1998 DODGE RAM 1500 rear main seal

normal and should not be mistaken for contam-
ination.
(a) If fluid level is abnormally low, look for evi-
dence of leaks at calipers, wheel cylinders, brake
lines, and master cylinder.
(b) If fluid appears contaminated, drain out a
sample to examine. System will have to be flushed
if fluid is separated into layers, or contains a sub-
stance other than brake fluid. The system seals
and cups will also have to be replaced after flush-
ing. Use clean brake fluid to flush the system.
(4) Check parking brake operation. Verify free
movement and full release of cables and pedal. Also
note if vehicle was being operated with parking
brake partially applied.
(5) Check brake pedal operation. Verify that pedal
does not bind and has adequate free play. If pedal
lacks free play, check pedal and power booster for
being loose or for bind condition. Do not road test
until condition is corrected.
(6) Check booster vacuum check valve and hose.
(7) If components checked appear OK, road test
the vehicle.
ROAD TESTING
(1) If complaint involved low brake pedal, pump
pedal and note if it comes back up to normal height.
(2) Check brake pedal response with transmission
in Neutral and engine running. Pedal should remain
firm under constant foot pressure.
(3) During road test, make normal and firm brake
stops in 25-40 mph range. Note faulty brake opera-
tion such as low pedal, hard pedal, fade, pedal pulsa-
tion, pull, grab, drag, noise, etc.
(4) Attempt to stop the vehicle with the parking
brake only and note grab, drag, noise, etc.
PEDAL FALLS AWAY
A brake pedal that falls away under steady foot
pressure is generally the result of a system leak or
fluid contamination. The leak point could be at a
brake line, fitting, hose, or caliper/wheel cylinder. If
leakage is severe, fluid will be evident at or around
the leaking component.
Internal leakage (seal by-pass) in the master cylin-
der caused by worn or damaged piston cups, may
also be the problem cause.
An internal leak in the ABS or RWAL system may
also be the problem with no physical evidence.
LOW PEDAL
If a low pedal is experienced, pump the pedal sev-
eral times. If the pedal comes back up worn linings,
rotors, drums, or rear brakes out of adjustment are
the most likely causes. The proper course of action isto inspect and replace all worn component and make
the proper adjustments.
SPONGY PEDAL
A spongy pedal is most often caused by air in the
system. However, thin brake drums or substandard
brake lines and hoses can also cause a spongy pedal.
The proper course of action is to bleed the system,
and replace thin drums and substandard quality
brake hoses if suspected.
HARD PEDAL OR HIGH PEDAL EFFORT
A hard pedal or high pedal effort may be due to
lining that is water soaked, contaminated, glazed, or
badly worn. The power booster or check valve or a
vacuum hose could also be faulty.
PEDAL PULSATION
Pedal pulsation is caused by components that are
loose, or beyond tolerance limits.
The primary cause of pulsation are disc brake
rotors with excessive lateral runout or thickness vari-
ation, or out of round brake drums. Other causes are
loose wheel bearings or calipers and worn, damaged
tires.
NOTE: Some pedal pulsation may be felt during
ABS activation.
BRAKE DRAG
Brake drag occurs when the lining is in constant
contact with the rotor or drum. Drag can occur at one
wheel, all wheels, fronts only, or rears only.
Drag is a product of incomplete brake shoe release.
Drag can be minor or severe enough to overheat the
linings, rotors and drums.
Minor drag will usually cause slight surface char-
ring of the lining. It can also generate hard spots in
rotors and drums from the overheat-cool down pro-
cess. In most cases, the rotors, drums, wheels and
tires are quite warm to the touch after the vehicle is
stopped.
Severe drag can char the brake lining all the way
through. It can also distort and score rotors and
drums to the point of replacement. The wheels, tires
and brake components will be extremely hot. In
severe cases, the lining may generate smoke as it
chars from overheating.
Common causes of brake drag are:
²Seized or improperly adjusted parking brake
cables.
²Loose/worn wheel bearing.
²Seized caliper or wheel cylinder piston.
²Caliper binding on corroded bushings or rusted
slide surfaces.
