(12) Inspect caliper piston for pitting, scratches, or
any physical damage. Replace piston if there is evi-
dence of scratches, pitting or physical damage.
CALIPER ASSEMBLY
CAUTION: Excessive vise pressure will cause bore
distortion and binding of piston.
(1) Clamp caliper in a vise (with protective caps
installed on jaws of vise).
(2) Dip new piston seal in clean brake fluid and
install in the groove of the caliper bore. Seal should
be positioned at one area in groove and gently
worked around the groove (Fig. 190), using only your
fingers until properly seated.NEVER USE AN OLD
PISTON SEAL.Be sure that fingers are clean and
seal is not twisted or rolled (Fig. 190).
(3) Coat new piston boot with clean brake fluid
leaving a generous amount inside boot.
(4) Position dust boot over piston after coating
with brake fluid.
CAUTION: Force must be applied to the piston uni-
formly to avoid cocking and binding of the piston in
the bore of the caliper.
(5) Install piston into caliper bore pushing it past
the piston seal until it bottoms in the caliper bore
(Fig. 191).
(6) Position dust boot into the counterbore of the
caliper assembly piston bore.
(7) Using a hammer and Installer Piston Caliper
Boot, Special Tool C-4689 and Handle, Special ToolC-4171, drive boot into counterbore of the caliper
(Fig. 192).
(8) Install guide pin sleeves and bushings. See
Install Guide Pin Bushings section in the caliper dis-
assembly section of this manual.
(9) Install brake pads. See Installing Brake Pads
in the Brake Pad Service Procedures section of this
manual.
(10) Before installing caliper assembly on vehicle,
inspect brake rotor. If any conditions as described in
Checking Brake Rotor for Runout and Thickness are
present the rotor, must be replaced or refaced. If the
rotor does not require any servicing, install caliper
assembly.
(11) Install brake hose onto caliper using banjo
bolt. Torque the brake hose to caliper assembly banjo
bolt to 33 N´m (24 ft. lbs.).New seal washers
Fig. 189 Honing Brake Caliper Piston Bore
Fig. 190 Installing New Piston Seal In Caliper
Fig. 191 Installing Piston Into Caliper Bore
NSBRAKES 5 - 75
DISASSEMBLY AND ASSEMBLY (Continued)
(4) Remove rotor from hub/bearing.
NOTE: When measuring the brake drum diameter,
the diameter should be measured in the center of
the area in which the park brake shoes contact the
surface of the brake drum.
(5) Using Gauge, Brake Shoe, Special Tool C-3919
or an equivalent,accuratelymeasure the inside
diameter of the park brake drum portion of the rotor
(Fig. 199).
(6) Using a ruler that reads in 64th of an inch,
accurately read the measurement of the inside diam-
eter of the park brake drum from the special tool
(Fig. 200).
(7) Reduce the inside diameter measurement of
the brake drum that was taken using Special Tool
C-3919 by 1/64 of an inch. Reset Gauge, Brake Shoe,
Special Tool C-3919 or the equivalent used, so that
the outside measurement jaws are set to the reduced
measurement (Fig. 201).(8) Place Gauge, Brake Shoe, Special Tool C-3919
or equivalent over the park brake shoes (Fig. 202).
The special tool must be located straight across at
the center (widest point) of the park brake shoes
(Fig. 202).
(9) Using the star wheel adjuster, adjust the park
brake shoes until the lining on the park brake shoes
just touches the jaws on the special tool.
(10) Install rotor on hub/bearing.
(11) Rotate rotor to verify that the park brake
shoes are not dragging on the brake drum. If park
brake shoes are dragging, remove rotor and back off
star wheel adjuster one notch and recheck for brake
shoe drag against drum. Continue with the previous
step until brake shoes are not dragging on brake
drum.
(12) Install disc brake caliper on caliper adapter
(Fig. 198). If required, refer to Rear Disc Brake Cal-
iper in the Removal And Installation Section in this
Fig. 199 Measuring Park Brake Drum Diameter
Fig. 200 Reading Park Brake Drum Diameter
Fig. 201 Setting Gauge To Park Brake Shoe
Measurement
Fig. 202 Adjusting Park Brake Shoes
5 - 80 BRAKESNS
ADJUSTMENTS (Continued)
