Chevrolet Light Duty Truck 1973, Service Manual

Page: 321 / 979

BRAKES 5 -5 5
DIAGNOSIS—DRUM BRAKES
ONE WHEEL LOCKS
Probable Cause Rem edy
1. Gummy 1in in g .
2. T ir e tread s l i c k .
1. Replace the l i n i n g s .
2. Match up t i r e treads from sid e to sid e.
WET WEATHER: BRAKES GRAB OR W O N T HOLD
Probable Cause Rem edy
1. Lin in g s too s e n s i t i v e to water.
2. D i r t y brakes.
3. Bent fla n g e p la te - opening.
4. Scored drums.
1. Replace the 1in in g s .
2. Clean.
3. S t r a ig h t e n .
4. Grind o r tu r n in p a ir s ,
BRAKES SQUEAK
Probable Cause Rem edy
1. Flange p la te bent or shoes t w is t e d . 1.
2. M e t a l l i c p a r t i c l e s o r du st imbedded in l i n i n g . 2.
3. L in in g r i v e t s loose or l i n i n g not held t i g h t l y 3.
a g a in s t the shoe a t the ends.
4. Drums not square or d i s t o r t e d .
5. Shoes scraping on fla n g e p l a t e ledges.
5
.
6. Weak or broken hold down s p rin g s .
7. Loose wheel be arin gs.
8. Loose f la n g e p l a t e , anchor, drum wheel c y l i n d e r .
g
9. Loose shoe 1 i n k s .
9
10. Linin gs located wrong on shoes.
11. Brake drum s i l e n c e r s pring missing or too weak.
11.
S tr a ig h te n or repla ce damaged p a r ts .
Sand the surface s o f the l i n i n g s and drums. Remove a l l
p a r t i c l e s o f metal t h a t may be found in the surf ace o f
the 1i ni ngs.
Replace r i v e t s an d/or t ig h t e n l i n i n g by r e - r i v e t i n g .
Turn or g r in d o r re pla ce drums.
Apply Delco Brake Lube #5450032 (or e q u iv a le n t ) to
ledges. Replace w i th new shoe and l i n i n g s , i f d i s t o r t e d .
Replace d e f e c t iv e p a r ts .
Tighten to proper s e t t i n g .
T ig hte n.
T ig hte n.
I n s t a l l l i n i n g s c o r r e c t l y .
I n s t a l l new s p rin g .
LIGHT DUTY TRUCK SERVICE MANUAL