2002 DODGE RAM brake light

mile or two. However, if the lining is both soaked and
dirt contaminated, cleaning and/or replacement will
be necessary.
BRAKE LINING CONTAMINATION
Brake lining contamination is mostly a product of
leaking calipers or wheel cylinders, worn seals, driv-
ing through deep water puddles, or lining that has
become covered with grease and grit during repair.
Contaminated lining should be replaced to avoid fur-
ther brake problems.
WHEEL AND TIRE PROBLEMS
Some conditions attributed to brake components
may actually be caused by a wheel or tire problem.
A damaged wheel can cause shudder, vibration and
pull. A worn or damaged tire can also cause pull.
Severely worn tires with very little tread left can
produce a grab-like condition as the tire loses and
recovers traction. Flat-spotted tires can cause vibra-
tion and generate shudder during brake operation. A
tire with internal damage such as a severe bruise,
cut, or ply separation can cause pull and vibration.
BRAKE NOISES
Some brake noise is common with rear drum
brakes and on some disc brakes during the first few
stops after a vehicle has been parked overnight or
stored. This is primarily due to the formation of trace
corrosion (light rust) on metal surfaces. This light
corrosion is typically cleared from the metal surfaces
after a few brake applications causing the noise to
subside.
BRAKE SQUEAK/SQUEAL
Brake squeak or squeal may be due to linings that
are wet or contaminated with brake fluid, grease, or
oil. Glazed linings and rotors with hard spots can
also contribute to squeak. Dirt and foreign material
embedded in the brake lining will also cause squeak/
squeal.
A very loud squeak or squeal is frequently a sign of
severely worn brake lining. If the lining has worn
through to the brake shoes in spots, metal-to-metal
contact occurs. If the condition is allowed to continue,
rotors and drums can become so scored that replace-
ment is necessary.
BRAKE CHATTER
Brake chatter is usually caused by loose or worn
components, or glazed/burnt lining. Rotors with hard
spots can also contribute to chatter. Additional causes
of chatter are out-of-tolerance rotors, brake lining not
securely attached to the shoes, loose wheel bearings
and contaminated brake lining.THUMP/CLUNK NOISE
Thumping or clunk noises during braking are fre-
quentlynotcaused by brake components. In many
cases, such noises are caused by loose or damaged
steering, suspension, or engine components. However,
calipers that bind on the slide surfaces can generate
a thump or clunk noise. In addition, worn out,
improperly adjusted, or improperly assembled rear
brake shoes can also produce a thump noise.
STANDARD PROCEDURE
STANDARD PROCEDURE - MANUAL BLEEDING
Use Mopar brake fluid, or an equivalent quality
fluid meeting SAE J1703-F and DOT 3 standards
only. Use fresh, clean fluid from a sealed container at
all times.
(1) Remove reservoir filler caps and fill reservoir.
(2) If calipers, or wheel cylinders were overhauled,
open all caliper and wheel cylinder bleed screws.
Then close each bleed screw as fluid starts to drip
from it. Top off master cylinder reservoir once more
before proceeding.
(3) Attach one end of bleed hose to bleed screw
and insert opposite end in glass container partially
filled with brake fluid (Fig. 1). Be sure end of bleed
hose is immersed in fluid.
(4)
Open up bleeder, then have a helper press down
the brake pedal. Once the pedal is down close the
bleeder. Repeat bleeding until fluid stream is clear and
free of bubbles. Then move to the next wheel.
Fig. 1 Bleed Hose Setup
1 - BLEED HOSE
2 - FLUID CONTAINER PARTIALLY FILLED WITH FLUID
BR/BEBRAKES - BASE 5 - 7
HYDRAULIC/MECHANICAL (Continued)

STANDARD PROCEDURE - PRESSURE
BLEEDING
Use Mopar brake fluid, or an equivalent quality
fluid meeting SAE J1703-F and DOT 3 standards
only. Use fresh, clean fluid from a sealed container at
all times.
If pressure bleeding equipment will be used, the
front brake metering valve will have to be held open
to bleed the front brakes. The valve stem is located
in the forward end or top of the combination valve.
The stem must either be pressed inward, or held out-
ward slightly. A spring clip tool or helper is needed to
hold the valve stem in position.
Follow the manufacturers instructions carefully
when using pressure equipment. Do not exceed the
tank manufacturers pressure recommendations. Gen-
erally, a tank pressure of 15-20 psi is sufficient for
bleeding.
Fill the bleeder tank with recommended fluid and
purge air from the tank lines before bleeding.
