ASSEMBLY - CALIPER PISTON AND SEAL
NOTE: Never use an old piston seal.
(1) Dip the new piston seal in clean brake fluid
and install it in the groove of the caliper bore. The
seal should be started at one area of the groove and
gently worked around and into the groove (Fig.
39)using only your clean fingers to seat it.
(2) Coat the new piston boot with clean brake
fluid.
(3) Position the dust boot over the piston after
coating it with brake fluid.
CAUTION: Force applied to the piston to seat it in
the bore must be applied uniformly to avoid cock-
ing and binding of the piston.
(4) Install piston into caliper bore pushing it past
the piston seal until it bottoms in the caliper bore
(Fig. 40).
(5) Position the dust boot into the counterbore of
the caliper assembly piston bore.
(6) Using a hammer and Installer, Special Tool
C-4689 or C-4842 (depending on piston size), and
Handle, Special Tool C-4171, drive the boot into the
counterbore of the caliper as necessary (Fig. 41).
(7) Reinstall the caliper on the vehicle and bleed
the brakes as necessary. Refer to Installation in this
section.
INSTALLATION - REAR DISC BRAKE CALIPER
(1) Completely retract caliper piston back into pis-
ton bore of the caliper.(2) If removed, install the brake rotor on the hub,
making sure it is squarely seated on the face of the
hub.
Fig. 39 Installing New Piston Seal
1 - CALIPER
2 - PISTON SEAL
3 - SEAL GROOVE
Fig. 40 Installing Piston Into Caliper Bore
1 - BOOT
2 - PISTON
3 - CALIPER
Fig. 41 Installing Dust Boot
1 - HAMMER
2 - SPECIAL TOOL C-4171
3 - SPECIAL TOOL C-4689 or C-4842
4 - CALIPER
5 - 30 BRAKES - BASERS
DISC BRAKE CALIPER - REAR (Continued)
CAUTION: Use care when installing the caliper
assembly onto the adapter, so the caliper guide pin
bushings do not get damaged by the mounting
bosses.
(3) Carefully lower caliper and brake shoes over
rotor and onto the adapter using the reverse proce-
dure for removal (Fig. 37).
CAUTION: When installing guide pin bolts extreme
caution should be taken not to cross-thread the cal-
iper guide pin bolts.
(4) Install the caliper guide pin bolts. Tighten the
guide pin bolts to a torque of 35 N´m (26 ft. lbs.).
CAUTION: When connecting the brake hose to the
caliper, install new brake hose to caliper special
washers.
(5) Install the brake hose on the caliper. To do
this, first place one NEW special copper washer on
each side of the hose fitting, then slide the banjo bolt
through the fitting. Next, thread the banjo bolt into
the threaded port on the rear of the brake caliper.
Tighten the banjo bolt to a torque of 47 N´m (35 ft.
lbs.).
(6) Install the wheel and tire assembly.
(7) Tighten the wheel mounting stud nuts in
proper sequence until all nuts are torqued to half
specification. Then repeat the tightening sequence to
the full specified torque of 135 N´m (100 ft. lbs.).
(8) Lower the vehicle.
(9) Remove the brake pedal depressor (holding)
tool.
(10) Bleed the hydraulic brake circuit to the brake
caliper. (Refer to 5 - BRAKES - STANDARD PROCE-
DURE)
(11) Road test the vehicle and make several stops
to wear off any foreign material on the brakes and to
seat the brake shoe linings.
DISC BRAKE CALIPER
ADAPTER
REMOVAL - FRONT DISC BRAKE CALIPER
ADAPTER
(1) Raise vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE)
(2) Remove front wheel and tire assembly, disc
brake caliper and brake shoes. (Refer to 5 - BRAKES/
HYDRAULIC/MECHANICAL/BRAKE PADS/SHOES
- REMOVAL)
(3) Remove two bolts fastening adapter to steering
knuckle, then remove disc brake caliper adapter.
INSTALLATION - FRONT DISC BRAKE CALIPER
ADAPTER
(1) Place adapter over brake rotor and align
adapter mounting holes to knuckle.
CAUTION: Adapter mounting bolts have a special
DacrometTcoating applied to resist corrosion. If
mounting bolts need to be replaced, use only
MoparTreplacement parts.
