Chevrolet Light Duty Truck 1973, Service Manual

Page: 322 / 979

5 - 5 6 BRAKES
DIAGNOSIS—DRUM BRAKES
BRAKES CHATTER
Probable Cause
Rem edy
1. I n c o r r e c t l i n i n g to drum c le arance.
1,. Readjust to recommended cle ara nces.
2. Loose fla n g e p l a t e . 2,. T ighten s e c u re ly .
3. Grease, f l u i d , road du s t on l i n i n g .
3.. Clean o u t d u s t; re p la ce grease and f l u i d soaked l i n i n g s .
4. Weak o r broken r e t r a c t o r s p r in g .
4,. Replace.
5. Loose wheel be arings.
5,. Readjust.
6. Drums o u t - o f - r o u n d .
6,. Grind o r t u r n drums in p a ir s .
7. Cocked or d i s t o r t e d shoes.
7,. S t r a ig h te n o r r e p la c e .
8. Tapered o r ba rrel-shaped drums.
8,. Grind or t u r n i n p a i r s .
SHOE CLICK
Probable Cause Rem edy
1. Shoes l i f t o f f fla n g e p l a t e and snap back.
1. Change drums sid e to sid e or g rin d drums ( i n p a i r s ) .
2. Hold down spri ngs weak.
2., Replace s p rin g s .
3. Shoe bent.
3., S t ra ig h t e n .
4. Grooves i n fla n g e p l a t e pads.
4. Grind - lu b r i c a t e w ith Delco Brake Lube #5450032 (or
e q u i v a l e n t ) .
SNA P P IN G NOISE IN FRONT END
Probable Cause
Rem edy
1. Grooved fla n g e p l a t e pads. 1 . Grind pads o r re p la ce fla n g e p l a t e .
2. Lack o f l u b r i c a t i o n on moving p a r ts . 2.. L u b r ic a te a l l rubbing p o in ts w i t h Delco Brake Lube
#5450032 (or e q u i v a le n t ) .
3. Loose drums or fla n g e p l a t e s .
3.. T ig h te n.
4. Loose o r worn f r o n t end p a r ts . 4., Tighte n o r rep la c e d e f e c t iv e p a r t s .
T H U M P IN G NOISE W H E N BRAKES ARE APPLIED
Probable Cause Remedy
1. Too much clearance between shoes and anchors.
1
.
A d ju s t.
2. R e tra c to r springs unequal - weak.
2. Replace s p rin g s .
LIGHT DUTY TRUCK SERVICE MANUAL