1993 DODGE TRUCK Service Repair Manual

i - 62
BRAKES

•
Isolation/Dump
Valve Cycle Times
Activation (opening/closing) of the isolation and
dump valves is continuous during antilock operation.
The valves cycle rapidly in response to speed sensor inputs and control module signal commands. Cycle
times are measured in milliseconds.
As the demand for antilock mode brake operation
is decreased, the module deactivates the hydraulic
valve components to restore normal brake operation.

ANTILOCK
SERVICE
DIAGNOSIS
GENERAL INFORMATION An antilock system malfunction will be indicated
by illumination of the amber antilock warning lamp.
The red brake warning lamp may also illuminate.
If a problem occurs, system diagnosis should begin
with a fluid level check followed by a visual exami­
nation of the system electrical and hydraulic connec­

tions.
If obvious defects (low fluid, leaks, loose connections, etc.) are not evident, road test the vehi­

cle.
A road test should help determine if a malfunc­
tion is actually related to an antilock component.
During the road test, note if other conditions are
evident such as a low pedal, pull, grab, or similar condition. Remember that brake malfunctions such as low fluid, system leaks, parking brakes partially
applied, will also affect the antilock system. The idea
is to determine if a malfunction is actually related to
an anti-lock component.
If a road test does reveal a problem, repeat the
road test with the owner driving. Make sure the owner is not riding the brake pedal, or has forgotten
to release the parking brakes. Either situation will
generate a fault and cause the antilock light to illu­
minate.

SYSTEM FAULT
CODES
The antilock control module generates flash codes
to help identify the cause of an antilock system fault. Two different control modules are used with the
1992/1993 RWAL system. A type I module is used in
some early production models. All remaining produc­
tion models are equipped with a type II module. The type I and II modules are identified by the way
fault codes 9 and 11 are processed. If the vehicle has a type I module, codes 9 and 11 are not erased when
the ignition switch is turned to Off position. If the vehicle has a type II module, codes 9 and 11 are
erased when the switch is turned to Off.
FAULT CODES WITH TYPE I CONTROL
MODULE
The microprocessor in the electronic control module
has a memory and a self test feature. The self test
feature is activated whenever the ignition switch is
turned to Accessory or Run position. If a system fault is detected, the control module il­
luminates the antilock light and stores the fault code
in memory. Fault codes are retained in memory even after turning the ignition switch to Off position.
FAULT CODES WITH TYPE II CONTROL
MODULE The microprocessor in the electronic control module
has a memory and a self test feature. The self test
feature is activated whenever the ignition switch is
turned to Accessory or Run position.
If a system fault is detected, the control module
will illuminate the antilock indicator lamp and store
fault codes 1 through 8, 10 and 12 through 15 in the
microprocessor memory. When one of these fault
codes is generated, the control module will retain the code after the ignition switch is turned to the Off po­
sition.
When fault code 9 is generated, the code only re­
mains in microprocessor memory while the ignition switch is in Run position. Turning the ignition
switch to Off position erases fault code 9. However, if
the problem still exists when the switch is turned
back to Run position, code 9 will reappear in memory after 20 seconds and the antilock light will illumi­
nate once again.
When fault code 11 is generated, the antilock light
will illuminate when vehicle speed exceeds approxi­ mately 60.35 km/h (37.5 mph). Code 11 only remains in memory while the ignition switch is in the Run
position and the fault is present.
When the cause of a fault code 11 is corrected, the
antilock light goes off. Code 11 is erased when the ig­
nition switch is turned to Off position. However, if
the problem cause still exists when the ignition switch is turned to Run position, code 11 will reap­
pear when vehicle speed exceeds approximately 60.35 km/h (37.5 mph).

FAULT
CODE
CAPACITY
The microprocessor memory will store and display
only one fault code at a time. The stored code can be
displayed by grounding the RWAL diagnostic connec­
tor.

FAULT
CODE
IDENTIFICATION
To determine what the fault code is, momentarily
ground the RWAL diagnostic connector and count
the number of times the amber antilock lamp flashes. Fault codes and typical malfunctions are out­lined in Figure 8. Note that when a fault code is gen­
erated, the red brake warning lamp will also
illuminate. The initial flash will be a long flash followed by a
number of short flashes. The long flash indicates the
beginning of the fault number sequence and the short flashes are a continuation of that sequence.

•

BRAKES
5 - 63 You must count the long flash along with the
short flashes for an accurate fault code count.

CLEARING
A
FAULT CODE
To clear a fault code, disconnect the control module
connector or disconnect the battery for a minimum of
five seconds. During system retest, wait 30 seconds
to be sure the fault code does not reappear.

FAULT
CODE

NUMBER
TYPICAL
FAILURE
DETECTED

1
Not used.
2
Open
isolation valve wiring
or
bad control
module.

3
Open
dump valve wiring
or
bad control
module.
4
Closed
RWAL
valve switch.

5
Over 16 dump pulses generated
in
2WD
vehicles (disabled
for
4WD).
6 Erratic speed sensor reading while rolling.
7 Electronic control module fuse
pellet
open,
isolation output
missing,
or
valve wiring
shorted to ground.
8
Dump
output
missing
or
valve wiring shorted
to

ground.

