1999 DODGE RAM differential


* B RAK E S YSTE M U NIF O RM IN SPEC TIO N G UID ELIN ES *

1 999 D odge P ic ku p R 1500
GENERAL INFORMATION
Brake Systems - Motorist Assurance Program
Standards For Automotive Repair
All Makes & Models
CONTENTS
OVERVIEW OF MOTORIST ASSURANCE PROGRAM
OVERVIEW OF SERVICE REQUIREMENTS AND SUGGESTIONS
ACCELEROMETERS (G SENSOR OR LATERAL)
ACCUMULATORS
ANCHOR PINS
ANTI-LOCK BRAKE SYSTEMS
BACKING PLATES
BRAKE FLUID
BRAKE FRICTION MATERIAL
BRAKE PADS
BRAKE PEDALS
BRAKE SHOES
BRAKE SHOE HARDWARE
BRAKE STOPLIGHT SWITCHES
BULB SOCKETS
BULBS AND LEDS
CALIPER HARDWARE
CALIPERS
CONTROLLERS
DIGITAL RATIO AXLE CONTROLLERS AND BUFFERS (DRAC AND DRAB)
DISABLE SWITCHES
DRUMS
ELECTRICAL PUMPS AND MOTORS
ELECTRONIC CONTROLLERS
FLUID
FLUID LEVEL SENSOR SWITCHES
FOUR WHEEL DRIVE SWITCHES
FRICTION MATERIAL
G SENSORS
HOSES
HYDRAULIC MODULATORS
HYDRO-BOOSTERS
HYDRO-ELECTRIC BOOSTERS (POWERMASTER)
IGNITION DISABLE SWITCHES
LATERAL ACCELERATION SWITCHES
LEDS
LENSES
MASTER CYLINDERS
MODULATORS
MOTORS
PARKING BRAKE SWITCHES
PARKING BRAKE SYSTEMS
PADS
PEDAL TRAVEL SWITCHES
PEDALS
POWERMASTER
PUMPS
PRESSURE DIFFERENTIAL SWITCHES
PRESSURE SWITCHES
RELAYS
ROTORS
SELF-ADJUSTING SYSTEMS

missing ................ C .. Require replacement of missing
parts.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
(1) - Inoperative includes intermittent operation.









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PADS
See FRICTION MATERIAL .
PEDAL TRAVEL SWITCHES
See SWITCHES.
PEDALS
See BRAKE PEDALS.
POWERMASTER
See HYDRO-BOOSTERS .
PUMPS
See ELECTRICAL PUMPS AND MOTORS .
PRESSURE DIFFERENTIAL SWITCHES
See SWITCHES.
PRESSURE SWITCHES
See SWITCHES.
RELAYS
NOTE: Copied from Electrical UIGs
RELAY INSPECTION









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Condition Code Procedure
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Housing broken .......... A ............ Require replacement.
Housing cracked ......... 2 ............ Suggest replacement.
Inoperative ( 1) ......... A ............ Require replacement.
Missing ................. C ............ Require replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned,
affecting performance .. A ........... ( 2) Require repair or
replacement.

BRAK E S YSTE M
1999 D odge P ic ku p R 1500
1998-99 BRAKES
CHRY - Disc & Drum - Trucks & Vans - Except FWD
Dakota, Ram Pickup, Ram Van
DESCRIPTION & OPERATION
All models are equipped with single-piston, sliding-caliper
front disc brakes with ventilated rotors. All models utilize self-
adjusting rear drum brakes. Rear Wheel Anti-Lock (RWAL) brake system
is standard on all models. Optional 4-wheel Anti-Lock (4WAL) brake
system is available on all models.
System also includes power brake booster, dual-reservoir
master cylinder and combination valve. Combination valve consists of
metering valve and pressure differential switch.
Models with diesel engine include a gear-driven vacuum pump.
Depending on speed of engine, pump produces 8-25 in. Hg. Models
without full-floating rear axle use 9", 10" or 11" single-anchor rear
brakes. Models with full-floating rear axle use 12" or 13" single-
anchor rear brakes.
NOTE: For information on Anti-Lock Brake Systems (ABS), see
appropriate ANTI-LOCK article.
BLEEDING BRAKE SYSTEM
BLEEDING PROCEDURES
Complete Brake System
Before bleeding system, exhaust all vacuum from power unit by
depressing brake pedal several times. Bleed master cylinder using
bleeder screws (if equipped). Bleed wheel cylinders and calipers in
sequence. See BLEEDING SEQUENCE table.
BLEEDING SEQUENCE









