brake light DODGE TRUCK 1993 Service Owner's Manual

BRAKES
i - 9

Fig.
4 Metering
Valve
Hold
Off Tool (4) If pressure bleeding equipment will be used, hold
metering valve open with tool C-4121. Tool is installed on valve stem to hold it (and valve) open (Fig. 4).

CAUTION:
Under
no
condition should
a
rigid clamp,

wedge
or
block
be
used
to
press
the
valve stem
in­

ward
to
hold
the
valve open. This
practice
could dam­
age
the
valve resulting
in
valve
failure and
loss
of
front
brake action. Note
that the
valve stem
is in its in­
nermost position when
there
is no
pressure present.

No
attempt
should
be
made
to further
depress
the

valve stem.

(5) Bleed system in following sequence and bleed
only one wheel or valve at a time:
• master cylinder • RWAL hydraulic valve
• right rear wheel
• left rear wheel
• right front wheel • left front wheel (6) Bleed master cylinder first. If replacement cylin­
der will be installed, bleed cylinder on bench before in­ stalling it.
(7) If manual bleeding: (a) Fill master cylinder with fresh fluid and open
all bleed screws. Close bleed screws when fluid be­
gins to trickle from each bleed screw opening. (b) Top off master cylinder with fresh fluid.
(c) Clean bleed screw on RWAL valve. Then in­
stall bleed hose on bleed screw. Insert end of hose
in clear container partially filled with brake fluid.
Be sure hose end is immersed in brake fluid or air
will be drawn back into valve.
(d) Have helper press and hold brake pedal to
floorpan. Then tighten bleed screw at this point and have helper release pedal.
(e) Open bleed screw and have helper press pedal
down again. Continue bleeding until only clear,
bubble free fluid flows into glass container. (f) Continue bleeding operations at remaining
wheel brake units.
(8) If pressure bleeding: (a) Clean bleed screw on RWAL valve. Then in­
stall bleed hose on bleed screw. Insert end of hose in clear container partially filled with brake fluid.
Be sure hose end is immersed in brake fluid or air
will be drawn back into valve.
(b) Open bleed screw at RWAL valve and allow
fluid to flow through valve.
(c) Stop bleeding when only clear, bubble free
fluid flows into fluid container.
(d) Continue bleeding operations in recom­
mended sequence at wheel brake units. Start with
left rear wheel.
(9) Repeat bleeding procedure if system indicator
lights remain on or if pedal still feels spongy.

WHEEL
NUT
TIGHTENING
The wheel attaching nuts must be tightened properly
to ensure efficient brake operation. Overtightening the nuts or tightening them in the wrong sequence could
cause distortion of the brake rotors and drums.
Impact wrenches are not the best tools for tighten­
ing wheel nuts. A torque wrench should be used for
this purpose at all times.
The correct tightening sequence is important in
avoiding rotor and drum distortion. The correct se­
quence is in a diagonal crossing pattern (Fig. 5). Seat the wheel and install the wheel nuts finger
tight. Tighten the nuts in the sequence to 1/2 re­ quired torque. Then repeat the tightening sequence
to final specified torque.

STOP
LIGHT SWITCH ADJUSTMENT
The plunger-type stop light switch is attached to
the brake pedal bracket. The switch is directly actu­ ated by a tang on the brake pedal. Switch adjust­
ment is as follows: (1) Push switch through clip in mounting bracket
until switch is sealed against bracket. Brake pedal
will move forward slightly.
(2) Gently pull back on brake pedal as far as it will

go.
(3) Switch will ratchet rearward to correct posi­
tion. Further adjustment is not required.

