Disc Brakes - Jeep J-10 Series 1982 Technical & Service Manual

26-36 BRAKES
(4) Clean drums using soap and water solution. If
drums are grease or oil contaminated, clean drums with
alcohol before cleaning with soap and water.
(5) Inspect drums for cracks, severe scoring, dis
tortion, or hard spots (a series of shiny or dark colored
spots on contact surface). Replace drums that exhibit
these conditons. If drums appear in good condition, pro
ceed to next step.
(6) Refer to Specifications and measure drum inside
diameter. If diameter is within limits and refinishing
would not create an oversize condition, proceed to next
step. If diameter exceeds limits or if drum needs re
finishing but would exceed allowable size limits after
machining, replace drum.
(7) Mount drum in lathe according to lathe manu
facturer's instructions.
(8) Mount dial indicator on lathe so indicator stylus
contacts lining surface of drum; zero dial indicator.
(9) Measure drum radial runout.
(a) Rotate drum 360 degrees and observe
readings.
(b) Move indicator stylus until readings have
been taken across entire contact surface of drum.
(c) Drum runout must not exceed 0.005 inch
(0.12 mm) total indicator reading at any point. Also note
if indicator readings increase or decrease greatly as
stylus is moved across drum surface. Large changes
may indicate tapered or bell-mouthed drum.
(10) If drum is within limits and does not need re
finishing, install drum. If drum is notwithin limits or is
lightly scored, refinsh drum. Refer to Brakedrum
Refinishing.
Brakedrum Refinishing
(1) Sharpen or replace cutting tool bit if necessary.
(2) Install anti-chatter band on drum.
(3) Machine drum according to lathe manufacturer
recommendations for feed and speed. Do not remove
more than 0.010 inch-(0.25 mm) of stock during any cut.
(4) Check drum radial runout again after com
pleting machining operations.
NOTE: When brakeshoes are replaced on one wheel,
they must also be replaced on the opposite wheel to
ensure balanced braking.
SPECIFICATIONS
General Specifications
Brake Drum Radial Runout Limit 0.005 inches (0.12 mm)
Brake Drum Internal Diameter Umit:
CJ-Scrambler Models 10.060 inches (25.5 cm)
Cherokee-Wagoneer-J-10 Truck 11.060inches (28.09 cm)
J-20 Truck 12.060 inches (30.6 cm)
Brake Lining Wear Limits:
Riveted Lining Replacewhen worn to within
1/32 inch (0.79 mm) of rivet heads.
Bonded Lining Replacewhen worn to thickness of
approximately 1/16 inch (1.58 mm) or less.
80393
DISC BRAKES
Brakeshoe Replacement—Cherokeo-Wagonear-Truck Models 26*39
Brakeshoe Replacement—CJ-Scrambler Models 26-43
Caliper Overhaul—Cherokee-Wagoneer-Truck Models 26-41
Caliper Overhaul—CJ-Scrambler Models 26-45
GENERAL
Jeep vehicles are equipped with single piston, low-
drag, floating caliper front disc brakes. On CJ and
Scrambler models, the caliper is positioned over the
rotor and slides on two mounting pins which maintain
caliper position relative to the rotor and caliper anchor
plate (fig. 2G-30). On Cherokee, Wagoneer, and Truck
models, the caliper is positioned on mounting bolts lo
cated in the caliper support bracket (fig. 2G-31). Al
though the two caliper designs differ in construction,
caliper operation and service procedures are similar.
All models are equipped with an integral-type hub
and rotor. CJ and Scrambler models use an 11.7 inch
(29.71 cm) rotor. Cherokee, Wagoneer and J-10 Truck
models use a 12.0 inch (30.48 cm) rotor. J-20 Truck
models use a 12.5 inch (31.75 cm) rotor.
General
Disc Brake Operation
RotorService
Specifications
Page
26-36
26-37
26-47
26-50
Both caliper types consist of a one-piece casting con
taining a piston, piston bore, bleeder screw and fluid
inlet ports. The piston and piston seal are contained
within the piston bore. The piston seal is located in a
groove machined in the bore wall. A rubber dust boot
with integral metal retainer is used on all models. The
dust boot is located in a counterbore machined in the
upper edge of the piston bore and in a groove machined
in the exterior surface of the piston.
Caliper pistons are precision ground and plated to
provide a hard, durable surface. Lining wear is com
pensated for by the lateral sliding movement of the
caliper and by increased piston extension (fig. 2G-32).
A brakelining wear sensor, which consists of a strip of
flanged metal, is attached to the inboard brakeshoe on
Cherokee, Wagoneer and Truck models (a sensor is not