GMC 1986 P-Truck Service Manual page 449

3. Loosen the equalizer nut.
Adjust
• Equalizer nut until a light drag is felt
while rotating the wheels forward.
• Knob on the parking brake lever until a
definite snap over center is felt.
4. Release the parking brake and rotate the rear
wheels.
• There should be no brake drag.
5. Remove the safety stands and lower the vehicle.
• Unblock the front wheels.
INTERNAL EXPANDING (PROPELLER SHAFT)
CAUTION: See " Caution" on page 5-1 of this
section.
Block the front wheels.
1.
• Raise and support the rear axle with
suitable safety stands.
2. Remove the clevis pin connecting the pull rod
and relay lever.
3. Rotate the brake drum to align the access hole
with the adjusting screw.
• M anual tra n s m is s io n s - the adjusting
screw is located at the bottom of the shoe.
• A utom atic transm ission - the adjusting
screw is located at the top of the shoe.
• When adjusting the parking brake for the
first time, it will be necessary to remove the
lanced area from the drum. The drum must
be removed to clean out all the metal
shavings. Refer to PROPELLER SHAFTS
(Sec. 4A).
Adjust
• Adjusting screw until the drum cannot be
rotated by hand.
• Back off the adjusting screw ten notches.
The drum should rotate freely.
4. Place parking brake lever in the full release
position.
5. Take up the slack in the cable to overcome the
spring tension.
Adjust
• The clevis of the pull rod to align with the
hole in the relay lever.
6. Install the clevis pin.
• Install new cover in the drum access hold.
7. Remove the safety stands and lower the vehicle.
• Unblock the front wheels.
BRAKES 5-29