²Loose caliper mounting.
DRBRAKES - BASE 5 - 3
BRAKES - BASE (Continued)

rotor. At the same time, fluid pressure within the pis-
ton bore forces the caliper to slide inward on the
mounting bolts. This action brings the outboard
brake pad 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 pads 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.
25). 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 amountis just enough to maintain contact between the pis-
ton and inboard brake pad.
REMOVAL
REMOVAL - FRONT
CAUTION: Never allow the disc brake caliper to
hang from the brake hose. Damage to the brake
hose will result. Provide a suitable support to hang
the caliper securely.
(1) Install prop rod on the brake pedal to keep
pressure on the brake system.
(2) Raise and support the vehicle.
(3) Remove the tire and wheel assembly.
(4) Compress the disc brake caliper.
(5) Remove the banjo bolt and discard the copper
washer.
(6) Remove the caliper slide bolts.
(7) Remove the disc brake caliper (Fig. 26) or (Fig.
27).
REMOVAL - REAR
CAUTION: Never allow the disc brake caliper to
hang from the brake hose. Damage to the brake
hose will result. Provide a suitable support to hang
the caliper securely.
(1) Install prop rod on the brake pedal to keep
pressure on the brake system.
(2) Raise and support vehicle.
(3) Remove the wheel and tire assembly.
(4) Drain small amount of fluid from master cylin-
der brake reservoir with suction gun.
(5) Remove the brake hose banjo bolt and discard
the copper washers if replacing caliper (Fig. 28).
Fig. 24 Brake Caliper Operation
1 - CALIPER
2 - PISTON
3 - PISTON BORE
4 - SEAL
5 - INBOARD SHOE
6 - OUTBOARD SHOE
Fig. 25 Lining Wear Compensation By Piston Seal
1 - PISTON
2 - CYLINDER BORE
3 - PISTON SEAL BRAKE PRESSURE OFF
4 - CALIPER HOUSING
5 - DUST BOOT
6 - PISTON SEAL BRAKE PRESSURE ON
DRBRAKES - BASE 5 - 17
DISC BRAKE CALIPERS (Continued)

CLUTCH
TABLE OF CONTENTS
page page
CLUTCH
WARNING.............................1
DIAGNOSIS AND TESTING................1
SPECIFICATIONS........................5
CLUTCH DISC
REMOVAL.............................5
INSTALLATION..........................5
CLUTCH HOUSING
DIAGNOSIS AND TESTING................7
REMOVAL.............................9
INSTALLATION..........................9
CLUTCH RELEASE BEARING
REMOVAL.............................9
INSTALLATION.........................10
FLYWHEEL
DIAGNOSIS AND TESTING................10REMOVAL.............................11
DISASSEMBLY.........................11
ASSEMBLY............................11
INSTALLATION.........................11
PILOT BEARING
REMOVAL.............................11
INSTALLATION.........................12
LINKAGE
REMOVAL.............................12
INSTALLATION.........................12
CLUTCH PEDAL POSITION SWITCH
DESCRIPTION.........................13
OPERATION...........................13
DIAGNOSIS AND TESTING................13
CLUTCH
WARNING
WARNING: Exercise care when servicing clutch
components. Factory installed clutch discs do not
contain asbestos fibers. Dust and dirt on clutch
parts may contain asbestos fibers from aftermarket
components. Breathing excessive concentrations of
these fibers can cause serious bodily harm. Wear a
respirator during service and never clean clutch
components with compressed air or with a dry
brush. Either clean the components with water
dampened rags or use a vacuum cleaner specifi-
cally designed to remove asbestos fibers and dust.
Do not create dust by sanding a clutch discs.
Replace the disc if the friction material is damaged.
Dispose of all dust and dirt containing asbestos
fibers in sealed bags or containers. This will mini-
mize exposure to yourself and to others. Follow all
recommended safety practices prescribed by the
occupational safety and health administration
(OSHA) and the environmental safety agency (EPA),
for the handling and disposal of products contain-
ing asbestos. Failure to follow these instructions
may result in personal injury or death
DIAGNOSIS AND TESTING
Road test and inspect components to determine a
clutch problem. Road test the vehicle at normalspeeds. Shift the transmission through all gear
ranges and observe clutch action. If clutch chatters,
grabs, slips or does not release properly, remove and
inspect clutch components. If problem is noise or
hard shifting, further diagnosis may be needed to the
transmission and driveline component.