(2) Install adapter mounting bolts and tighten to
169 N´m (125 ft. lbs.) torque.
(3) Install brake shoes, disc brake caliper and
wheel and tire assembly. (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/BRAKE PADS/SHOES -
INSTALLATION)
(4) Lower vehicle.
(5) Pump the brake pedal several times to set the
pads to the brake rotor.
(6) Check and adjust brake fluid level as neces-
sary.
DISC BRAKE CALIPER GUIDE
PINS
REMOVAL - DISC BRAKE CALIPER GUIDE PINS
(TRW BRAKES)
(1) Raise the vehicle. Refer to HOISTING in
LUBRICATION AND MAINTENANCE.
(2) Remove the front tire and wheel assembly.
(3) Remove the two brake caliper guide pin bolts
(Fig. 42).
Fig. 42 Brake Caliper Mounting
1 - BRAKE HOSE
2 - ADAPTER MOUNTING BOLTS
3 - BANJO BOLT
4 - CALIPER GUIDE PIN BOLTS
RSBRAKES - BASE5-31
DISC BRAKE CALIPER - REAR (Continued)
(4) Remove the disc brake caliper from the disc
brake caliper adapter and hang it out of the way
using wire or a bungee cord. Use care not to overex-
tend the brake hose when doing this.
(5) Remove the guide pins and boots from the
adapter as shown (Fig. 43).
INSTALLATION - DISC BRAKE CALIPER GUIDE
PINS (TRW BRAKES)
(1) Lubricate the guide pins and inside the boots
with the packet supplied with the service kit, Syth-
eso GLK-1 lubricant or equivalent.
(2) Install the guide pins and boots in the adapter
as shown (Fig. 43). The boots have grooves built into
their inner lips to fit onto the pins and adapter.
CAUTION: Use care when installing the caliper onto
the disc brake adapter to avoid damaging the boots
on the caliper guide pins.
(3) Install the disc brake caliper over the brake
shoes on the brake caliper adapter.
(4) Align the caliper guide pin bolt holes with the
guide pins. Install the caliper guide pin bolts and
tighten them to a torque of 35 N´m (26 ft. lbs.) (Fig.
42).
(5) Install the tire and wheel assembly. Tighten
the wheel mounting nuts to a torque of 135 N´m (100
ft. lbs.).
(6) Lower the vehicle.
(7) Pump the brake pedal several times before
moving the vehicle to set the shoes to the brake
rotor.
DRUM
REMOVAL
(1) Raise the vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE).
(2) Remove the tire and wheel assembly from the
vehicle
(3) Remove the rear brake shoe adjusting hole
cover plug.
(4) Insert a thin screwdriver into brake adjusting
hole and hold adjusting lever away from notches of
adjusting screw star wheel.
(5) Insert another thin screwdriver into brake
adjusting hole and engage notches of brake adjusting
screw star wheel. Release brake adjustment by pry-
ing upward with adjusting tool.
(6) Remove rear brake drum from rear hub/bear-
ing assembly.
NOTE: It may be necessary to insert M8 X 1.25 MM
bolts into the two removal holes on the drum to
force the drum off the hub.
INSTALLATION
(1) Adjust brake shoe assemblies so as not to inter-
fere with brake drum installation.
(2) Install the rear brake drums on the hubs.
(3) Adjust drum brake shoes as necessary per pro-
cedure found in the Adjustment section of this ser-
vice manual group (Refer to 5 - BRAKES/
HYDRAULIC/MECHANICAL/DRUM -
ADJUSTMENTS).
(4) Install wheel and tire assembly.
(5) Tighten the wheel mounting stud nuts in
proper sequence until all nuts are torqued to half
specification. Then repeat the tightening sequence to
the full specified torque of 135 N´m (100 ft. lbs.).
(6) Lower the vehicle.