i - 12
BRAKES

•
Fig.
6 integral Cylinder
Components

Cylinder Cleaning And Inspection Clean the cylinder body and cover with brake fluid
or brake cleaner only. Do not use any other type of solvents, or cleaning agent. Inspect the cylinder body and bore. Light discolor­
ation of the cylinder bore is normal and is an accept­
able condition. The bore should be smooth and free of
scores, scratches, corrosion and rust. Replace the cyl­
inder if the bore is worn, scored, or corroded.
Do not hone the bore in an attempt to restore the
surface finish. Replace the cylinder if the bore is
damaged in any way. Also replace the cylinder if the
body is cracked, porous, or the compensator port at
the bottom of each reservoir is blocked or damaged.
Inspect the cover and gasket. Replace the gasket if
distorted, cut, or torn. Replace the cover and retain­
ing wire if either component is distorted or damaged
in any way.
Do not reuse the old piston assemblies. Discard
these parts as soon as they are removed. Install re­
placement primary and secondary piston assemblies
only.

INTEGRAL
CYLINDER ASSEMBLY
(1) Coat cylinder bore and replacement piston as­
semblies with liberal quantity of clean brake fluid.
(2) Install secondary piston assembly in bore with
a turning motion. Do not use metal tools of any kind
to help ease piston into bore. Sharp edge tools will
scratch bore and cut piston seals.
(3) If cylinder is equipped with stop screw for sec­
ondary piston, press piston to bottom of bore and in­
stall screw.
(4) Install primary piston in bore.
(5) Press pistons inward with wood dowel and in­
stall piston snap ring. Be sure snap ring is fully
seated.
(6) Install new gasket on cover if necessary.
(7) Install cover retaining wire on cylinder if re­
moved. (8) Fill and bleed master cylinder on bench before
installing it in vehicle. Refer to following procedure.
BLEEDING
NEW
OR
OVERHAULED MASTER

CYLINDER
A new or overhauled master cylinder should be
purged of all air before installation on the vehicle. Cylinder bleeding is performed on the bench. Bleeding tools for the integral master cylinder in­
clude fabricated bleed tubes and a wood dowel.
Bleeding tools for the two-section master cylinder in­ clude bleed tubes C-4029 and a wood dowel (Fig. 7).

CYLINDER BLEEDING PROCEDURE
(1) Mount master cylinder assembly in vise.
(2) Attach bleed tubes to cylinder outlet ports and
insert tubes in reservoir fluid compartments (Fig. 7).
Bleed tubes can be fabricated from steel or copper
tubing and appropriate size fittings.
(3) Fill reservoir with fresh brake fluid. (4) Press cylinder pistons inward with wood dowel.
Then release pistons and allow them to return under spring pressure.
(5) Continue bleeding operations until air bubbles
are no longer visible in fluid.

Fig.
7 Master Cylinder
Bleeding—
Two-Section
Cylinder
Shown

MASTER
CYLINDER INSTALLATION
(1) Bleed master cylinder on bench before installa­
tion. (2) Position master cylinder on studs of power
brake unit. (3) Align power brake push rod with master cylin­
der piston. (4) Install and tighten cylinder attaching nuts to
23 N-m (200 in. lbs.). (5) Connect front and rear brakelines to cylinder.
Start brakeline fittings by hand. (6) Tighten brakeline fittings to 19 N«m (170 in.

lbs.).
(7) Bleed brakes.

•

BRAKES
5 - 13
COMBINATION VALVE OPERATION

METERING (HOLD-OFF) VALVE The metering valve is used to balance brake action
between the front disc and rear drum brakes. The
valve meters (holds-off) full apply pressure to the front disc brakes until the rear brakeshoes are in full
contact with the drums.
The valve is designed to maintain front brake fluid
pressure at 3-30 psi until the hold-off limit of 117 psi is reached. At this point, the metering valve opens completely permitting full fluid apply pressure to the
front disc brakes.
PRESSURE DIFFERENTIAL SWITCH AND VALVE The pressure differential switch is connected to the
brake warning light. The switch is triggered by movement of the switch valve. The purpose of the switch is to monitor fluid pressure in the separate
front/rear brake hydraulic circuits.
A decrease or loss of fluid pressure in either hy­
draulic circuit will cause the switch valve to shuttle
forward or rearward in response to a pressure differ­ ential.
Movement of the switch valve will push the switch
plunger upward. This closes the switch internal con­ tacts completing the electrical circuit to the warning light. The switch valve will remain in an actuated
position until repair restores system pressures to nor­ mal levels.