Do not pressure bleed without a proper master cyl-
inder adapter. The wrong adapter can lead to leak-
age, or drawing air back into the system. Use
adapter provided with the equipment or Adapter
6921.
BRAKE LINES
STANDARD PROCEDURE
STANDARD PROCEDURE - DOUBLE INVERTED
FLARING
A preformed metal brake tube is recommended and
preferred for all repairs. However, double-wall steel
tube can be used for emergency repair when factory
replacement parts are not readily available.
(1) Cut off damaged tube with Tubing Cutter.
(2) Ream cut edges of tubing to ensure proper
flare.
(3) Install replacement tube nut on the tube.
(4) Insert tube in flaring tool.
(5) Place gauge form over the end of the tube.
(6) Push tubing through flaring tool jaws until
tube contacts recessed notch in gauge that matches
tube diameter.
(7) Tighten the tool bar on the tube
(8) Insert plug on gauge in the tube. Then swing
compression disc over gauge and center tapered flar-
ing screw in recess of compression disc (Fig. 2).
(9) Tighten tool handle until plug gauge is
squarely seated on jaws of flaring tool. This will start
the inverted flare.
(10) Remove the plug gauge and complete the
inverted flare.
STANDARD PROCEDURE - ISO FLARING
A preformed metal brake tube is recommended and
preferred for all repairs. However, double-wall steel
tube can be used for emergency repair when factory
replacement parts are not readily available.
To make a ISO flare use an ISO flaring tool kit.
(1) Cut off damaged tube with Tubing Cutter.
(2) Remove any burrs from the inside of the tube.
(3) Install tube nut on the tube.
(4) Position the tube in the flaring tool flush with
the top of the tool bar (Fig. 3). Then tighten the tool
bar on the tube.
(5) Install the correct size adaptor on the flaring
tool yoke screw.
(6) Lubricate the adaptor.
(7) Align the adaptor and yoke screw over the tube
(Fig. 3).
(8) Turn the yoke screw in until the adaptor is
squarely seated on the tool bar.
COMBINATION VALVE
DESCRIPTION
The combination valve/rear brake proportioning
valve are not repairable and must be replaced as an
assembly.
The pressure differential switch is connected to the
brake warning lamp.
Fig. 2 Inverted Flare Tools
5 - 8 BRAKES - BASEBR/BE
HYDRAULIC/MECHANICAL (Continued)

OPERATION
PRESSURE DIFFERENTIAL SWITCH
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
hydraulic circuit will cause the switch valve to shut-
tle forward or rearward in response to the pressure
differential. Movement of the switch valve will push
the switch plunger upward. This closes the switch
internal contacts completing the electrical circuit to
the warning lamp. The switch valve may remain in
an actuated position until repair restores system
pressures to normal levels.
DIAGNOSIS AND TESTING - COMBINATION
VALVE
Pressure Differential Switch
(1) Have helper sit in drivers seat to apply brake
pedal and observe red brake warning light.
(2) Raise vehicle on hoist.(3) Connect bleed hose to a rear wheel cylinder
and immerse hose end in container partially filled
with brake fluid.
(4) Have helper press and hold brake pedal to floor
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. The parking brake switch can be
used to aid in identifying whether or not the brake
light bulb and fuse is functional. Repair or replace
parts as necessary and test differential pressure
switch operation again.
(5) If warning light still does not illuminate,
switch is faulty. Replace combination valve assembly,
bleed brake system and verify proper switch and
valve operation.
REMOVAL
(1) Remove pressure differential switch wire con-
nector (Fig. 4) from the valve.
(2) Remove the brake lines from the valve.
(3) Remove the valve mounting bolt and remove
the valve from the bracket.
INSTALLATION
(1) Position the valve on the bracket and install
the mounting bolt. Tighten the mounting bolt to 23
N´m (210 in. lbs.).
(2) Install the brake lines into the valve and
tighten to 19-23 N´m (170-200 in. lbs.).
Fig. 3 ISO Flaring
1 - ADAPTER
2 - LUBRICATE HERE
3 - PILOT
4 - FLUSH WITH BAR
5 - TUBING
6 - BAR ASSEMBLY
Fig. 4 Pressure
1 - COMBINATION VALVE
2 - BRAKE LINES
3 - MOUNTING BOLT
4 - PRESSURE DIFFERENTIAL SWITCH
BR/BEBRAKES - BASE 5 - 9
COMBINATION VALVE (Continued)

(3) Connect the pressure differential switch wire
connector.
