Chevrolet Light Duty Truck 1973 Service Manual page 299

BRAKE FLUID
INLET HOLE
AIR HOSE
Fig. 61 -Removing Piston From Caliper
piston is to stroke the brake pedal (gently)
while the hydraulic lines are still connected.
This will push the piston out of the caliper
bore.
4. Using a screwdriver and caution so as not to scratch
the piston bore, pry the dust boot out of the caliper
piston bore.
5. Using a small piece of wood or plastic, remove the
piston seal from its groove in the caliper piston
bore.
Do not use a metal too l of any kind
CAUTIO N:
for t h i s operation as i t may damage the bo re .
. Remove the bleeder valve from the caliper.
6
7. Remove and discard the sleeves and bushings from
the caliper ears.
Cleaning and Inspection
The dust b o o t , piston s e a l , rubber
CAUTIO N:
bushings and sleeves are t o be replaced each
time that the caliper i s overhauled. Discard
-
these parts do not bother t o clean and inspect
them.
1. Clean all parts (other than those mentioned above)
in clean brake fluid. Use dry, filtered, compressed
air to blow out all passages in the caliper and
bleeder valve.
The use of lubricated shop air w i l l
CAUTIO N:
leave a film of mineral o i l on the metal parts.
This may damage rubber parts when they come
i n contact after reassembly.
2. Check the mounting bolts for corrosion or other
damage. Do not attempt to clean up the bolts. If
they appear corroded - replace them.
3. Carefully examine the outside surface of the piston
for scoring, nicks, corrosion and worn or damaged
chrome plating. If any surface defects are detected,
replace the piston.
The piston outside diameter i s the
CAUTION:
primary sealing surface i n the caliper assembly.
I t i s manufactured and plated t o close
t olerances. Refinishing by any means or the use
of any abrasive i s not an 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 minor corrosion can be
polished with crocus cloth.
CAUTIO N:
SHOP
TOWELS
form of abrasive. Thoroughly clean the caliper
after the use of crocus c l o t h . If the bore cannot
be cleaned up i n t h i s manner, replace the
c a l i p e r .
Assembly
1. Lubricate the caliper piston bore and the new
piston seal with clean brake fluid. Position the seal
in the caliper bore groove.
2. Lubricate the piston with clean brake fluid and
assemble a new boot into the groove in the piston
so that the fold faces the open end of the piston as
shown in Figure 62.
3. Insert the piston into the caliper bore using care not
to unseat the seal and force (50 to 100 pounds force
required) the piston to the bottom of the bore.
4. Position the dust boot in the caliper counterbore
and seat using Boot Installer Tool J-22904 as shown
in Figure 63.
CAUTIO N:
sure that the retaining ring moulded into the
boot i s not bent and that the boot i s installed
below the caliper face and evenly a l l around.
5. Install the bleeder screw and torque to
specifications.
Do not use emery cloth or any other
Check the boot instal la ti o n t o make
DU ST B O O T
PISTON
END OF GROOVE
Fig. 6 2 -Installing Boot to Piston
LIGHT DUTY TRUCK SERVICE MANUAL
BRAKES 5 -3 3