CLUTCH CONTAMINATION
Contamination is a frequent cause of clutch mal-
functions. Oil, water or clutch fluid on the clutch disc
and pressure plate surfaces will cause chatter, slip
and grab. Oil contamination indicates a leak at
either the rear main seal or transmission input shaft.
Clutch fluid leaks are usually from damaged slave
cylinder push rod seals. Heat buildup caused by slip-
page between the pressure plate, disc and flywheel
can bake the oil residue onto the components. The
glaze-like residue ranges in color from amber to
black.
Road splash contamination is dirt/water entering
the clutch housing due to loose bolts, housing cracks.
Driving through deep water puddles can force water/
road splash into the housing through such openings.
IMPROPER RELEASE OR CLUTCH ENGAGEMENT
Clutch release or engagement problems can be
caused by worn or damage clutch components.
Release problems can cause hard shifting and
noise. Look for leaks at clutch cylinders, connecting
line and loose slave cylinder bolts. Also worn/loose
release fork, pivot stud, clutch disc, pressure plate or
release bearing.
DRCLUTCH 6 - 1

CONDITION POSSIBLE CAUSES CORRECTION
Clutch disc facing contaminated with
oil, grease, or clutch fluid.1. Leak at rear main engine seal or
transmission input shaft seal.1. Replace appropriate seal.
2. Excessive amount of grease
applied to the input shaft splines.2. Remove grease and apply the
correct amount of grease.
3. Road splash, water entering
housing.3. Replace clutch disc. Clean clutch
cover and reuse if in good condition.
4. Slave cylinder leaking. 4. Replace hydraulic clutch linkage.
Clutch is running partially
disengaged.1. Release bearing sticking or
binding and does not return to the
normal running position.1. Verify failure. Replace the release
bearing and transmission front
bearing retainer as necessary.
Flywheel below minimum thickness
specification.1. Improper flywheel machining.
Flywheel has excessive taper or
excessive material removal.1. Replace flywheel.
Clutch disc, cover and/or diaphragm
spring warped or distorted.1. Rough handling. Impact bent
cover, spring, or disc.1. Replace disc or cover as
necessary.
2. Improper bolt tightening
procedure.2. Tighten clutch cover using proper
procedure.
Facing on flywheel side of disc torn,
gouged, or worn.1. Flywheel surface scored or
nicked.1. Correct surface condition if
possible. Replace flywheel and disc
as necessary.
2. Clutch disc sticking or binding on
transmission input shaft.2. Inspect components and
correct/replace as necessary.
Clutch disc facing burnt. Flywheel
and cover pressure plate surfaces
heavily glazed.1. Frequent operation under high
loads or hard acceleration
conditions.1. Correct condition of flywheel and
pressure plate surface. Replace
clutch cover and disc. Alert driver to
problem cause.
2. Driver frequently rides (slips)
clutch. Results in rapid wear and
overheating of disc and cover.2. Correct condition of flywheel and
pressure plate surface. Replace
clutch cover and disc. Alert driver to
problem cause.
Clutch disc binds on input shaft
splines.1. Clutch disc hub splines damaged
during installation.1. Clean, smooth, and lubricate hub
splines if possible. Replace disc if
necessary.
2. Input shaft splines rough,
damaged, or corroded.2. Clean, smooth, and lubricate
shaft splines if possible. Replace
input shaft if necessary.
Clutch disc rusted to flywheel and/or
pressure plate.1. Clutch not used for an extended
period of time (e.g. long term
vehicle storage).1. Sand rusted surfaces with 180
grit sanding paper. Replace clutch
cover and flywheel if necessary.
