
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 contains a pressure differ-
ential valve and switch, metering valve and a rear
brake proportioning valve on 1500 and early
2500/3500 models with rear drum brakes. The combi-
nation 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.
The metering valve on the 1500 and early
2500/3500 models with rear drum brakes is used to
balance brake action between the front disc and rear
drum brakes.
The proportioning valve on the 1500 and early
2500/3500 models with rear drum brakes is used to
balance front-rear brake action at high decelerations.
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.
METERING VALVE (1500 Model)(and early
2500/3500 models with rear drum brakes)
The valve holds-off the initial pressure to the front
disc brakes until the rear brake shoes retracting
springs are overcome. The valve is designed to main-
tain front brake fluid pressure at 241-517 kPa (35-75
psi) until the hold-off limit of 310-689 kPa (100 psi)
is reached. At this point, the metering valve opens
completely permitting full fluid apply pressure to the
front disc brakes. This reduces front brake lining
wear during low deceleration stops.
PROPORTIONING VALVE (1500 Model)(and early
2500/3500 models with rear drum brakes)
The valve allows normal fluid flow during moder-
ate braking. The valve only controls fluid flow during
high decelerations brake stops, when a percentage of
rear weight is transferred to the front wheels.
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.
Fig. 3 ISO Flaring
1 - ADAPTER
2 - LUBRICATE HERE
3 - PILOT
4 - FLUSH WITH BAR
5 - TUBING
6 - BAR ASSEMBLY
BR/BEBRAKES 5 - 9
BRAKE LINES (Continued)

(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.).
(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
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. 5).
REMOVAL - FRONT
(1) Raise and support vehicle.
(2) Remove front wheel and tire assembly.
(3) Remove caliper brake hose bolt, washers and
hose (Fig. 6).
(4) Remove caliper mounting bolts.
(5) Tilt the top of the caliper up and remove it
from the adapter.
(6) Remove anti-rattle springs.
NOTE: Upper and lower anti-rattle springs are not
interchangeable.
Fig. 4 Pressure
1 - COMBINATION VALVE
2 - BRAKE LINES
3 - MOUNTING BOLT
4 - PRESSURE DIFFERENTIAL SWITCH
Fig. 5 REAR CALIPER
1 - Banjo Bolt
2 - Caliper Pin Bolts
5 - 10 BRAKESBR/BE
COMBINATION VALVE (Continued)

REMOVAL - REAR - 2500/3500
(1) Raise and support the vehicle
(2) Remove the tire and wheel assembly.
(3) Remove the disc brake caliper, (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/DISC
BRAKE CALIPERS - REMOVAL).
(4) Remove the caliper adapter bolts.
(5) Remove the rear axle shaft from the housing
on dual rear wheels, (Refer to 3 - DIFFERENTIAL &
DRIVELINE/REAR AXLE - 286RBI/AXLE SHAFTS -
REMOVAL).(6) Remove the hub and rotor assembly (C3500
only) (Fig. 31).
REMOVAL - 1500/2500 FRONT
(1) Raise and support the vehicle.
(2) Remove the wheel and tire assembly.
(3) Remove the caliper from the steering knuckle,
(Refer to 5 - BRAKES/HYDRAULIC/MECHANICAL/
DISC BRAKE CALIPERS - REMOVAL) and remove
caliper adapter assembly (Fig. 32).
NOTE: Do not allow brake hose to support caliper
adapter assembly.
Fig. 29 Checking Rotor Runout And Thickness
Variation
1 - DIAL INDICATOR
Fig. 30 Measuring Rotor Thickness
1 - MICROMETER
2 - ROTOR
Fig. 31 ROTOR / HUB REMOVAL
Fig. 32 Caliper Adapter Assembly
1 - KNUCKLE
2 - CALIPER
3 - ROTOR
BR/BEBRAKES 5 - 21
ROTORS (Continued)