(4) Bleed base brake system, (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL - STAN-
DARD PROCEDURE).
DISC BRAKE CALIPERS
DESCRIPTION
The caliper is a one-piece casting. The piston bores
are located in the inboard side. A square-cut piston
seal is located in a machined groove in the cylinder
bore.
The caliper pistons dust boot prevents dirt, water
and road splash from entering the piston bore. The
boot is seated in a groove machined at the outer end
of the caliper piston. The boot retaining flange is
seated in a counterbore machined in the outer end of
the caliper piston bore.
Ventilated disc brake rotors are used for all appli-
cations. The rotors are serviceable and can be
machined to restore surface finish when necessary.
OPERATION
When the brakes are applied fluid pressure is
exerted against the caliper piston. The fluid pressure
is exerted equally and in all directions. This means
pressure exerted against the caliper piston and
within the caliper bore will be equal (Fig. 5).
Fluid pressure applied to the piston is transmitted
directly to the inboard brake shoe. This forces the
shoe lining against the inner surface of the disc
brake rotor. At the same time, fluid pressure within
the piston bore forces the caliper to slide inward on
the mounting bolts. This action brings the outboard
brake shoe lining into contact with the outer surface
of the disc brake rotor.
In summary, fluid pressure acting simultaneously
on both piston and caliper, produces a strong clamp-
ing action. When sufficient force is applied, friction
will attempt to stop the rotors from turning and
bring the vehicle to a stop.
Application and release of the brake pedal gener-
ates only a very slight movement of the caliper and
piston. Upon release of the pedal, the caliper and pis-
ton return to a rest position. The brake shoes do not
retract an appreciable distance from the rotor. In
fact, clearance is usually at, or close to zero. The rea-
sons for this are to keep road debris from getting
between the rotor and lining and in wiping the rotor
surface clear each revolution.
The caliper piston seal controls the amount of pis-
ton extension needed to compensate for normal lining
wear.During brake application, the seal is deflected out-
ward by fluid pressure and piston movement (Fig. 6).
When the brakes (and fluid pressure) are released,
the seal relaxes and retracts the piston.
The amount of piston retraction is determined by
the amount of seal deflection. Generally the amount
is just enough to maintain contact between the pis-
ton and inboard brake shoe.
REMOVAL
REMOVAL - REAR
(1) Raise and support the vehicle.
(2) Remove the tire and wheel assembly.
(3) Compress the disc brake caliper using tool
#C4212F.
(4) Remove the caliper pin bolts.
(5) Remove the banjo bolt and discard the copper
washer.
CAUTION: Never allow the disc brake caliper to
hang from the brake hose. Damage to the brake
hose with result. Provide a suitable support to hang
the caliper securely.
(6) Remove the rear disc brake caliper (Fig. 7).
Fig. 5 Brake Caliper Operation
1 - CALIPER
2 - PISTON
3 - PISTON BORE
4 - SEAL
5 - INBOARD SHOE
6 - OUTBOARD SHOE
5 - 10 BRAKES - BASEBR/BE
COMBINATION VALVE (Continued)

CAUTION: If the caliper piston is replaced, install
the same type of piston in the caliper. Never inter-
change phenolic resin and steel caliper pistons.
The pistons, seals, seal grooves, caliper bore and
piston tolerances are different.
The bore can belightlypolished with a brake
hone to remove very minor surface imperfections
(Fig. 14). The caliper should be replaced if the bore is
severely corroded, rusted, scored, or if polishing
would increase bore diameter more than 0.025 mm
(0.001 inch).
ASSEMBLY
CAUTION: Dirt, oil, and solvents can damage cali-
per seals. Insure assembly area is clean and dry.
(1) Lubricate caliper pistons, piston seals and pis-
ton bores with clean, fresh brake fluid.
(2) Install new piston seals into caliper bores (Fig.
15).
NOTE: Verify seal is fully seated and not twisted.
(3) Lightly lubricate lip of new boot with silicone
grease. Install boot on piston and work boot lip into
the groove at the top of piston.
(4) Stretch boot rearward to straighten boot folds,
then move boot forward until folds snap into place.
(5) Install piston into caliper bore and press piston
down to the bottom of the caliper bore by hand or
with hammer handle (Fig. 16).
(6) Seat dust boot in caliper (Fig. 17) with Handle
C-4171 and Installer:
²HD 56 mm caliper: Installer C-4340
²LD 54 mm caliper: Installer C-3716-A
(7) Install the second piston and dust boot.