COMBINATION VALVE TESTING
TESTING METERING VALVE Metering valve operation can be checked visually
and with the aid of a helper.
Observe the metering valve stem while a helper
applies and releases the brakes. If the valve is oper­
ating correctly, the stem will extend slightly when
the brakes are applied and retract when the brakes are released.
If the valve is faulty, replace the entire combina­
tion valve as an assembly.
TESTING PRESSURE DIFFERENTIAL SWITCH (1) Have helper sit in drivers seat to observe brake
warning light and to operate brake pedal.
(2) Raise vehicle on hoist.
(3) Connect bleed hose to left or right rear wheel
cylinder. Then immerse hose end in glass jar par­
tially filled with brake fluid.
(4) Have helper press and hold brake pedal all the
way down and observe warning light.
(a) If warning light illuminates, switch is operat­
ing correctly. (b) If light fails to illuminate, check circuit fuse,
bulb and wiring. Repair as necessary and repeat test steps (3) and (4). (5) If warning light still fails to illuminate, check
brakelight and park brake switches (and wiring) with test lamp. Repair or replace parts as necessary and test differential pressure switch operation again.
(6) If warning light still does not illuminate,
switch is faulty. Replace combination valve, bleed
brakes and verify proper switch and valve operation.

COMBINATION VALVE REMOVAL/INSTALLATION
VALVE REMOVAL (1) Raise vehicle on hoist.
(2) Mark or tag brake lines connected to valve for
assembly reference.
(3) Disconnect lines at valve (Fig. 8).
(4) Disconnect wires from differential pressure
switch.
(5) Remove bolts attaching valve to frame bracket
and remove valve.
VALVE INSTALLATION (1) Mount new valve on bracket and tighten valve
and bracket screws/nuts securely.
(2) Connect brakelines to valve. Tighten fittings to
16 N*m (145 in. lbs.)
(3) Connect wires to pressure differential switch
terminal. (4) Bleed brakes.
(5) Lower vehicle and verify proper brake opera­
tion.

BRAKE
LINES AND
HOSES

BRAKE LINE AND HOSE INSPECTION Flexible rubber hose is used at both front brakes
and at the rear axle junction block. Inspect the hoses
whenever the brake system is serviced, at every en­ gine oil change, or whenever the vehicle is in for ser­

vice.

Inspect the hoses for surface cracking, scuffing, or
worn spots. Replace any brake hose immediately if
the fabric casing of the hose is exposed by cracks or abrasion.
Also check brake hose installation. Faulty installa­
tion can result in kinked, twisted hoses, or contact with the wheels and tires or other chassis compo­
nents.
All of these conditions can lead to scuffing,
cracking and eventual failure.
The steel brake lines should be inspected periodi­
cally for evidence of corrosion, twists, kinks, leaks, or
other damage. Heavily corroded lines will eventually
rust through causing leaks. In any case, corroded or damaged brake lines should be replaced.