DRCLUTCH 6 - 3
CLUTCH (Continued)

The pressure cap may test properly while posi-
tioned on tool 7700 (or equivalent). It may not hold
pressure or vacuum when installed on the radiator. If
so, inspect the radiator filler neck and radiator cap's
top gasket for damage. Also inspect for dirt or distor-
tion that may prevent the cap from sealing properly.
CAUTION: Radiator pressure testing tools are very
sensitive to small air leaks which will not cause
cooling system problems. A pressure cap that does
not have a history of coolant loss should not be
replaced just because it leaks slowly when tested
with this tool. Add water to tool. Turn tool upside
down and recheck pressure cap to confirm that cap
needs replacement.
CLEANING
Use only a mild soap and water to clean the radi-
ator cap. Using any type of solvent may cause dam-
age to the seal in the radiator cap.
INSPECTION
Hold cap at eye level, right side up. The vent valve
(Fig. 42) at bottom of cap should closed. A slight
downward pull on the vent valve should open it. If
the rubber gasket has swollen and prevents vent
valve from opening, replace cap.
Hold cap at eye level, upside down. If any light can
be seen between vent valve and rubber gasket,
replace cap. A replacement cap must be the typedesigned for a coolant reserve/overflow system with a
completely sealed diaphragm spring and a rubber
gasket. This gasket is used to seal to radiator filler
neck top surface. Use of proper cap will allow coolant
return to radiator.
WATER PUMP - 3.7L/4.7L
DESCRIPTION
DESCRIPTION - WATER PUMP
A centrifugal water pump circulates coolant
through the water jackets, passages, intake manifold,
radiator core, cooling system hoses and heater core.
The pump is driven from the engine crankshaft by a
single serpentine drive belt.
The water pump impeller is pressed onto the rear
of a shaft that rotates in bearings pressed into the
housing. The housing has two small holes to allow
seepage to escape. The water pump seals are lubri-
cated by the antifreeze in the coolant mixture. No
additional lubrication is necessary.
Both heater hoses are connected to fittings on the
timing chain front cover. The water pump is also
mounted directly to the timing chain cover and is
equipped with a non serviceable integral pulley (Fig.
43).
DESCRIPTION - WATER PUMP BYPASS
The 3.7L and 4.7L engine uses an internal water/
coolant bypass system. The design uses galleries in
the timing chain cover to circulate coolant during
Fig. 41 Pressure Testing Radiator Cap - Typical
1 - PRESSURE CAP
2 - TYPICAL COOLING SYSTEM PRESSURE TESTER
Fig. 42 Radiator Pressure Cap
1 - STAINLESS-STEEL SWIVEL TOP
2 - RUBBER SEALS
3 - VENT VALVE
4 - RADIATOR TANK
5 - FILLER NECK
6 - OVERFLOW NIPPLE
7 - MAIN SPRING
8 - GASKET RETAINER
DRENGINE 7 - 59
RADIATOR PRESSURE CAP (Continued)

REMOVAL.............................38
INSTALLATION.........................38
ENGINE BLOCK
DESCRIPTION.........................38
STANDARD PROCEDURE - CYLINDER BORE
HONING............................38
CLEANING............................39
INSPECTION..........................39
CRANKSHAFT
DESCRIPTION.........................40
REMOVAL.............................40
INSPECTION..........................41
INSTALLATION.........................42
CRANKSHAFT MAIN BEARINGS
STANDARD PROCEDURE
MAIN BEARING FITTING................44
CRANKSHAFT OIL SEAL - FRONT
REMOVAL.............................46
INSTALLATION.........................46
CRANKSHAFT OIL SEAL - REAR
REMOVAL.............................47
INSTALLATION.........................47
FLEX PLATE
REMOVAL.............................48
INSTALLATION.........................48
PISTON & CONNECTING ROD
DESCRIPTION.........................48
STANDARD PROCEDURE
CONNECTING ROD BEARING FITTING....49
STANDARD PROCEDURE - PISTON FITTING..51
REMOVAL.............................51
CLEANING............................52
INSPECTION..........................52
INSTALLATION.........................52
PISTON RINGS
STANDARD PROCEDURE - PISTON RING
FITTING.............................53
VIBRATION DAMPER
REMOVAL.............................55
INSTALLATION.........................56