(8) Lubricate caliper mounting bolt bushings, boot
seals and bores with Mopar brake grease or Dow
Corningt807 grease only.
CAUTION: Use of alternative grease may cause
damage to the boots seals.
(9) Install the boot seals into the caliper seal bores
and center the seals in the bores.
Fig. 13 Bushings And Boot Seals
1 - CALIPER
2 - BUSHING
3 - BOOT SEAL
Fig. 14 Polishing Piston Bore
1 - HONE
2 - CALIPER
3 - PISTON BORE
Fig. 15 Piston Seal
1 - CALIPER
2 - PISTON BORE
3 - PISTON SEAL
BR/BEBRAKES - BASE 5 - 13
DISC BRAKE CALIPERS (Continued)

PEDAL
DESCRIPTION
The brake booster is operated by a suspended type
brake pedal. The pedal pivots on a shaft located in a
mounting bracket attached to the dash panel. The
pedal shaft is supported by bushings in the pedal
and mounting bracket. The brake pedal is attached
to the booster push rod.
OPERATION
When the pedal is depressed, the primary booster
push rod is depressed which move the booster sec-
ondary rod. The booster secondary rod depress the
master cylinder piston.
REMOVAL
(1) Remove knee bolster, (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - REMOVAL).
(2) Remove brake lamp switch, (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/BRAKE
LAMP SWITCH - REMOVAL).
(3) Remove switches from tabs on brake lamp
switch bracket.
(4) Remove brake lamp switch bracket bolts and
remove bracket (Fig. 25).
(5) Remove clip and washer attaching booster push
rod and slide push rod off pedal.
(6) Remove E-clip from passenger side of pedal
shaft (Fig. 26). Use flat blade screwdriver to pry clip
out of shaft groove.
(7) Push shaft toward driver side of bracket just
enough to expose opposite E-clip. Then remove E-clip
with flat blade screwdriver.(8) Push pedal shaft back and out of passenger
side of bracket (Fig. 26).
(9) Remove pedal shaft, brake pedal, wave washer
and bushings from vehicle.
INSTALLATION
(1) Replace bracket and pedal bushings if neces-
sary. Lubricate shaft bores in bracket and pedal
before installing bushings with Mopar Multi-mileage
silicone grease.
(2) Apply liberal quantity of Mopar multi-mileage
grease to pedal shaft and to pedal and bracket bush-
ings.
(3) Position brake pedal in mounting bracket.
(4) Slide pedal shaft into bracket and through
pedal from passenger side.
(5) Push pedal shaft out driver side of mounting
bracket just enough to allow installation of retaining
E-clip.
(6) Install the wave washer between the bracket
and the pedal bushing on the passenger side.
(7) Push pedal shaft back toward passenger side of
bracket and install remaining E-clip on pedal shaft.
(8) Install booster push rod on brake pedal. Secure
push rod to pedal with washer and retaining clip.
(9) Install brake lamp switch bracket and switch,
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
Fig. 25 Brake Lamp Switch Bracket
1 - PEDAL BRACKET
2 - BRAKELIGHT SWITCH BRACKET
3 - BRACKET SCREWS (2)
Fig. 26 Brake Pedal Mounting (With Automatic
Transmission)
1 - PEDAL SHAFT
2 - SHAFT RETAINING E-CLIPS (2)
3 - BRAKE PEDAL
4 - PEDAL BUSHING (2)
5 - PEDAL MOUNTING BRACKET
BR/BEBRAKES - BASE 5 - 17

(7) Install the hydraulic booster pressure lines to
the bracket and booster.
(8) Tighten the pressure lines to 41 N´m (30 ft.
lbs.).
NOTE: Inspect o-rings on the pressure line fittings
to insure they are in good condition before installa-
tion. Replace o-rings if necessary.
(9) Install the return hose to the booster.(10) Bleed base brake system, (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL - STAN-
DARD PROCEDURE).
(11) Fill the power steering pump with fluid,
(Refer to 19 - STEERING/PUMP - STANDARD PRO-
CEDURE).
CAUTION: Use only MOPAR power steering fluid or
equivalent. Do not use automatic transmission fluid
and do not overfill.
(12) Bleed the hydraulic booster.
ROTORS
DIAGNOSIS AND TESTING
DISC BRAKE ROTOR
The rotor braking surfaces should not be refinished
unless necessary.
Light surface rust and scale can be removed with a
lathe equipped with dual sanding discs. The rotor
surfaces can be restored by machining with a disc
brake lathe if surface scoring and wear are light.
