Chevrolet Light Duty Truck 1973 Service Manual page 325

Probable Cause
3. I n c o rr e c t parking brake adjustment on rea r brakes.
4. Metering valve i n s t a l l e d i n c o r r e c t l y .
5. Check valve i n s t a l l e d in o u t l e t to f r o n t disc brakes.
Probable Cause
1. A l l c o n d itio n s l i s t e d under "PULLS".
2. M alfu nctio n o f metering valve or p ro p o rtio n in g valve.
3. M alfu nctio n o f power brake u n i t .
4. Binding brake pedal mechanism.
5. Metering valve not hold in g o f f f r o n t brake a p p l ic a t io n .
REAR DRUM BRAKES SKIDDING PREMATURELY UNDER HARD BRAKE APPLICATION
Probable Cause
1. P rop o rtio n in g valve not c o n t r o l l i n g rea r l i n e pressure
to prevent rea r wheel lockup on hard brake a p p lic a t io n s
DIAGNOSIS—DISC BRAKES
DRAGGING BRAKES (CONT.)
3. Check and r e a d ju s t to c o r r e c t s p e c i f i c a t i o n s .
4. Port marked " i n l e t " goes to master c y l i n d e r , Port
marked " o u t l e t " goes to dis c c a l i p e r s .
5. Check o u t l e t hole and remove check va lve , i f l i n e is
connected to dis c brake c a l i p e r s .
G RABBING OR UNEVEN BRAKING A C TIO N
1. See "PULLS".
2. Replace and bleed system.
3. Check o p era tion and r e p a i r , i f necessary.
4. Check and lu b r i c a t e w ith Delco Brake Lube #5450032
(or e q u iv a le n t) i f necessary.
5. Replace metering valve and bleed system.
is not equipped w ith metering va lv e , check o th er
causes.
1. Replace p r o p o r tio n in g valve and bleed system.
v e h ic le is not equipped w ith p r o p o r tio n in g v a lv e ,
check o th e r causes l i s t e d under "PULLS" or "GRABBING
O R UNEVEN BRAKING ACTION".
BRAKES
Remedy
Rem edy
I f v e h ic le
Remedy
I f
LIGHT DUTY TRUCK SERVICE MANUAL
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