STRUCTURAL COVER
DESCRIPTION.........................57
OPERATION...........................57
REMOVAL.............................57
INSTALLATION.........................57
FRONT MOUNT
REMOVAL.............................58
INSTALLATION.........................59
REAR MOUNT
REMOVAL.............................61
INSTALLATION.........................61
LUBRICATION
DESCRIPTION.........................61
OPERATION...........................61
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE OIL
LEAK...............................64DIAGNOSIS AND TESTING - CHECKING
ENGINE OIL PRESSURE................65
DIAGNOSIS AND TESTING - REAR SEAL
AREA LEAKS.........................65
OIL PAN
DESCRIPTION.........................66
REMOVAL.............................66
CLEANING............................66
INSPECTION..........................66
INSTALLATION.........................66
OIL PRESSURE SENSOR/SWITCH
DESCRIPTION.........................67
OPERATION...........................67
REMOVAL.............................67
INSTALLATION.........................67
OIL PUMP
REMOVAL.............................67
DISASSEMBLY.........................68
INSPECTION..........................68
ASSEMBLY............................69
INSTALLATION.........................69
OIL FILTER
REMOVAL.............................70
INSTALLATION.........................70
OIL
STANDARD PROCEDURE - ENGINE OIL
SERVICE............................71
INTAKE MANIFOLD
DESCRIPTION.........................72
DIAGNOSIS AND TESTING - INTAKE
MANIFOLD LEAKS.....................72
REMOVAL.............................73
INSTALLATION.........................73
EXHAUST MANIFOLD
DESCRIPTION.........................74
REMOVAL.............................74
INSTALLATION.........................74
VALVE TIMING
DESCRIPTION.........................76
OPERATION...........................76
STANDARD PROCEDURE
MEASURING TIMING CHAIN WEAR.......77
SERVICE PROCEDURE - TIMING
VERIFICATION........................77
BALANCE SHAFT
REMOVAL.............................80
INSTALLATION.........................80
IDLER SHAFT
REMOVAL.............................81
INSTALLATION.........................81
TIMING BELT / CHAIN COVER(S)
REMOVAL.............................81
INSTALLATION.........................81
TIMING BELT/CHAIN AND SPROCKETS
REMOVAL.............................83
INSPECTION..........................84
INSTALLATION.........................85
9 - 2 ENGINE - 3.7LDR

for this job. In addition to deglazing, it will reduce
taper and out-of-round, as well as removing light
scuffing, scoring and scratches. Usually, a few strokes
will clean up a bore and maintain the required lim-
its.
CAUTION: DO NOT use rigid type hones to remove
cylinder wall glaze.
(2) Deglazing of the cylinder walls may be done if
the cylinder bore is straight and round. Use a cylin-
der surfacing hone, Honing Tool C-3501, equipped
with 280 grit stones (C-3501-3810). about 20-60
strokes, depending on the bore condition, will be suf-
ficient to provide a satisfactory surface. Using honing
oil C-3501-3880, or a light honing oil, available from
major oil distributors.
CAUTION: DO NOT use engine or transmission oil,
mineral spirits, or kerosene.
(3) Honing should be done by moving the hone up
and down fast enough to get a crosshatch pattern.
The hone marks should INTERSECT at 50É to 60É
for proper seating of rings (Fig. 29).
(4) A controlled hone motor speed between 200 and
300 RPM is necessary to obtain the proper cross-
hatch angle. The number of up and down strokes per
minute can be regulated to get the desired 50É to 60É
angle. Faster up and down strokes increase the cross-
hatch angle.(5) After honing, it is necessary that the block be
cleaned to remove all traces of abrasive. Use a brush
to wash parts with a solution of hot water and deter-
gent. Dry parts thoroughly. Use a clean, white, lint-
free cloth to check that the bore is clean. Oil the
bores after cleaning to prevent rusting.
CLEANING
Thoroughly clean the oil pan and engine block gas-
ket surfaces.
Use compressed air to clean out:
²The galley at the oil filter adaptor hole.
²The front and rear oil galley holes.