(4) Remove the rotor from the hub/bearing wheel
studs.
REMOVAL - 3500 FRONT
(1) Raise and support the vehicle.
(2) Remove the wheel and tire assembly.
(3) Remove the hub extension mounting nuts and
remove the extension from the rotor if equipped.
(4) Remove the brake caliper adapter assembly.
(Refer to 5 - BRAKES/HYDRAULIC/MECHANICAL/
DISC BRAKE CALIPERS - REMOVAL).
(5) Remove the rotor assembly.
INSTALLATION - REAR - 2500/3500
(1) Install the hub to the rotor. Tighten the bolts to
128 N´m (95 ft. lbs.) (Fig. 33).
(2) Install the hub and rotor assembly.
(3) Install the rear axle shaft to the housing with
dual wheels, (Refer to 3 - DIFFERENTIAL & DRIV-
ELINE/REAR AXLE - 286RBI/AXLE SHAFTS -
INSTALLATION).
(4) Install the caliper adapter bolts.
(5) Install the disc brake caliper, (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/DISC
BRAKE CALIPERS - INSTALLATION). (Fig. 34).
(6) Install the tire and wheel assembly, (Refer to
22 - TIRES/WHEELS/WHEELS - STANDARD PRO-
CEDURE).
(7) Lower the vehicle.
INSTALLATION - 1500/2500 FRONT
(1) On models with all-wheel antilock system
(ABS), check condition of tone wheel on hub/bearing.
If teeth on wheel are damaged, hub/bearing assembly
will have to be replaced (tone wheel is not serviced
separately).
(2) Install rotor onto the hub/bearing wheel studs.
(3) Install the caliper adapter assembly,(Refer to 5
- BRAKES/HYDRAULIC/MECHANICAL/DISC
BRAKE CALIPERS - INSTALLATION) and tighten
adapter bolts to:
²LD 1500: 176 N´m (130 ft lbs.)
²HD 2500: 285 N´m (210 ft lbs.)
(4) Install the wheel and tire assembly, (Refer to
22 - TIRES/WHEELS/WHEELS - STANDARD PRO-
CEDURE) and lower vehicle.
(5) Apply brakes several times to seat brake shoes.
Be sure to obtain firm pedal before moving vehicle.
INSTALLATION - 3500 FRONT
(1) Position the rotor on the hub/bearing.
(2) Install the brake caliper adapter assembly
(Refer to 5 - BRAKES/HYDRAULIC/MECHANICAL/
DISC BRAKE CALIPERS - INSTALLATION) and
tighten adapter bolts to 285 N´m (210 ft. lbs).
(3) Install the wheel and tire assemblies, (Refer to
22 - TIRES/WHEELS/WHEELS - STANDARD PRO-
CEDURE).
(4) Remove the support and lower the vehicle.
(5) Apply brakes several times to seat brake shoes
and caliper piston. Do not move vehicle until firm
brake pedal is obtained.
Fig. 33 ROTOR TO HUB
1 - Hub Bolts
2 - Socket
Fig. 34 ROTOR INSTALLED
5 - 22 BRAKESBR/BE
ROTORS (Continued)

REMOVAL - REAR BRAKE SHOES-11 inch
(1) Raise and support vehicle.
(2) Remove wheel and tire assembly.
(3) Remove clip nuts securing brake drum to wheel
studs.
(4) Remove drum. If drum is difficult to remove,
remove rear plug from access hole in support plate.
Back-off self adjusting by inserting a thin screw-
driver into access hole and push lever away from
adjuster screw star wheel. Then insert an adjustertool into brake adjusting hole rotate adjuster star
wheel to retract brake shoes.
(5) Vacuum brake components to remove brake lin-
ing dust.
(6) Remove shoe return springs with brake spring
plier tool (Fig. 45).
Fig. 42 Outboard Brake Shoe
1 - OUTBOARD SHOE
2 - CALIPER ADAPTER
Fig. 43 Top Anti-Rattle Spring
1 - CALIPER ADAPTER
2 - ANTI-RATTLE SPRING
Fig. 44 Bottom Anti-Rattle Spring
1 - ANTI-RATTLE SPRING
2 - CALIPER ADAPTER
Fig. 45 Shoe Return Springs
1 - SHOE RETURN SPRING
2 - SPECIAL TOOL (REMOVING AND INSTALLING)
3 - SHOE RETURN SPRING
4 - ADJUSTER CABLE
5 - LEVER SPRING
6 - ADJUSTER LEVER
7 - SHOE TO SHOE SPRING
8 - ANTI-RATTLE SPRING
BR/BEBRAKES 5 - 25
BRAKE PADS/SHOES (Continued)