Fig. 43 Guide Pins And Boots
1 - PINS
2 - BOOTS
5 - 32 BRAKES - BASERS
DISC BRAKE CALIPER GUIDE PINS (Continued)
PROPORTIONING VALVE SPECIFICATIONS
WHEEL
BASEDRIVE
TRAINSALES
CODEBRAKE
SYSTEMSPLIT
POINTSLOPEINLET
PRESSURE
PSIOUTLET
PRESSURE
PSI
SWB FWD BRB-BGF159DISC/
DRUM W/O
ANTILOCKVAR. 0.59 1000 PSI 675-875 PSI
REMOVAL - PROPORTIONING VALVE (HEIGHT
SENSING)
(1) Using a brake pedal depressor, move and lock
the brake pedal to a position past its first 1 inch of
travel. This will prevent brake fluid from draining
out of the master cylinder when the brake tubes are
removed from the proportioning valve.
(2) Raise vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE).
CAUTION: Before removing the brake tubes from
the proportioning valve, the proportioning valve and
the brake tubes must be thoroughly cleaned. This is
required to prevent contamination from entering the
proportioning valve or the brake tubes.
(3) Remove the four brake tubes from the inlet and
outlet ports of the proportioning valve (Fig. 81).
(4) Remove the two bolts attaching the proportion-
ing valve and bracket to the vehicle (Fig. 81).
(5) Slide the bracket out from under rear track bar
bracket. Lower the valve down enough to pull itsactuator rod out of the axle bracket and remove the
proportioning valve from the vehicle.INSTALLATION - PROPORTIONING VALVE
(HEIGHT SENSING)
(1) Install the end of the actuator rod through the
axle bracket grommet and slide the proportioning
valve bracket under the rear track bar body bracket
(Fig. 81).
(2) Install the proportioning valve attaching bolts
(Fig. 81). Tighten the attaching bolts to a torque of
54 N´m (40 ft. lbs.).
(3) Install the four chassis brake lines into the
inlet and outlet ports of the proportioning valve (Fig.
81). Tighten all tube nuts to a torque of 17 N´m (145
in. lbs.).
CAUTION: The height sensing proportioning valve
is not adjustable. No attempt should be made to
adjust it.
(4) Bleed the brake system thoroughly to ensure
that all air has been expelled from the hydraulic sys-
tem. (Refer to 5 - BRAKES - BASE - STANDARD
PROCEDURE).
(5) Lower the vehicle to the ground.
(6) Road test the vehicle to verify proper operation
of the brake system.
ROTOR
DIAGNOSIS AND TESTING - BRAKE ROTOR
Any servicing of the rotor requires extreme care to
maintain the rotor within service tolerances to
ensure proper brake action.
Excessive runout or wobble in a rotor can increase
pedal travel due to piston knock-back. This increases
guide pin sleeve wear due to the tendency of the cal-
iper to follow the rotor wobble.
When diagnosing a brake noise or pulsation, the
machined disc braking surface should be checked and
inspected.
Fig. 81 PROPORTIONING VALVE MOUNTING
1 - LEFT REAR OUTLET TUBE
2 - RIGHT REAR OUTLET TUBE
3 - RIGHT REAR INLET TUBE
4 - MOUNTING BOLTS
5 - LEFT REAR INLET TUBE
RSBRAKES - BASE5-55
PROPORTIONING VALVE (Continued)
BRAKING SURFACE INSPECTION
Light braking surface scoring and wear is accept-
able. If heavy scoring or warping is evident, the rotor
must be refaced or replaced. (Refer to 5 - BRAKES/
HYDRAULIC/MECHANICAL/ROTORS - STAN-
DARD PROCEDURE).
Excessive wear and scoring of the rotor can cause
improper lining contact on the rotor's braking sur-
face. If the ridges on the rotor are not removed before
new brake shoes are installed, improper wear of the
shoes will result.
If a vehicle has not been driven for a period of
time, the rotor's braking surface will rust in the
areas not covered by the brake shoes at that time.
Once the vehicle is driven, noise and chatter from
the disc brakes can result when the brakes are
applied.
Some discoloration or wear of the rotor surface is
normal and does not require resurfacing when lin-
ings are replaced. If cracks or burned spots are evi-
dent, the rotor must be replaced.
ROTOR MINIMUM THICKNESS
Measure rotor thickness at the center of the brake
shoe contact surface. Replace the rotor if it is worn
below minimum thickness or if machining the rotor
will cause its thickness to fall below specifications.
CAUTION: Do not machine the rotor if it will cause
the rotor to fall below minimum thickness.
