Chevrolet LIGHT DUTY TRUCK (SERIES 10-35) Service Manual page 399

5-8 BRAKES
C O N D IT IO N
Dragging Brakes
(A very light d rag is
present in all disc
brakes im m ediately a fte r
p ed al is released .) — Continued
G rab b in g or Uneven
Braking Action
Pulsation (roughness)
Felt during normal
brake a p p lica tio n .
LIG H T T R U CK SER V IC E M ANUAL
POSSIBLE CAUSE
3. Incorrect parking brake
adjustment on rear brakes.
4. Check valve installed in
outlet to front disc
brakes.
5. Incorrect installation of inboard
shoe and lining.
1. All conditions listed
under "PULLS".
2. Malfunction of combination
valve.
3. Malfunction of power
brake unit.
4. Binding brake ped al
mechanism.
1. Uneven pad w ear caused
by calip er not sliding
due to improper clear­
ance or dirt.
2. Uneven rotor w ear
causing a thickness
variation between the
two braking surfaces.
; / . . . . . -.;
;
CORRECTION
3. Check and readjust to
correct specifications.
4. Check master cylinder outlet
and remove check valve-if
present.
5. Refer to c a lip er installation in
this section.
1. All corrections listed
under "PULLS".
2. Replace and bleed system.
3. Check operation and
re p a ir, if necessary.
4. Check and lubricate, if
necessary. Possibly replace
ped al bushing an d /o r
spacer.
1. Remove calip er and correct
as necessary.
2. Machine rotors as follows:
a . Machine rotors to obtain a
circumferential thickness variation no
g rea ter than .0 0 0 5 " in 360° and a
lateral runout no g rea ter than .004"
(max. rate of change not exceed .001"
in 30°).
b. Check c a lip er freeness. W ith rotor
removed, install ca lip er and mounting
bolts (pins). Check fo r
* clearance a t both top and bottom of
calip er. If less than .005" is found, file
with a fla t file until a t least .0 0 5 " is
o btained. DO NO T EXCEED A
M AXIM UM of .01 2" per end or .024"
total clearance. C a lip e r clearance to
inboard and outboard reaction pads
must be equal within .00 4" both at the
top and bottom of the calip er. This is to
ensure correct alignm ent of ca lip er to
knuckle during a brake ap p licatio n .
c. Remove calip er a fte r freeness check.
Clean pins and sleeves, replace "O "
rings, and a p p ly a light coating of
silicone grease or equivalent to all
contact points and "O " rings.
.0 0 5 "-.0 1 2 "