Chevrolet 1977 light duty truck Service Manual page 387

C O N D IT IO N
Pulls
N o ise (h ig h p itched squ eak
w ith o u t b ra k e a p p lie d ) .
B rake roughness o r c h a tte r
(P e d a l Pulsates)
POSSIBLE CAUSE
1. Incorrect tire pressures.
2. Front e n d out o f lin e .
3. U n m atch ed tires on same
a x le .
For r a d ia l tire le a d
re fe r to Section 3E.
4 . Restricted b ra k e pipes
or hoses.
5. M a lfu n c tio n in g c a lip e r
assem bly.
6. D efective or d a m a g e d
shoe a n d lin in g (g rea s e
or b ra k e flu id on
lin in g or b en t shoe).
7. M a lfu n c tio n in g re a r
b rakes.
8. Loose suspension parts.
9. Loose c a lip e rs .
1. Front linin gs w orn out.
1. Excessive la te r a l runout.
2. P a ra lle lis m not w ithin
specifications.
3. W h e e l B earin gs not
a d ju s te d .
4 . R ear drums out o f ro und.
CO R R E C TIO N
1. In fla te evenly on both sides to
the recom m ended pressures.
2. C heck a n d a lig n to m an ufactu rer's
sp ecification s.
3 . Tires with a p p ro x im a te ly the
same am o un t of tre a d should
b e used on the same a x le .
4 . C heck fo r solf hoses and
d a m a g e d lines. R eplace w ith
new hoses a n d new d o u b le ­
w a lle d steel b ra k e tu b in g .
5 . Check fo r stuck or sluggish
pistons, p ro p e r lu b ric a tio n .
Remove a n d re b u ild c a lip e r.
6 . Install new shoe a n d linin g
in com plete a x le sets.
7 . Check fo r in o p e ra tiv e auto
a d ju s tin g m echanism , d efe c tiv e
lin in g (g rea s e or b ra k e
flu id on lin in g ) or
d efe c tiv e w h eel cylinders.
R e p a ir as necessary.
8. Check a n d to rq u e a ll
suspension mountings to
specifications.
9 . Check a n d to rq u e bolts to
sp ecification s.
1. R eplace linin gs.
1. Check p e r instructions a n d
re p la c e or m achine rotor,
if not w ith in specifications.
2 . Check p er instructions a n d
re p la c e or m ach ine the rotor,
if not w ith in specifications.
3 . A djust w h e e l b e a rin g s to
correct specifications.
4 . C heck runout a n d , if not
w ith in specification s, turn
the drums (no t over
maxim um o f 0 .0 6 0 on the
d ia m e te r).