Replace the rotor for the following conditions:
²Severely Scored
²Tapered
²Hard Spots
²Cracked
²Below Minimum Thickness
Fig. 28 Master Cylinder And Booster
1 - MASTER CYLINDER
2 - RETURN LINE
3 - LINE FROM PUMP
4 - HYDRAULIC BOOSTER
5 - LINE TO GEAR
Fig. 29 Booster Push Rod
1 - BOOSTER PUSH ROD
2 - WASHER
3 - CLIP
4 - PEDAL
Fig. 30 Booster Mounting
1 - STEERING COLUMN
2 - MOUNTING NUTS
3 - BOOSTER PEDAL ROD
4 - MOUNTING NUTS
5 - 20 BRAKES - BASEBR/BE
POWER BRAKE BOOSTER (Continued)

(7) Install caliper, (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/DISC BRAKE CALIPERS
- INSTALLATION) (Refer to 5 - BRAKES/HYDRAU-
LIC/MECHANICAL/DISC BRAKE CALIPERS -
INSTALLATION).
(8) Install wheel and tire assemblies and lower
vehicle, (Refer to 22 - TIRES/WHEELS/WHEELS -
STANDARD PROCEDURE).
(9) Apply brakes several times to seat caliper pis-
tons and brake shoes and obtain firm pedal.
(10) Top off master cylinder fluid level.
INSTALLATION - FRONT
(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 shoe in adapter.
(6) Install outboard brake shoe in adapter.
(7) Tilt the bottom of the caliper over rotor and
under adapter. Then push the top 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.
MASTER CYLINDER
DESCRIPTION
A two-piece master cylinder is used on all models.
The cylinder body containing the primary and sec-
ondary pistons is made of aluminum. The removable
fluid reservoir is made of nylon reinforced with glass
fiber. The reservoir stores reserve brake fluid for the
hydraulic brake circuits. The reservoir is the only
serviceable component.
The fluid compartments of the nylon reservoir are
interconnected to permit fluid level equalization.
However, the equalization feature does not affect cir-
cuit separation in the event of a front or rear brake
malfunction. The reservoir compartments will retain
enough fluid to operate the functioning hydraulic cir-
cuit.Care must be exercised when removing/installing
the master cylinder connecting lines. The threads in
the cylinder fluid ports can be damaged if care is not
exercised. Start all brake line fittings by hand to
avoid cross threading.
The cylinder reservoir can be replaced when neces-
sary. However, the aluminum body section of the
master cylinder is not a repairable component.
NOTE: If diagnosis indicates that an internal mal-
function has occurred, the aluminum body section
must be replaced as an assembly.
OPERATION
The master cylinder bore contains a primary and
secondary piston. The primary piston supplies
hydraulic pressure to the front brakes. The secondary
piston supplies hydraulic pressure to the rear brakes.
DIAGNOSIS AND TESTING - MASTER
CYLINDER/POWER BOOSTER
(1) Start engine and check booster vacuum hose
connections. A hissing noise indicates vacuum leak.
Correct any vacuum leak before proceeding.
(2) Stop engine and shift transmission into Neu-
tral.
(3) Pump brake pedal until all vacuum reserve in
booster is depleted.
(4) Press and hold brake pedal under light foot
pressure. The pedal should hold firm, if the pedal
falls away master cylinder is faulty (internal leak-
age).
(5) Start engine and note pedal action. It should
fall away slightly under light foot pressure then hold
firm. If no pedal action is discernible, power booster,
vacuum supply, or vacuum check valve is faulty. Pro-
ceed to the POWER BOOSTER VACUUM TEST.
(6) If the POWER BOOSTER VACUUM TEST
passes, rebuild booster vacuum reserve as follows:
Release brake pedal. Increase engine speed to 1500
rpm, close the throttle and immediately turn off igni-
tion to stop engine.
(7) Wait a minimum of 90 seconds and try brake
action again. Booster should provide two or more vac-
uum assisted pedal applications. If vacuum assist is
not provided, booster is faulty.
POWER BOOSTER VACUUM TEST
(1) Connect vacuum gauge to booster check valve
with short length of hose and T-fitting (Fig. 47).
(2) Start and run engine at curb idle speed for one
minute.
(3) Observe the vacuum supply. If vacuum supply
is not adequate, repair vacuum supply.
5 - 26 BRAKES - BASEBR/BE
BRAKE PADS/SHOES (Continued)