5
- 22
BRAKES

POWER BRAKE
VACUUM
PUMP—DIESEL ENGINE

INDEX

page

General
Information
22
Low
Vacuum
Warning
Switch
22
Pump
Adapter
Replacement
. 25

Vacuum
Pump
Diagnosis
..................
23

Vacuum
Pump
Operation
..................
23
page

Vacuum
Pump
Replacement
24

Vacuum
Pump
Serviceability
22
Vacuum—Steering
Pump
Assembly
Installation
. . 26

Vacuum—Steering
Pump
Assembly
Removal
... 23

GENERAL
INFORMATION
The power brake booster vacuum pump
and the

power steering pump
are
combined into
a
single
as­
sembly
on
diesel models
(Fig. 1).
Both pumps
are op­

erated
by a
drive gear attached
to the
vacuum pump shaft. The vacuum pump
is a
constant displacement,
vane-type pump. Vacuum
is
generated
by
four vanes
mounted
in the
pump rotor.
The
rotor
is
located
in

the pump housing
and is
pressed onto
the
pump shaft. The vacuum
and
steering pumps
are
operated
by a

single drive gear pressed onto
the
vacuum pump
shaft.
The
drive gear
is
operated
by the
camshaft
gear. The vacuum
and
power steering pump shafts
are

connected
by a
coupling. Each pump shaft
has an
adapter with drive lugs that engage
in the
coupling. The vacuum pump rotating components
are
lubri­
cated
by
engine
oil.
Lubricating
oil is
supplied
to the

pump through
an oil
line
at the
underside
of the

pump housing. The complete assembly must
be
removed
in
order
to service either pump. However,
the
power steering
pump
can
removed
and
serviced separately when necessary.

VACUUM
PUMP
SERVICEABILITY
The vacuum pump
is not a
serviceable component.
If diagnosis indicates
a
pump malfunction,
the
pump must
be
replaced
as an
assembly.
Do not
disassemble
or attempt
to
repair
the
pump.
The combined vacuum
and
steering pump assembly
must
be
removed
for
access
to
either pump. However,
the vacuum pump
can be
removed without having
to
disassemble
the
power steering pump. If
the
power steering pump requires service, simply
remove
the
assembly
and
separate
the two
pumps. Refer
to the
pump removal
and
installation proce­dures
in
this section.

LOW
VACUUM
WARNING
SWITCH
A vacuum switch
is
used
to
monitor output
of the

vacuum pump.
The
switch
is in
circuit with
the
brake warning light.
VACUUM

PUMP

DRIVE

GEAR
PUMP

ADAPTER
POWER

STEERING
PUMP

J9105-94

Fig.
1
Diesel
Vacuum
And
Power
Steering
Pump
Assembly

A vacuum hose connects
the
switch
to the
power
brake booster.
A
wire harness connects
the
switch
to
the brake warning light.
The switch
is
mounted
on the
driver side inner
fender panel just below
the
hood hinge
(Fig. 2),
b

LOW

VACUUM

WARNING
SWITCH
SWITCH

HARNESS

J9105-95

Fig.
2
Diesel
Vacuum
Switch
Location

•

BRAKES
5 - 23
VACUUM PUMP OPERATION

Vacuum pump output is transmitted to the power
brake booster through a supply hose. The hose is con­ nected to an outlet port on the pump housing and to
the check valve in the power brake booster.
Pump output ranges from a minimum of 8.5 to 25
inches vacuum. The pump rotor and vanes are rotated by the pump
drive gear. The drive gear is operated by the cam­
shaft gear. Booster vacuum level is monitored by a warning
switch (Fig. 2). The switch consists of a vacuum
chamber that measures vacuum level and a sensor in
circuit with the brake warning light. The vacuum chamber is connected to the booster
check valve by a vacuum supply hose. A wire har­
ness connects the switch sensor to the brake warning
light. If booster vacuum falls below 8.5 inches for 8-10 seconds or more, the switch sensor completes
the circuit to the warning light causing it to illumi­

nate.