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Application Sequence
1999 Dakota & Ram Van .......... Master Cylinder, Combination Valve,
RR, LR, RF & LF
All Other Models ............... Master Cylinder, Combination Valve,
Rear Anti-Lock Valve, RR, LR, RF & LF









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Master Cylinder (Bench Bleeding)
1) Bench bleed master cylinder before installation. Place
master cylinder in soft-jaw vise. Install bleeder tubes in both
outlets of master cylinder. See Fig. 1.
2) Fill master cylinder with clean brake fluid. Ensure ends
of bleeder tubes are submerged in brake fluid.
3) Using a wood dowel, apply and release master cylinder
until no air bubbles exist in brake fluid flow. Leave bleeder tubes
installed on master cylinder during installation. Install master
cylinder. Remove bleeder tubes, and connect brakelines. Bleed brake
system if necessary.

1) Start engine, and check booster vacuum hose connections. A
hissing noise indicates a vacuum leak. Repair any vacuum leaks before
proceeding. Stop engine, and shift transmission into Neutral. Pump
brake pedal until all vacuum reserve in booster is depleted.
2) Hold brake pedal under light pressure. If pedal does not
hold firm and falls away, master cylinder may be faulty. Bleed system
using appropriate method, and repeat step 1). See BLEEDING PROCEDURES
under BLEEDING BRAKE SYSTEM.
3) If pedal still does not hold firm, master cylinder is
faulty. If pedal holds firm, start engine and observe pedal height. If
pedal height change is not apparent, power booster or vacuum check
valve is faulty. Install good check valve, and repeat steps 1) and 2).\
If pedal falls away slightly under light pressure and then holds firm,
go to next step .
4) Start engine. Release brake pedal. Increase engine speed
to 1500 RPM. Close throttle and immediately turn off ignition. Wait at
least 90 seconds, and try brake action again. Booster should provide 2
or more vacuum assisted pedal applications. If vacuum assist is not
provided, perform booster and check valve vacuum tests.
POWER BRAKE BOOSTER VACUUM TEST
Connect vacuum gauge to booster check valve using "T"
fitting. Start engine, and run at idle speed for one minute. Clamp
hose shut between vacuum source and check valve. Stop engine, and
observe vacuum gauge. If vacuum drops more than one in. Hg within 15
seconds, booster diaphragm or check valve is faulty.
POWER BRAKE BOOSTER CHECK VALVE TEST
Disconnect vacuum hose from check valve. Remove check valve
and valve seal from booster. Use a hand-operated vacuum pump for
testing. Apply 15-20 in. Hg at large end of check valve. Vacuum should
hold steady. If gauge on pump indicates vacuum loss, check valve is
faulty and should be replaced.
COMBINATION VALVE METERING VALVE TEST
Metering valve operation can be checked visually with aid of
an assistant. While an assistant applies and releases brake pedal,
observe metering valve stem. If valve is operating correctly, stem
will extend slightly when brakes are applied, and contract when brakes
are released. If valve is faulty, replace combination valve assembly.
COMBINATION VALVE PRESSURE DIFFERENTIAL SWITCH TEST
1) Using an assistant, apply brake pedal. Observe brake
warning light. Raise and support vehicle, and connect a bleed hose to
one rear wheel cylinder. Submerge other end of hose into container
partially filled with brake fluid. Have assistant press and hold brake
pedal down while observing brake warning light. Open bleeder screw. If
warning light glows, switch is operating properly.
2) If warning light fails to glow, check circuit fuse, bulb
and wiring. Repair as necessary. Repeat step 1). If warning light
fails to glow, check brakelight, parking brake switches and related
wiring. Repair as necessary. Repeat step 1). If warning light fails to
glow, pressure differential switch is faulty. Replace combination
valve assembly, and bleed brake system. Verify proper valve operation.
REMOVAL & INSTALLATION


DRIV E A XLE - F B I S EM I- F LO ATIN G
1999 D odge P ic ku p R 1500
1998-99 DRIVE AXLES
CHRY - FBI Semi-Floating Axles
Ram Pickup
IDENTIFICATION
DRIVE AXLE APPLICATION








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Application Axle Ring Axle
Model Gear Size Ratio
Front Axle ........ 216 FBI ......... 8.50" .. 3.54, 3.92 & 4.09
Front Axle ........ 248 FBI ......... 9.75" ........ 3.54 & 4.10