Minimum thickness specifications are cast on the
rotor's unmachined surface (Fig. 82). Limits can also
be found in this section's specification table. (Refer to
5 - BRAKES/HYDRAULIC/MECHANICAL/ROTOR -
SPECIFICATIONS)
ROTOR THICKNESS VARIATION
Thickness variation in a rotor's braking surface
can result in pedal pulsation, chatter and surge. This
can be caused by excessive runout in the rotor or the
hub.
Rotor thickness variation measurements should be
made in conjunction with measuring runout. Mea-
sure thickness of the brake rotor at 12 equal points
around the rotor braking surface with a micrometer
at a radius approximately 25 mm (1 inch) from edge
of rotor (Fig. 83). If thickness measurements vary
beyond the specification listed in the specifaction
table (Refer to 5 - BRAKES/HYDRAULIC/MECHAN-
ICAL/ROTOR - SPECIFICATIONS), the rotor should
be refaced or replaced. (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/ROTORS - STANDARD
PROCEDURE).
Fig. 82 Minimum Brake Rotor Thickness Markings
(Typical)
1 - ROTOR MINIMUM THICKNESS MARKING
2 - ROTOR
Fig. 83 Checking Rotor For Thickness
1 - CALIPER
5 - 56 BRAKES - BASERS
ROTOR (Continued)
ROTOR RUNOUT
On-vehicle rotor runout is the combination of the
individual runout of the hub face and the runout of
the rotor. (The hub and rotor runouts are separable).
To measure rotor runout on the vehicle, first remove
the tire and wheel assembly. Reinstall the wheel
mounting nuts on the studs, tightening the rotor to
the hub. Mount the Dial Indicator, Special Tool
C-3339, with Mounting Adaptor, Special Tool SP-
1910 on steering arm. The dial indicator plunger
should contact braking surface of rotor approximately
ten millimeters from edge of rotor (Fig. 84). Check
lateral runout on both sides of the rotor, marking the
low and high spots on both. Runout limits can be
found in the specification table in this section. (Refer
to 5 - BRAKES/HYDRAULIC/MECHANICAL/RO-
TOR - SPECIFICATIONS)
If runout is in excess of the specification, check the
lateral runout of the hub face. Before removing the
rotor from the hub, place a chalk mark across both
the rotor and the one wheel stud closest to where the
high runout measurement was taken. This way, the
original mounting spot of the rotor on the hub is
indexed (Fig. 85).
Remove the rotor from the hub.
NOTE: Clean the hub face surface before checking
runout. This provides a clean surface to get an
accurate indicator reading.
Mount Dial Indicator, Special Tool C-3339, and
Mounting Adaptor, Special Tool SP-1910, to the steer-
ing knuckle. Position the indicator stem so it contacts
the hub face near the outer diameter. Care must be
taken to position stem outside of the stud circle, but
inside of the chamfer on the hub rim (Fig. 86).Hub runout should not exceed 0.03 mm (0.0012
inch). If runout exceeds this specification, the hub
must be replaced. (Refer to 2 - SUSPENSION/
FRONT/HUB / BEARING - REMOVAL)(Refer to 2 -
SUSPENSION/REAR/HUB / BEARING - REMOVAL)
Fig. 84 Checking Rotor Runout
1 - SPECIAL TOOL SP-1910
2 - 10 MILLIMETERS FROM EDGE
3 - DISC SURFACE
4 - SPECIAL TOOL C-3339
Fig. 85 Marking Rotor and Wheel Stud
1 - CHALK MARK
Fig. 86 Checking Hub Runout
1 - HUB SURFACE
2 - SPECIAL TOOL C-3339
3 - SPECIAL TOOL SP-1910
RSBRAKES - BASE5-57
ROTOR (Continued)
If the hub runout does not exceed this specifica-
tion, install the rotor back on the hub, aligning the
chalk marks on the rotor with a wheel mounting
stud, two studs apart from the original stud (Fig. 87).
Tighten nuts in the proper sequence and torque to
specifications.
Recheck brake rotor runout to see if the runout is
now within specifications. (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/ROTOR - SPECIFICA-
TIONS)
If runout is not within specifications, reface or
replace the brake rotor. (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/ROTORS - STANDARD
PROCEDURE)
STANDARD PROCEDURE - BRAKE ROTOR
MACHINING
NOTE: Refacing the rotor is not required each time
the brake pads are replaced, only when the need is
foreseen.
