GMC 1976 ZEO 6083 Maintenance Manual page 224

1 . Incorrect lining.
2 . Thin drum .
3 . Dragging brakes.
Improperly adjusted parking
brake cables or stuck cable.
Weak or broken brake shoe return
springs.
Brake shoe to drum clearance too
small.
Wheel cylinder piston cups
swollen or distorted or piston
stuck .
Obstruction in line .
*BRAKES FADE
Cause
"Fade is a temporary reduction of brake effectiveness resulting from heat .
ONE WHEEL DRAGS
Cause
Backing plate shoe pad grooved.
Incorrect brake shoe radius .
BRAKES DO NOT
AUTOMATICALLY ADJUST
Cause
Worn, bent or distorted adjuster
lever.
Improper secondary lining to
drum clearance.
Brake linings excessively worn .
1 . Replace with new lining .
2. Replace drums.
3. Adjust or correct cause.
Adjust parking brake cables and lubricate.
Replace defective brake shoe springs and lubricate
brake shoe ledges and shoe contact at anchor pin
with brake lubricant No . 1050110 or equivalent .
Readjust brakes .
Replace inoperative or damaged parts . Look for
evidence of dirt in hydraulic system which could
cause damage to the cylinders or cups . See first
item under ALL BRAKES DRAG .
Obstruction in line may be caused by foreign
material or flattened or kinked tube . If dirt is
found in line, remove obstruction and flush hy-
draulic system with fresh brake fluid. If tube is
flattened or kinked, replace damaged parts.
Grind or file pads smooth and lubricate with brake
lubricant No . 1050110 or equivalent .
Replace malfunctioning brake shoe .
Replace adjuster lever.
Adjust clearance.
Install new linings.
Remedy
Remedy
Remedy
BRAKES 5- 5