INSTALLATION
(1) Apply thin coat of silicone sealer to wheel cyl-
inder mounting surface of support plate (Fig. 59).
Sealer prevents road splash from entering brake
drum past cylinder.
(2) Start brake line in cylinder inlet by hand. Do
not tighten fitting at this time.
(3) Mount wheel cylinder on support plate and
install cylinder attaching screws. Tighten screws to
20 N´m (15 ft. lbs.).
(4) Tighten brake line fitting to 13 N´m (115 in.
lbs.).
(5) Install brake shoe components.
(6) Adjust brake shoes to drum using brake gauge.
(7) Install brake drum.
(8) Bleed base brake system, (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL - STAN-
DARD PROCEDURE).
(9) Install wheel and tire assemblies, (Refer to 22 -
TIRES/WHEELS/WHEELS - STANDARD PROCE-
DURE) and lower vehicle.
SUPPORT PLATE
REMOVAL
(1) Remove wheel and tire assemblies.
(2) Remove brake drums
(3) Remove axle shaft, (Refer to 3 - DIFFEREN-
TIAL & DRIVELINE/REAR AXLE - 9 1/4/AXLE
SHAFTS - REMOVAL).
(4) Remove brake shoes and hardware for access to
parking brake cable.
(5) Remove parking brake cable from support
plate.(6) Disconnect brake line at wheel cylinder and
remove cylinder.
(7) Remove bolts attaching support plate to axle
and remove support plate.
INSTALLATION
(1) Apply thin bead of silicone sealer around axle
mounting surface of support plate.
(2) Install support plate on axle flange. Tighten
attaching bolts to 47-68 N´m (35-50 ft. lbs.).
(3) Apply thin bead of silicone sealer around wheel
cylinder mounting surface. Install wheel cylinder on
new support plate.
(4) Install parking brake cable in support plate.
(5) Install brake shoes and hardware.
(6) Install axle shaft, (Refer to 3 - DIFFEREN-
TIAL & DRIVELINE/REAR AXLE - 9 1/4/AXLE
SHAFTS - INSTALLATION).
(7) Adjust brake shoes to drum with brake gauge.
(8) Install brake drums.
(9) Fill and bleed brake system, (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL - STAN-
DARD PROCEDURE).
(10) Install wheel and tire assemblies, (Refer to 22
- TIRES/WHEELS/WHEELS - STANDARD PROCE-
DURE) and lower vehicle.
DRUM
DESCRIPTION
All 1500 models and early year production
2500/3500 are equipped with rear drum brake assem-
blies. They are two-shoe, duo-servo units with an
automatic adjuster mechanism.
Drum brake assemblies used:
²1500 models: 11 x 2.25 in.
²2500/3500 models: 12 1/8 x3.5 in.
The drum brakes are a semi-floating, self-energiz-
ing, servo action design. The brake shoes are not
fixed on the support plate. This type of brake allows
the shoes to pivot and move vertically to a certain
extent.
OPERATION
In operation, fluid apply pressure causes the wheel
cylinder pistons to move outward. This movement is
transferred directly to the brake shoes by the cylin-
der connecting links. The resulting brake shoe expan-
sion brings the lining material into contact with the
rotating brake drum.
Two forces affect the brake shoes once they contact
the drum. The first force being hydraulic pressure
exerted through the wheel cylinder pistons. And the
second force is the friction generated turning torque
of the rotating drum.
Fig. 59 Wheel Cylinder Mounting Surface
1 - CYLINDER MOUNTING SURFACE
2 - SUPPORT PLATE
3 - APPLY THIN SEALER COAT HERE
5 - 32 BRAKESBR/BE
WHEEL CYLINDERS (Continued)

REMOVAL
(1) Remove transmission and transfer case, if
equipped. Refer to Group 21, Transmission and
Transfer Case, for proper procedures.
(2) Remove clutch housing, for NV4500 equipped
vehicles.
(3) Disconnect release bearing from release fork
and remove bearing (Fig. 25).
INSTALLATION
(1) Inspect bearing slide surface on transmission
front bearing retainer. Replace retainer if slide sur-
face is scored, worn, or cracked.(2) Inspect release lever and pivot stud. Be sure
stud is secure and in good condition. Be sure fork is
not distorted or worn. Replace fork spring clips if
bent or damaged.
(3) Lubricate input shaft splines, bearing retainer
slide surface, lever pivot ball stud, and release lever
pivot surface with Moparthigh temperature bearing
grease.
(4) Install release fork and release bearing (Fig.
26). Be sure fork and bearing are properly secured by
spring clips. Also be sure that the release fork is
installed properly. The rear side of the release lever
has one end with a raised area. This raised area goes
toward the slave cylinder side of the transmission.
(5) Install clutch housing, if removed.
(6) Install transmission and transfer case, if
equipped. Refer to Group 21, Transmission and
Transfer Case, for proper procedures.
PRESSURE PLATE
DESCRIPTION
The clutch pressure plate assembly is a diaphragm
type with a one-piece spring and multiple release fin-
gers. The pressure plate release fingers are preset
during manufacture and are not adjustable. The
assembly also contains the cover, pressure plate, and
fulcrum components.
Various sizes and designs of clutch covers are used
for the different engine and transmission combina-
tions. The currently used clutch covers and applica-
tions are listed below.
Fig. 24 Clutch Release Bearing
1 - RELEASE BEARING
2 - RELEASE FORK
Fig. 25 Clutch Release Components
1 - CONED WASHER
2 - CLUTCH HOUSING
3 - RELEASE FORK
4 - RELEASE BEARING AND SLEEVE
5 - PIVOT 23 N´m (200 IN. LBS.)
6 - SPRING
Fig. 26 Clutch Release Fork And
1 - PIVOT BALL
2 - FORK
3 - SLAVE CYLINDER OPENING
4 - BEARING
BR/BECLUTCH 6 - 15
CLUTCH RELEASE BEARING (Continued)

