Chevrolet 1977 light duty truck, Руководство по обслуживанию

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Fig. 5-38--Bendix Brake Caliper Assem bly
CALIPER H O U S IN G
Fig. 5-39-R em oving
the
Caliper Piston
2. D ra in the brake fluid fro m the caliper.
WARNING: Do not place t h e fingers in front
of t h e piston in a n a tte m p t to catch or
p ro te c t it w hen applying co m p re sse d air.
3. Using clean shop cloths, pad the interior o f the
caliper and remove the piston by directing compressed
air into the caliper inlet hole (fig. 5-39).
CAUTION: Use ju s t ju s t enough air pressure to
ease the piston out o f the bore. Do not blow
piston out o f the bore. I f the piston is seized or
cocked or does not come out readily, release the
air pressure a n d use a soft (brass) ham m er to
rap sharply on a n d around the end o f the
piston. R eapply air pressure to remove the
piston.
NOTE: An alternate m ethod o f rem oving the
piston is to stroke the brake pedal (gently) while
the hydraulic lines are still connected. This will
push the piston out o f the caliper bore.
4. Remove the boot from the piston bore.
5. Using a small piece o f wood or plastic, remove
the square ring seal from the piston bore.
CAUTION: Do not use a m etal tool o f any kind
f o r this operation as it m ay dam age the bore.
6. Remove the bleeder valve from the caliper.
Cleaning an d Inspection
CAUTION: The dust boot a n d piston seal are to
be replaced whenever the caliper is overhauled.
D iscard these parts.
1. Clean all parts (other than those m entioned
above in clean brake fluid. Use dry, filtered, compressor
air to blow out all passages in the caliper and bleeder
valve.
CAUTION: The use o f lubricated shop air will
leave a film o f m ineral oil on the m etal parts.
This m ay dam age rubber parts when they come
in contact after reassembly.
2. Check the sliding surfaces o f the caliper,
steering knuckle and support spring for rust or corrosion.
Clean up any surface defects with crocus cloth.
3. Carefully exam ine the outside surface o f the
piston for scoring, nicks, corrosion and worn or d am aged
plating. If any surface defects are detected, replace the
piston.
CAUTION: The piston outside diam eter is the
prim ary sealing surface in the caliper assembly.
It is m a nufactured a n d p la te d to close
tolerances. R efinishing by any m eans or the use
o f any abrasive is not acceptable practice.
4. Check the bore in the caliper for the same
defects as the piston. The piston bore, however, is not
plated and stains or m inor corrosion can be polished
with crocus cloth.
CAUTION: Do not use emery cloth or any other
fo r m o f abrasive. Thoroughly clean the caliper
after the use o f crocus cloth. I f the bore cannot
be cleaned up in this m anner, replace the
caliper.
Assembly
1. Lubricate the caliper piston bore and the N E W
piston seal with the clean brake fluid. Position the square
ring seal in the caliper bore groove.
2. Lubricate both sealing lips o f the dust boot and
the piston with a light film o f clean brake fluid. Place the
new boot over Piston Installer Tool J-24548. This is most
easily accomplished by placing the boot large diam eter
over the tool first, then riding the sm aller diam eter onto
the tool. The large d ia m e te r lip must then be slid off" the
tool to make ready for installation into the bore groove.
Install the boot (large bead) into the piston bore groove
by reaching inside o f Tool J-24548 and pressing the boot
bead into the groove (fig. 5-40).