²The feed holes for the crankshaft main bearings.
Once the block has been completely cleaned, apply
Loctite PST pipe sealant with Teflon 592 to the
threads of the front and rear oil galley plugs. Tighten
the 1/4 inch NPT plugs to 20 N´m (177 in. lbs.)
torque. Tighten the 3/8 inch NPT plugs to 27 N´m
(240 in. lbs.) torque.
INSPECTION
(1) It is mandatory to use a dial bore gauge to
measure each cylinder bore diameter. To correctly
select the proper size piston, a cylinder bore gauge,
capable of reading in 0.003 mm (.0001 in.) INCRE-
MENTS is required. If a bore gauge is not available,
do not use an inside micrometer (Fig. 30).
Fig. 29 CYLINDER BORE CROSSHATCH PATTERN
1 - CROSSHATCH PATTERN
2 - INTERSECT ANGLE
Fig. 30 BORE GAUGE-TYPICAL
1 - FRONT
2 - BORE GAUGE
3 - CYLINDER BORE
4 - 38 MM (1.5 in)
DRENGINE - 3.7L 9 - 39
ENGINE BLOCK (Continued)

(2) Measure the inside diameter of the cylinder
bore at three levels below top of bore. Start perpen-
dicular (across or at 90 degrees) to the axis of the
crankshaft and then take two additional reading.
(3) Measure the cylinder bore diameter crosswise
to the cylinder block near the top of the bore. Repeat
the measurement near the middle of the bore, then
repeat the measurement near the bottom of the bore.
(4) Determine taper by subtracting the smaller
diameter from the larger diameter.
(5) Rotate measuring device 90É and repeat steps
above.
(6) Determine out-of-roundness by comparing the
difference between each measurement.
(7) If cylinder bore taper does not exceed 0.025
mm (0.001 inch) and out-of-roundness does not
exceed 0.025 mm (0.001 inch), the cylinder bore can
be honed. If the cylinder bore taper or out- of-round
condition exceeds these maximum limits, the cylinder
block must be replaced. A slight amount of taper
always exists in the cylinder bore after the engine
has been in use for a period of time.
CRANKSHAFT
DESCRIPTION
The crankshaft is constructed of nodular cast iron.
The crankshaft is a three throw split pin design with
six counterweights for balancing purposes. The
crankshaft is supported by four select fit main bear-
ings with the No. 2 serving as the thrust washer
location. The main journals of the crankshaft are
cross drilled to improve rod bearing lubrication. The
No. 6 counterweight has provisions for crankshaft
position sensor target wheel mounting. The select fit
main bearing markings are located on the rear side
of the target wheel (Fig. 31). The crankshaft oil seals
are one piece design. The front oil seal is retained in
the timing chain cover, and the rear seal is pressed
in to a bore formed by the cylinder block and the
bedplate assembly.
REMOVAL
NOTE: To remove the crankshaft from the engine,
the engine must be removed from the vehicle.
(1) Remove the engine(Refer to 9 - ENGINE -
REMOVAL).
(2) Remove the engine oil pump(Refer to 9 -
ENGINE/LUBRICATION/OIL PUMP - REMOVAL).CAUTION: DO NOT pry on the oil pan gasket when
removing the oil pan, The oil pan gasket is mounted
to the cylinder block in three locations and will
remain attached to block when removing oil pan.
Gasket can not be removed with oil pan.
(3) Remove the bedplate mounting bolts. Note the
location of the two stud bolts for installation.
(4) Remove the connecting rods from the crank-
shaft.
CAUTION: The bedplate to cylinder block mating
surface is a critical sealing surface. Do not pry on
or damage this surface in anyway.
NOTE: The bedplate contains the lower main bear-
ing halves. Use care when handling bedplate as not
to drop or damage bearing halves. Installing main
bearing halves in the wrong position will cause
severe damage to the crankshaft.
Fig. 31 CRANKSHAFT AND TARGET RING
1 - CRANKSHAFT
2 - CRANKSHAFT POSITION SENSOR TARGET RING
9 - 40 ENGINE - 3.7LDR
ENGINE BLOCK (Continued)