossm em ber, then lower center bearing and front
propeller shaft to floor.
3. Remove brake drum from bolts in trans­
mission mainshaft flange. Remove four nuts, lock
washers, and bolts attaching oil deflector to inner
side of brake drum.
BRAKE DRUM INSTALLATION
1. Position oil deflector in brake drum and
attach with four bolts, lock washers, and nuts.
Tighten nuts to 5-8 foot-pounds torque.
2. Install brake drum on bolts in transmission
mainshaft flange. Connect propeller shaft at trans­
m ission and attach center bearing bracket to frame
crossm em ber. Refer to "PROPELLER SHAFTS"
(SEC. 4D) of this manual for universal joint con­
struction.
3. Install brake shoes as previously directed
under "Brake Shoe Installation."
IMPORTANT
Any time that brake shoes have been removed
or disturbed for any service operation it is ad­
visable to adjust the brake as directed under "Brake
Adjustment."
Figure 3 illustrates the internal-expanding
type parking brake used on the PS-4500 Models.
In order to remove components of this brake, it is
necessary to disconnect the propeller shaft from
the transm ission at the front universal joint. This
can be done as instructed in "PROPELLER SHAFTS"
(SEC. 4D) in this Manual. Then remove four nuts
from transmission output flange and remove pro­
peller shaft yoke and brake drum from flange.
NOTE: It may be necessary to back off the
shoe adjustment before removing drum.
Brake components are now ejqposed.
REMOVAL
1. Remove two pull-back springs.
2. Remove guide plate from anchor pin.
3. Remove shoe holddown cups, springs, and
washers from hold-down pins. Remove pins from
G M C S E R V I C E M A N U A L
INTERNAL-EXPANDING TYPE BRAKE
1 Brake Cable
2 Adjustable Clevis
3 Connecting Lever
4 Return Spring
5 Link
Lock Nut
6
7 Operating Lever
Inner Shoe
8
Figure 2— Two Sh o e (D uo-G rip) Parking Brake
backing plate.
4. Pull brake shoe and lining assem blies away
from anchor pin and remove lever strut and strut
spring.
5. Lift brake shoe and lining assem blies with
adjusting nut and bolt and connecting spring off
backing plate.
. Move tops of shoes toward one another until
6
adjusting nut and bolt assembly and connecting
spring drop off.
7. Remove clip from pin and remove pin,
lever, and washer from primary shoe and lining
assembly (the primary shoe is the shoe with the
short lining).
. Compress spring on cable and remove cable
8
from lever.
9. If necessary to remove anchor pin, straight­
en bent over tangs of washer from pin hex and
9 Outer Shoe
10 Brake Drum
11 Adjusting Nut
12 Lock Nut
13 Adjusting Bolt
14 Return Spring
15 Adjuster Bracket
T P M - 9 8 2 9