VACUUM PUMP DIAGNOSIS
Vacuum pump diagnosis involves checking pump
output with a vacuum gauge. The low vacuum warn­
ing switch can also be checked with a vacuum gauge.
Refer to the diagnosis procedure in this section. A standard vacuum gauge can be used to check
pump output when necessary. Simply disconnect the
pump supply hose and connect a vacuum gauge to
the outlet port for testing purposes. Vacuum should
hold steady in a range of approximately 8.5 to 25 inches at various engine speeds.
DIAGNOSING LOW VACUUM OUTPUT CONDITION A low booster vacuum condition or a faulty low
vacuum warning switch will cause the brake warn­ ing light to illuminate. If the light does go on and in­
dicates the existence of a low vacuum condition,
check the vacuum pump, booster and warning switch
as follows:
(1) Check vacuum pump oil feed line. Verify that
line connections are secure and not leaking. If leak­ age is noted and pump is noisy, replace pump.
(2) Disconnect supply hose to booster. Connect vac­
uum gauge to this hose and run engine at various
throttle openings. Output should range from 8.5 to 25 inches vacuum. If vacuum is consistently below
8.5 inches, problem is with vacuum hoses or pump
component. If output is within specified limits, con­
tinue testing.
(3) Check booster operation as described in diagno­
sis section. Replace check valve, vacuum hoses, or
booster if necessary. However, if booster operation is correct but warning light is still on, continue testing. (4) Disconnect vacuum hose at warning switch.
Plug hose and connect hand vacuum pump to switch. (5) Start and run engine.
(6) Apply 8.5 to 9 inches of vacuum to warning
switch and observe warning light. If light goes out,
switch vacuum hose is either loose or leaking. If
light remains on, leave engine running and continue
testing.
(7) Apply 20-25 inches vacuum to switch and ob­
serve warning light operation. If light now goes out,
switch is at fault and should be replaced. If light re­
mains on, continue testing.
(8) Reconnect vacuum hoses and replace original
warning switch with known good switch. Run engine and observe warning light operation. If light is now
off, old switch is faulty. If light remains on, problem
is in wiring between switch and warning light.

VACUUM-STEERING PUMP
ASSEMBLY
REMOVAL
(1) Disconnect battery negative cable.
(2) Position drain pan under power steering pump.
(3) Disconnect vacuum and steering pump hoses
from respective pumps (Fig. 3).

Fig.
3
Vacuum
And Steering
Pump Hose
Connections

(4) Disconnect oil pressure sender wires at sender
(Fig. 4).
(5) Remove oil pressure sender (Fig. 4).
(6) Disconnect lubricating oil feed line from fitting
at underside of vacuum pump (Fig. 5).
(7) Remove lower bolt that attaches pump assem­
bly to engine block (Fig. 6).
(8) Remove bottom, inboard nut that attaches
adapter to steering pump (Fig. 6). This nut secures a
small bracket to engine block. Nut and bracket must
be removed before pump assembly can be removed from block.

•

BRAKES
5 - 29 presses the outboard shoe lining against the opposite
side of the rotor to complete braking action.
The application or release of fluid pressure causes
only a very slight movement of the caliper and pis­
ton. At brake release, the piston and caliper return
to the non-applied position.
The brakeshoes do not retract an appreciable dis­
tance from the rotor. The minimal running clearance
between the lining and rotor provides improved re­ sponse and reduced pedal travel. It also helps in pre­
venting dirt and foreign material from lodging
between the shoe and rotor surfaces.

DISC
BRAKE
LINING WEAR COMPENSATION
Normal lining wear is compensated for by extension
of the caliper piston and by lateral movement of the cal­
iper in the adapter. Piston position is also determined
in part by the square cut piston seal (Fig. 4).
Normal disc brake lining wear will cause the cali­
per piston to extend enough to maintain proper pedal height and brake response. The caliper bore will re­ceive the extra fluid needed to compensate for the ad­
ditional piston extension.
As the piston extends during brake application, the
square-cut seal is deflected outward (Fig. 4). When
brake pressure is released, the seal straightens and
returns to a normal relaxed position. Although the amount of seal movement is quite small, it is enough
to retract the piston to the necessary minimum run­
ning clearance.
As lining wear occurs, the fluid level in the front
brake reservoir will decrease. This is a normal con­ dition and only requires adding enough fluid to re­store proper level. However, when the brakeshoes are
replaced and the caliper pistons bottomed in the

bores,
the added fluid must be compensated for to avoid overfill and overflow. Removing a small
amount of fluid from the front brake reservoir before­
hand will prevent this condition.
PISTON CALIPER
DUST BOOT
RN102