and compressed air to the back (engine side) of the
radiator to flush the radiator and/or A/C condenser of
debris.
INSPECTION
Inspect the radiator side tanks for cracks, broken
or missing fittings also inspect the joint where the
tanks seam up to the radiator core for signs of leak-
age and/or deteriorating seals.
Inspect radiator core for corroded, bent or missing
cooling fins. Inspect the core for bent or damaged
cooling tubes.
INSTALLATION
(1) Position fan shroud over the fan blades rear-
ward towards engine.
(2) Install rubber insulators to alignment dowels
at lower part of radiator.
(3) Lower the radiator into position while guiding
the two alignment dowels into lower radiator sup-
port. Different alignment holes are provided in the
lower radiator support for each engine application.
(4) Install two upper radiator mounting bolts.
Tighten bolts to 11 N´m (95 in. lbs.) torque.
(5) Position the rubber shields to the sides of radi-
ator. Install the plastic clips retaining the rubber
shields to the sides of radiator.
(6) Connect both radiator hoses and install hose
clamps.
(7) Install windshield washer reservoir tank.
(8) Position fan shroud to flanges on sides of radi-
ator. Install fan shroud mounting bolts (Fig. 34).
Tighten bolts to 6 N´m (50 in. lbs.) torque.
(9) Install coolant reserve/overflow tank hose to
radiator filler neck nipple.
(10) Install coolant reserve/overflow tank to fan
shroud (fits into T-slots on shroud).
(11) Install battery negative cables.
(12) Position heater controls tofull heatposition.
(13) Fill cooling system with coolant (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(14) Operate engine until it reaches normal tem-
perature. Check cooling system fluid levels.
RADIATOR - 8.0L
DESCRIPTION
The radiator is a aluminum cross-flow design with
horizontal tubes through the radiator core and verti-
cal plastic side tanks (Fig. 36).
This radiator contains an internal transmission oil
cooler only on the V-10 gas engine and the 5.9L die-
sel engine combinations.
OPERATION
The radiator supplies sufficient heat transfer using
the cooling fins interlaced between the horizontal
tubes in the radiator core to cool the engine.
DIAGNOSIS AND TESTINGÐRADIATOR
COOLANT FLOW
Use the following procedure to determine if coolant
is flowing through the cooling system.
(1) Idle engine until operating temperature is
reached. If the upper radiator hose is warm to the
touch, the thermostat is opening and coolant is flow-
ing to the radiator.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. USING A RAG TO
COVER THE RADIATOR PRESSURE CAP, OPEN
RADIATOR CAP SLOWLY TO THE FIRST STOP. THIS
WILL ALLOW ANY BUILT-UP PRESSURE TO VENT
TO THE RESERVE/OVERFLOW TANK. AFTER PRES-
SURE BUILD-UP HAS BEEN RELEASED, REMOVE
CAP FROM FILLER NECK.
(2) Drain a small amount of coolant from the radi-
ator until the ends of the radiator tubes are visible
through the filler neck. Idle the engine at normal
operating temperature. If coolant is flowing past the
exposed tubes, the coolant is circulating.
Fig. 36 Cross Flow RadiatorÐTypical
1 - COOLING TUBES
2 - TANKS
BR/BEENGINE 7 - 61
RADIATOR - 3.9L/5.2L/5.9L (Continued)