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DESCRIPTION & OPERATION
The Front Beam-Design Iron (FBI) axles is of an iron center
casting (differential housing) with axle shaft tubes extending from
both sides. The tubes are pressed in to form a one-piece axle housing
and is a semi-floating design.
Axle contains an integral carrier with hypoid-type ring gear
and pinion with semi-floating axle shafts. Load is supported by hub
bearings. Axle shafts are retained by nuts at the hub bearings. Hub
bearings are bolted to steering knuckle at outboard end of axle tube
yoke. Hub bearings are serviced as an assembly. On vehicles equipped
with Anti-Lock (ABS) brakes, a brake sensor is mounted on knuckle
assemblies, and tone rings are pressed onto axle shaft.
Differential is a one-piece design and differential pinion
mate shaft is retained with a roll pin. Differential bearing preload
and ring gear backlash is adjusted by use of shims, and pinion bearing
preload is set and maintained by use of a collapsible spacer.
Axle shaft is engaged or disengaged by an axle vacuum shift
motor. Vacuum shift motor is operated by engine vacuum and is
controlled by a switch mounted on transfer case.
AXLE RATIO & IDENTIFICATION
NOTE: Axle ratio can be identified by axle identification tag
attached to axle housing cover. See IDENTIFICATION.
LUBRICATION
CAPACITY
DRIVE AXLE CAPACITY ( 1)








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Application Pts. (L)\
216 FBI .................................................. 4.8 (2.3)\
248 FBI .................................................. 7.6 (3.6)\
(1) - Approximate drive axle capacity listed. Lubricant level should
be 1/2" below oil filler hole in axle housing cover.









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FLUID TYPE
Use SAE 80W-90 or 90W hypoid gear lubricant with MIL-L-2105-C
and API GL-5 ratings.
TROUBLE SHOOTING
NOTE: See appropriate table in TROUBLE SHOOTING article in GENERAL
INFORMATION.
REMOVAL & INSTALLATION
AXLE SHAFT & HUB BEARING
Removal
1) Raise and support vehicle. Remove wheel. Remove brake
caliper with hose attached, and secure aside. DO NOT allow brake
caliper to hang by brake hose. Remove brake rotor. Remove ABS wheel
speed sensor (if equipped). Remove grease cap from center of front
hub. Remove cotter pin from end of axle shaft. Remove axle nut and
washer.
2) Remove hub/bearing assembly-to-knuckle bolts. Remove
hub/bearing assembly from steering knuckle and axle shaft. Remove
brake dust shield. To remove right (passenger-side) axle shaft,
carefully pull axle shaft from axle housing.
NOTE: Left axle shaft will disengage from collar located on
intermediate axle shaft.
3) To remove left (driver's side) axle shaft, disconnect
electrical connector and vacuum hoses at vacuum shift motor. Remove
bolts, vacuum shift motor and gasket. Carefully pull axle shaft from
axle housing and collar on intermediate axle shaft.
Installation
1) Install NEW oil seal on axle shaft with seal lip facing
toward splines on differential end of axle shaft. Coat seal lip with
wheel bearing grease.
2) Install right axle shaft into axle housing. Ensure axle
shaft engages with side gears in differential.
3) To install left axle shaft, ensure collar is engaged with
splines on intermediate axle shaft. Install left axle shaft into axle
housing. Ensure axle shaft engages with splines on collar. Install
vacuum shift motor, ensuring fork on vacuum shift motor engages groove
on collar. Install and tighten bolts to specification. See TORQUE
SPECIFICATIONS table.
4) To complete installation, reverse removal procedure. Apply
silicone rubber sealant to edge of grease cap before installing.
Tighten bolts/nuts to specification. See TORQUE SPECIFICATIONS table.
DRIVE SHAFT
Removal
1) Raise and support vehicle. Ensure transmission and
transfer selector levers case are in Neutral. Reference mark drive
shaft and pinion flange for reassembly reference.
2) Remove bolts and "U" joint straps at pinion flange. Remove
center carrier bearing bolts (if equipped). Remove drive shaft.
CAUTION: The "U" joint components are not serviceable. Replace
complete assembly. DO NOT reuse.