Fig.
4 Caliper
Piston
Seal
Operation

DISC
BRAKE INSPECTION
Inspect the disc brake components whenever the
caliper and brakeshoes are removed during service
operations or routine maintenance. Check condition of the rotor, brakeshoe lining, caliper
and brake hoses. Front wheel bearing adjustment and
condition can also be checked at this time. The bearings
should be repacked and adjusted if necessary.

Brakeshoes
With the caliper and brakeshoes on the vehicle,
check running clearance between the rotor and
brakeshoes. The shoe lining should either be in very light contact with the rotor or have a maximum of
0.127 mm (0.005 in.) running clearance. If clearance
exceeds the stated amount, apply the brakes several
times and recheck clearance. If clearance is still ex­ cessive, either the shoes are severely worn or the cal­
iper piston could be binding in the bore.

Hoses
And Adapter Inspect condition of the brake lines and hoses. Re­
place either front hose if cut, torn, or the reinforcing
fabric is visible. Check condition of the metal brake-
lines.
Replace any line that is badly rusted, leaking
or damaged in any way.
Clean and lubricate the slide surfaces of the caliper
and adapter. Use Mopar high temperature grease for
this purpose. Also verify that the caliper adapter
bolts are secure and tightened to proper torque.
Fluid Level Check the master cylinder fluid level. Maintain
fluid level to the bottom of the indicator rings on the
reservoir. Note that front disc brake fluid level can
be expected to drop slightly as normal lining wear occurs. Use Mopar brake fluid or equivalent meeting SAE and DOT standards J1703 and DOT 3. Use
clean brake fluid from a sealed container only.

Rotors
Check the rotor surfaces for excessive wear, discol­
oration, scoring, rust, scale, or cracks. Also look for
damaged or severely rusted ventilating segments. If
pedal pulsation was experienced, check wheel bear­ ing adjustment and condition. If the bearings are OK, also check rotor runout and thickness variation.

DISC
BRAKESHOE
REMOVAL
(1) If front brakeshoes are to be replaced, remove
approximately 1/3 of fluid from master cylinder front
brake reservoir with suction gun. (2) Raise and support vehicle.
(3) Remove front wheels.
(4) Press caliper pistons to bottom of bore with
large C-clamp. Position clamp screw on outboard
brakeshoe and position clamp frame on rear of cali­
per. (5) Remove bolts securing caliper retainer clips to
caliper. Then remove clips and anti-rattle springs (Fig. 5).

5 - 31
BRAKES

Fig.
5 Removing/installing Retainer Clips and Anti-Rattle Springs (6) Remove caliper by tilting it rearward and lift­
ing up and off rotor (Fig. 6).

Fig.
6 Caliper Removal/Installation
(7) Remove outboard brakeshoe from caliper (Fig.

7).
Use pry tool to remove shoe from caliper if
flanges are tight,
(8) Remove inboard brakeshoe from caliper mount­
ing adapter (Fig. 8). (9) Support caliper on box, stool, or front control
arm. Do not allow brake hose to support weight
of caliper. This practice could damage hose.
(10) Remove O-ring from caliper adapter. •

Fig.
7
Removing
Outboard
Brakeshoe
Fig.
8 Removing/Installing Inboard
Brakeshoe

CLEANING
AND
INSPECTION
Replace bonded disc brakeshoes if the lining is
worn to a thickness of 4 mm (3/16 in.) or less. Re­
place riveted shoes if the lining is worn to within 1.5
mm (1/16 in.) of the rivet heads.
If shoe replacement is necessary, replace the shoes
on both sides at the same time. Do not replace the shoes on one side only. This practice could result in
unequal braking effort and brake pull. Note that it is
normal for the inboard shoe lining to exhibit slightly more wear than the outboard shoe lining. Check for piston seal leaks which will be evident
by brake fluid in and around the boot area and in-