9
Speed
sensor wiring/resistance (usually high
reading).
10
Sensor
wiring/resistance (usually
low
reading).

11
Brake switch always on.
RWAL
light comes
on

when speed exceeds
40
mph.
12 Not used.
13 Electronic control module phase lock loop
failure.
14 Electronic control module program check
failure.
15 Electronic control module
RAM
failure.

J9005-101

Fig.
8
RWAL
System
Fault
Codes ANTILOCK COMPONENT SERVICE
GENERAL SERVICE INFORMATION
The rear wheel antilock (RWAL) components are
serviced as assemblies only. The module, hydraulic
control valve, speed sensor and exciter ring are not
repairable. These components must be replaced if di­ agnosis indicates a fault.

HYDRAULIC VALVE REPLACEMENT VALVE REMOVAL
(1) Raise vehicle.

(2)
Disconnect valve-to-sensor harness connector
(Fig. 9). (3) Disconnect brake lines connecting hydraulic
valve to rear brakes and to combination valve.
(4) Remove hydraulic valve attaching screws and
remove valve from frame bracket (Fig. 9).

VALVE INSTALLATION
(1) Start brake lines in hydraulic valve.

(2)
Position valve on frame bracket. (3) Install and tighten valve attaching nuts to
22-34 N-m (16-25 ft. lbs.) torque. (4) Tighten valve brake lines.
(5)
Bleed hydraulic valve and brakes. Refer to pro­
cedure in Service Adjustments section.
(6)
Lower vehicle.
J9005-112

Fig.
9
RWAL
Hydraulic
Valve
Attachment

5
- 64
BRAKES

•
Fig.
10
Checking
CHECKING SPEED SENSOR
AIR GAP (1) Remove sensor from differential.
(2) Measure and record distance from underside of
sensor flange to end of sensor pole piece (Fig. 10).
Distance should be 27.17 to 27.43 mm (1.07 to 1.08

in.).
This measurement represents dimension B.
(3) Measure distance between sensor mounting
surface of differential case and teeth at top of exciter
ring (Fig. 10). Distance should be 27.56 to 28.45 mm (1.085 to 1.12 in,). This distance represents dimen­
sion A.
(4) Subtract dimension B from dimension A to de­
termine sensor air gap which is dimension C (Fig.
10).
(5) Air gap should be minimum of 0.12 mm (0.005
in.) and a maximum of 1.27 mm (0.050 in.). (6) If air gap is not within stated limits, proceed
as follows: (a) Replace sensor if dimension B is not within
limits specified in step (2). (b) Replace exciter wheel or repair differential if
dimension A is not within limits specified in step
(3).
(c) Replace sensor and exciter wheel if both com­
ponents are out of tolerance.

SPEED
SENSOR REPLACEMENT
SENSOR
REMOVAL
(1) Raise vehicle on hoist.
(2) Remove bolt securing sensor to differential
housing.
(3) Remove sensor shield and sensor from differen­
tial housing. (4) Disconnect sensor wiring and remove sensor.

SENSOR
INSTALLATION
(1) Connect wires to sensor. Be sure seal is se­
curely in place between sensor and wiring con­
nector. (2) Install O-ring on sensor (if removed). (3) Insert sensor in differential housing.
SENSOR
FLANGE
DIMENSION A

-
DIMENSION
B
DIMENSION C

SENSOR
POLE
PIECE
8905-34

Sensor
Air Gap (4) Install sensor shield.
(5) Install and tighten sensor attaching bolt to
19-29 Nnn (170-230 in. lbs.).
(6) Lower vehicle.

ELECTRONIC CONTROL MODULE REPLACEMENT
The RWAL control module is at the passenger side
of the vehicle. On models with A/C, the module is at­
tached to the dash panel near the defroster duct and
resistor board (Fig. 11). To remove the module, remove the attaching
screws, disconnect the module harness connector and
remove the module. After installing the new module,
tighten the module attaching screws to 2.3 N»m (21 in. lbs.) torque.
Fig.
11
Anti-Lock
Control
Module
Mounting

•

SPECIFICATIONS
BRAKES
5 - 65
Description
Torque Description
Torque
Brake Booster Mounting Nuts 25 N«m (220 in. lbs.)
Brakeline/Brake Hose Fittings: 3/8 or 7/16 13-20 Nrn
(115-175
in. lbs.) 1/2 or 9/16 15-23 N«m
(140-200
in. lbs.)
Brake Pedal Shaft Retainer Screw 4 Ntn (35 in. lbs.)
Caliper Adapter Mounting
Bolts:
D150/250
149 N«m (110 ft. lbs.)

W150/250
203 N«m (150 ft. lbs.)
D250/350
(heavy
duty)
216 Nrn (160 ft. lbs.)