Any servicing of the rotor requires extreme care to
maintain the rotor within service tolerances to
ensure proper brake action.
If the rotor surface is deeply scored or warped, or
there is a complaint of brake roughness or brake
pedal pulsation, the rotor should be refaced using a
hub-mounted on-car brake lathe (Fig. 88), or
replaced.
The use of a hub-mounted on-car brake lathe is
highly recommended to eliminate the possibility of
excessive runout. It trues the brake rotor to the vehi-
cle's hub and bearing.NOTE: All rotors have markings for minimum allow-
able thickness cast on an un-machined surface of
the rotor (Fig. 89) (Fig. 90). Minimum thickness
specifications can also be found in the specification
table in this section. (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/ROTOR - SPECIFICATIONS)
Fig. 87 Index Rotor And Wheel Stud
1 - CHALK MARK
Fig. 88 On-Car Brake Lathe
1 - ON-CAR BRAKE LATHE
Fig. 89 Front Brake Rotor
1 - ROTOR MINIMUM THICKNESS MARKING
2 - ROTOR
Fig. 90 Rear Brake Rotor Minimum Thickness
Markings
1 - ROTOR MINIMUM THICKNESS AND DRUM MAXIMUM
DIAMETER SPECIFICATIONS ARE SHOWN ON THIS SURFACE
2 - REAR ROTOR
5 - 58 BRAKES - BASERS
ROTOR (Continued)
Minimum allowable thickness is the minimum
thickness which the brake rotor machined surface
may be cut to.
CAUTION: Do not machine the rotor if it will cause
the rotor to fall below minimum thickness.
Before installation, verify the brake rotor face and
the hub adapters are free of any chips, rust, or con-
tamination.
When mounting and using the brake lathe, strict
attention to the brake lathe manufacturer's operating
instructions is required.
Machine both sides of the brake rotor at the same
time. Cutting both sides at the same time minimizes
the possibility of a tapered or uneven cut.
When refacing a rotor, the required TIR (Total
Indicator Reading) and thickness variation limits
MUST BE MAINTAINED. Extreme care in the oper-
ation of rotor turning equipment is required. Specifi-
cations for brake rotor machining can be found in
this section's specification table. (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/ROTOR -
SPECIFICATIONS)
REMOVAL - FRONT BRAKE ROTOR
(1) Raise vehicle on jackstands or centered on a
frame contact type hoist. See Hoisting in Lubrication
and Maintenance.
(2) Remove the front wheel and tire assembly.
(3) Remove the two mounting bolts securing the
disc brake caliper adapter with brake caliper to the
steering knuckle (Fig. 91).
(4) Remove the disc brake caliper and adapter as
an assembly from the steering knuckle (Fig. 91).
Hang the assembly out of the way using wire or a
bungee cord. Use care not to overextend the brake
hose when doing this.
(5) Remove any retainer clips from the wheel
mounting studs.
(6) Remove brake rotor from hub by pulling it
straight off wheel mounting studs (Fig. 91).
INSTALLATION - FRONT BRAKE ROTOR
(1) Install the brake rotor back on the hub and
bearing (Fig. 91).(2) Install brake caliper and adapter back over
brake rotor aligning adapter with mounting holes on
steering knuckle (Fig. 91).
(3) Install the two adapter mounting bolts securing
the adapter to the steering knuckle. Tighten the
mounting bolts to 169 N´m (125 ft. lbs.) torque.
(4) Install wheel and tire assembly on vehicle.
Tighten the wheel mounting lug nuts in proper
sequence until all nuts are torqued to half specifica-
tion, then repeat the tightening sequence to the full
specified torque of 135 N´m (100 ft. lbs.).
(5) Lower vehicle to the ground.
Fig. 91 Front Brake Mounting
1 - BRAKE ROTOR
2 - HUB AND BEARING
3 - STEERING KNUCKLE
4 - ADAPTER MOUNTING BOLTS
5 - BRAKE CALIPER
6 - ADAPTER
7 - CLIP
RSBRAKES - BASE5-59
ROTOR (Continued)