•

BRAKES
5 - 31 board lining. Also check condition of the caliper pis­
ton dust boot. If leakage is evident or if the boot is
cut, torn, or damaged in any way, it will be neces­sary to overhaul the caliper.
Remove the O-ring from the caliper adapter and clean
the slide surfaces of the adapter and the machined ways on the caliper with a wire brush and sandpaper.

DISC
BRAKESHOE
INSTALLATION
(1) Install inboard brakeshoe in adapter (Fig. 8).
(2) If new brakeshoes are being installed, remove
protective paper from noise suppression gasket on outboard shoe. (3) Install and adjust outboard brakeshoe in cali­
per as follows: (a) Check vertical movement of outboard shoe in
caliper. Shoe should fit tightly and not exhibit ver­
tical movement (free play). Flange must also fit
tightly on caliper finger to eliminate free play and
prevent shoe rattle (Fig. 9). (b) If free play is evident, remove shoe from cal­
iper. (c) Bend shoe retaining flange and trial fit shoe
in caliper. Continue bending flange until shoe is
light interference fit in caliper (Fig. 10). (d) Reinstall outboard brakeshoe in caliper. If
shoe is difficult to install, use C-clamp to seat shoe
(Fig. 11).

OUTBOARD SHOE MACHINED
Fig.
9 Outboard
Brakeshoe
Positioned
On Caliper
Finger

(4) Lubricate slide surfaces of caliper mounting
adapter and machined ways on caliper with Mopar
high temperature, or multi-mileage grease.
(5) Install O-ring in adapter, if removed.
(6) Carefully install caliper over rotor and into
adapter. Do not displace or damage the piston dust boot when installing the caliper.
Fig. 10
Adjusting Outboard
Brakeshoe
Retaining

Flange
Fig.
11 Seating Outboard
Brakeshoe

(7) Align caliper in adapter and install caliper re­
tainer clips and anti-rattle springs (Fig. 5). Tighten
retainer screws to 20 N«m (180 in. lbs.) torque.
(8) Install wheels and lower vehicle.
(9) Top off master cylinder fluid level. (10) Apply brakes several times to seat caliper pis­
tons and brakeshoes and obtain firm pedal. Do this
before moving vehicle.

CALIPER
REMOVAL
(1) Raise vehicle and remove front wheels.
(2) If caliper will only be removed for shoe replace­
ment or access to other component, press caliper pis­
ton to bottom of bore with large C-clamp. (3) Remove caliper retainer clips and anti-rattle
springs. (4) Disconnect brake hose fitting at caliper. (5) Remove caliper from rotor.
(6) Remove brakeshoes from caliper and adapter.

•

BRAKES

5
- 33

BLEEDER
CALIPER
INBOARD
ANTI-RATTLE

PISTON
SPRING
RH242A
Fig.
15
Caliper Components ton tolerances
are
different
for
resin
and
steel
pistons
and
calipers.
Do not
intermix these com­
ponents
at any
time. Inspect
the
caliper piston bore.
The
bore
can be

lightly polished with Honing Tool C-4095
to
remove
very minor surface imperfections
(Fig. 16).
How­
ever,
the
caliper must
be
replaced
if the
bore
is
severely corroded, rusted, scored,
or if
polishing
would increase bore diameter more than 0.025
mm (0.001
in.).