Installation
To install, reverse removal procedure using NEW "U" joint
straps and bolts. Ensure all reference marks are aligned. Tighten
bolts to specification. See TORQUE SPECIFICATIONS table.
PINION FLANGE & OIL SEAL
Removal
1) Raise and support vehicle. Reference mark drive shaft and
pinion flange on differential for reassembly. Remove bolts and "U"
joint straps at pinion flange on differential. Disconnect drive shaft
from differential, and support it aside.
2) Using INCH-lb. torque wrench, measure amount of force
required to rotate pinion. This is pinion bearing preload. Record
pinion bearing preload for reassembly reference.
3) Remove pinion nut and washer from pinion. Scribe reference
mark on pinion flange and pinion for reassembly. Using Holder (C-3281)\
and appropriate flange remover, remove pinion flange from pinion.
Remove oil seal from axle housing.
Installation
1) Ensure oil seal surface in axle housing is clean. Coat lip
of oil seal with gear lube. Using appropriate oil seal installer and
handle, install oil seal.
2) Install pinion flange on pinion with reference mark
aligned. Press pinion flange onto pinion. Install washer and pinion
nut. Tighten pinion nut while rotating pinion, ensuring bearings are
properly seated. Tighten nut until preload measured before disassembly
is achieved. DO NOT exceed maximum torque specification. See TORQUE
SPECIFICATIONS table.
3) To install remaining components, reverse removal procedure
using NEW "U" joint straps and bolts. Ensure all reference marks are
aligned. Tighten bolts to specification. See TORQUE SPECIFICATIONS
table. Check lubricant level and add if necessary.
AXLE HOUSING ASSEMBLY
NOTE: Removing axle housing assembly is not necessary unless axle
housing is damaged. Differential carrier and components can
be serviced by removing differential assembly from axle
housing.
Removal
1) Raise and support vehicle. Remove front wheels. Reference
mark drive shaft to pinion flange for reassembly. Remove bolts and "U"
joint straps at pinion flange. Remove drive shaft, and support aside.
Remove brake calipers, and support aside with wire. DO NOT allow
calipers to hang from brake hoses.
2) Disconnect ABS sensor harness connectors (if equipped).
Disconnect drag link and tie rod from steering knuckles. Disconnect
shock absorber from axle housing. Disconnect stabilizer bar links at
spring brackets.
3) Disconnect electrical connector and vacuum hoses at vacuum
shift motor. Support axle housing assembly with floor jack. Remove
bolts from upper and lower suspension arms. Lower axle housing
assembly from vehicle and remove.
Installation
To install, reverse removal procedure. Ensure reference marks
on drive shaft and pinion flange align. Tighten suspension arms with
vehicle at normal operating height. Tighten bolt/nuts to
specification. See TORQUE SPECIFICATIONS table. Check axle fluid level

and fill if necessary.
STEERING KNUCKLES
Removal & Installation
1) Raise and support vehicle. Remove hub bearing and axle
shaft. Remove tie rod or drag link end from steering knuckle arm.
Remove ABS sensor harness and bracket from steering knuckle.
2) Remove cotter pin from upper ball stud nut. Remove upper
and lower ball stud nuts. Using a brass hammer, strike steering
knuckle to remove knuckle from axle tube yokes.
3) To install, reverse removal procedure. On 216 FBI axles,
tighten lower and upper ball stud nuts to specification. See TORQUE
SPECIFICATIONS table.
4) On 248 FBI axles, tighten lower ball stud nut to
specification. DO NOT install cotter pin at this time. Install and
tighten upper ball stud nut to specification. Retorque lower ball stud
nut to specification. See TORQUE SPECIFICATIONS table.
AXLE SHIFT MOTOR
Removal & Installation
1) Disconnect vacuum and wiring connector from shift housing.
Remove indicator switch, shift motor housing cover, gasket and shield
from housing.
2) To install, reverse removal procedure. Ensure shift fork
is correctly guided into shift collar groove. Tighten mounting bolts
to 96 INCH lbs. (11 N.m). Add 5 ounces (148 ml) of GL-5 gear lubrica\
nt
to shift motor housing through indicator switch mounting hole.
DIFFERENTIAL ASSEMBLY
NOTE: Differential assembly consists of differential case and
components mounted in axle housing. For differential assembly
servicing, see DIFFERENTIAL ASSEMBLY under OVERHAUL.
OVERHAUL
DIFFERENTIAL ASSEMBLY
Disassembly
1) Remove axle shafts from differential. See AXLE SHAFT & HUB
BEARING under REMOVAL & INSTALLATION.
2) Note identification marks on bearing caps and axle housing
for reassembly reference. Bearing caps must be installed in original
location. If marks are not present, place marks on bearing caps and
axle housing.
3) Remove bolts and bearing caps. Place Axle Housing Spreader
(W-129-B) on axle housing so dowel pins engage with locating holes.
See Fig. 1 . Install hold-down clamps. Finger tighten turnbuckle on
axle housing spreader.
4) Install pilot stud and dial indicator on axle housing.
Position dial indicator so stem is resting against opposite side of
axle housing, with pressure on stem.
CAUTION: DO NOT spread axle housing more than .020" (.50 mm), or axle
housing may be damaged.
5) Adjust dial indicator to zero. Tighten turnbuckle enough
to spread axle housing for differential case removal while noting
reading on dial indicator. Dial indicator reading should not exceed .
020" (.50 mm).