Chrysler Vehicle User Manual page 228

TJ
BRAKE PADS/SHOES (Continued)
Fig. 31 Shoe Contact Surfaces
1 - ANCHOR PIN
2 - SUPPORT PLATE
3 - SHOE CONTACT SURFACES
(13) Lubricate and assemble adjuster screw.
(14) Install adjuster screw, spring and lever and
connect to adjuster cable.
(15) Adjust shoes to drum. (Refer to 5 - BRAKES/
HYDRAULIC/MECHANICAL/DRUM
MENTS).
(16) Install wheel/tire assemblies and lower vehi-
cle. (Refer to 22 - TIRES/WHEELS/WHEELS -
STANDARD PROCEDURE).
(17) Verify firm brake pedal before moving vehicle.
INSTALLATION - REAR DISC BRAKE PADS
(1) Bottom pistons in caliper bore with C-clamp.
Place an old brake shoe between a C-clamp and cal-
iper piston.
(2) Clean caliper mounting adapter and anti-rattle
springs.
(3) Lubricate anti-rattle springs with Mopar brake
grease.
(4) Install anti-rattle springs.
NOTE: Anti-rattle springs are not interchangeable.
(5) Install inboard brake pad in adapter.
(6) Install outboard brake pad in adapter.
(7) Tilt the top of the caliper over rotor and under
adapter. Then push the bottom of the caliper down
onto the adapter.
(8) Install caliper, (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/DISC BRAKE CALIPERS
- INSTALLATION).
(9) Install wheel and tire assemblies and lower
vehicle, (Refer to 22 - TIRES/WHEELS/WHEELS -
STANDARD PROCEDURE).
(10) Apply brakes several times to seat caliper pis-
tons and brake shoes and obtain firm pedal.
(11) Top off master cylinder fluid level.
DRUM
DESCRIPTION
The brake systems use a leading shoe (primary)
and trailing shoe (secondary). The mounting hard-
ware is similar but not interchangeable (Fig. 30).
OPERATION
When the brake pedal is depressed hydraulic pres-
sure pushes the rear brake wheel cylinder pistons
outward. The wheel cylinder push rods then push the
brake shoes outward against the brake drum. When
the brake pedal is released return springs attached
to the brake shoes pull the shoes back to there orig-
inal position. (Fig. 30)
DIAGNOSIS AND TESTING - BRAKE DRUM
RUNOUT
The maximum allowable diameter of the drum
braking surface is indicated on the drum outer edge.
Generally, a drum can be machined to a maximum of
1.52 mm (0.060 in.) oversize. Always replace the
drum if machining would cause drum diameter to
- ADJUST- exceed the size limit indicated on the drum.
BRAKE DRUM RUNOUT
Measure drum diameter and runout with an accu-
rate gauge. The most accurate method of measure-
ment involves mounting the drum in a brake lathe
and checking variation and runout with a dial indi-
cator.
Variations in drum diameter should not exceed
0.069 mm (0.0028 in.). Drum runout should not
exceed 0.18 mm (0.007 in.) out of round. Machine the
drum if runout or variation exceed these values.
Replace the drum if machining causes the drum to
exceed the maximum allowable diameter.
STANDARD PROCEDURE - BRAKE DRUM
MACHINING
The brake drums can be machined on a drum lathe
when necessary. Initial machining cuts should be lim-
ited to 0.12 - 0.20 mm (0.005 - 0.008 in.) at a time as
heavier feed rates can produce taper and surface
variation. Final finish cuts of 0.025 to 0.038 mm
(0.001 to 0.0015 in.) are recommended and will gen-
erally provide the best surface finish.
Be sure the drum is securely mounted in the lathe
before machining operations. A damper strap should
always be used around the drum to reduce vibration
and avoid chatter marks.
The maximum allowable diameter of the drum
braking surface is stamped or cast into the drum
outer edge.
BRAKES - BASE 5 - 19