Fig. 16 Lightly Polishing Piston Bore With Tool
C-4095

CALIPER ASSEMBLY (1) Coat caliper piston bore,
new
piston seal
and

piston with brake fluid.
(2) Install
new
piston seal
in
caliper bore.
Be
sure
seal
is
fully seated
in
groove
(Fig. 17).
(3) Install
new
dust boot
on
caliper piston. Seat
boot
in
piston groove.
(4) Start caliper piston
in
bore with
a
rotating
mo­

tion. When piston
is
started
in
seal, push piston only
part
way
into bore
(Fig. 18).
Maintain uniform pres­ sure
on
piston
to
avoid cocking
it in
bore.
Fig.
17 Installing Caliper
Piston
Seal

Fig.
18 Installing Caliper
Piston

(5) Press caliper piston
to
bottom
of
bore
and
seat
piston dust boot with Installer C-4690
and
Tool Han­ dle C-4171
(Fig. 19).
(6) Install caliper bleed screw
if
removed.

CALIPER
INSTALLATION
(1) Clean slide surfaces
of
caliper mounting
adapter with wire brush. Then lubricate adapter
slide surfaces with Mopar multi-mileage,
or
high
temperature grease.
(2) Install inboard brakeshoe
in
adapter.
(3) Install outboard brakeshoe
in
caliper.
Be
sure
shoe
is
light press
fit in
caliper. Refer
to
installation
procedure
in
Brakeshoe Replacement section. (4) Lubricate caliper slide surfaces Mopar multi-
mileage,
or
high temperature grease. (5) Install O-ring
in
adapter,
if
removed.

5
- 34
BRAKES

•
boot
>TALLir TOOL
Fig.
19 Seating
Piston
Dust
Boot

(6) Install caliper over rotor and into adapter.
(7) Align caliper in adapter and install caliper re­
tainer clips and anti-rattle springs. Tighten retainer clip screws to 20 N*m (180 in. lbs.) torque.
(8) Connect brake hose to caliper. Tighten fitting
bolt to 47 N»m (35 ft. lbs.) torque. Be sure hose is clear of chassis and suspension components and
use new seal washers to secure hose fitting to caliper. Do not reuse old washers.
(9) Fill master cylinder with Mopar brake fluid or
equivalent meeting SAE and DOT standards J1703 and DOT 3.
(10) Bleed brakes. Refer to procedure in Service
And Adjustments section.
(11) Install wheels and lower vehicle.
(12) Apply brakes several times to seat caliper pis­
tons and brakeshoes. Be sure firm pedal is obtained
before moving vehicle.

ROTOR REMOVAL
(1) Raise and support vehicle.
(2) Remove wheel and tire assembly.
(3) Remove caliper assembly. Do not allow brake
hose to support caliper. Support caliper on stool, or suspend caliper with wire attached to nearby body or
suspension component. (4) Remove grease cap, cotter pin, nut lock, adjust­
ing nut, thrust washer and outer wheel bearing. (5) Remove rotor from spindle.
(6) Remove rotor shield and seal if either is to be
serviced.
ROTOR
INSPECTION AND
SERVICE

rotor condition The rotor braking surfaces should not be refinished
unless actually necessary. Light surface rust and scale can be removed in a lathe equipped with dual
sanding discs.
Rotor surfaces can be restored by machining in a
disc brake lathe if surface scoring and wear are light.
The rotor should be replaced if:
• severely scored
• tapered
• has hard spots
• is cracked
• too thin • machining would cause rotor thickness to fall be­
low minimum thickness requirements Check rotor lateral runout and thickness variation
if pedal pulsation or an occasional low pedal condi­
tion was experienced. Measure runout with a dial in­ dicator. Measure thickness with a micrometer at a
minimum of four points around the braking surfaces.

CHECKING
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 refinishing would re­ duce thickness below the allowable minimum. Rotor
minimum thickness is usually specified on the rotor
hub (Fig. 20).
Fig.
20 Typical Location Of Rotor
Minimum

Thickness
Limit
ROTOR RUNOUT Check rotor lateral runout with Dial Indicator
C-3339 as shown in the top view (Fig. 21). Excessive