W250/350
216 N»m (160 ft. lbs.)
Caliper-To-Brake Hose
Fitting
Bolt 48 N«m (35 ft. lbs.)
Caliper Retainer and Anti-Rattle Spring Screw 25 N«m (200 in. lbs.)
Caliper Retainer Screw (keylock
type)
20 N«m (15 ft. lbs.)
Master Cylinder Mounting Nuts 19-26 N«m
(170-230
in. lbs.)
RWAL
Valve Bolts/Nuts
22-34
Nrn
(16-25
ft. lbs.)
Rear Brake Support Plate

Bolts/Nuts:

7/16 101 N»m (75 ft. lbs.)
1/2 115 N«m (85 ft. lbs.)
Rear Brake Support Plate Retainer Nut:
8-3/8
axle
44 N«m (33 ft. lbs.)
9-1/4
axle
47 N-m (35 ft. lbs.) model
60/70
axle
115 N-m (85 ft. lbs.)

Wheel
Cylinder Mounting Bolts 15-25 N«m
(130-230
in. lbs.)

Wheel
Lug Nuts: 8-3/8
axle
142 N»m (105 ft. lbs.)
9-1/4
axle
142 Nrn (105 ft. lbs.) model
60/70
axle
coned nut 281 N«m (200 ft. lbs.)
model
60/70
flanged
5/8-18
nut. . 441 Nrn (325 ft. lbs.)
model
60/70
flanged 1-1/8 nut . . 644 Nrn (475 ft. lbs.)
J9205-44

TORQUE
SPECIFICATIONS

CLUTCH
6 - 1

CLUTCH

CONTENTS
page

CLUTCH
DIAGNOSIS
2

CLUTCH
COMPONENTS

MECHANICAL COMPONENTS
The clutch mechanism
in
AD
models with
a gas or

diesel engine consists
of a
single, dry-type clutch disc and
a
diaphragm style clutch cover.
A
hydraulic
linkage
is
used
to
engage/disengage
the
clutch disc
and cover.
The transmission input shaft
is
supported
in the

crankshaft
by a
bearing.
A
sleeve type release bear­
ing
is
used
to
operate
the
clutch cover pressure plate.
The release bearing
is
operated
by a
release fork
in

the clutch housing.
The
fork pivots
on a
ball stud
mounted inside
the
housing.
The
release fork
is
actu­ ated
by a
hydraulic slave cylinder mounted
in the

housing.
The
slave cylinder
is
operated
by a
clutch master cylinder mounted
on the
dash panel.
The
cyl­
inder push
rod is
connected
to the
clutch pedal.
The clutch disc
has
cushion springs
in the
disc
hub.

The clutch disc facing
is
riveted
to the hub. The
fac­ ing
is
made from
a
non-asbestos material.
The
clutch
cover pressure plate
is a
diaphragm type with
a one-

piece spring
and
multiple release fingers.
The
pres­ sure plate release fingers
are
preset during
manufacture
and are not
adjustable.
A
265 mm
clutch disc
and
cover
are
used
in
models
with
a 3.9L
engine.
A 280 mm
clutch disc
and
cover are used
in
models with
a 5.2L, or
5.9L engine.
A
330 mm
clutch disc
and
cover
are
used
in
models
equipped with
the
optional
5.9L
Cummins diesel
en­

gine.
Some diesel models
are
also equipped with
a

clutch pedal interlock switch.
The
switch
is in
circuit
with
the
starter relay
and is
actuated
by the
clutch
pedal
and
push
rod. The
clutch pedal must
be
fully depressed
in
order
to
start
the
engine.

HYDRAULIC LINKAGE COMPONENTS
The hydraulic linkage consists
of a
remote reser­
voir, clutch master cylinder, clutch slave cylinder and interconnecting fluid lines.
The clutch master cylinder
is
connected
to the

clutch pedal
and the
slave cylinder
is
connected
to

the clutch release fork.
The
master cylinder
is
mounted
on the
drivers' side
of the
dash panel adja­
cent
to the
brake master cylinder.
page

CLUTCH
SERVICE
11

CLUTCH LINKAGE FLUID
The clutch fluid reservoir, master cylinder, slave
cylinder
and
fluid lines
are
prefilled with fluid
at the

factory during assembly operations. The hydraulic system should
not
require additional
fluid under normal circumstances.
In
fact,
the
reser­
voir fluid level will actually increase
as
normal clutch wear occurs.
For
this reason,
it is
impor­
tant
to
avoid overfilling,
or
removing fluid from
the reservoir. If inspection
or
diagnosis indicates additional fluid
may
be
needed,
use
Mopar brake fluid,
or an
equiv­
alent meeting
SAE and DOT
standards J1703
and

DOT
3. Do not use any
other type
of
fluid.

CLUTCH
COMPONENT LUBRICATION
Proper clutch component lubrication
is
important
to satisfactory operation.
The
correct lubricant
and
not overlubricating
are
equally important. Apply rec­
ommended lubricant sparingly
to
avoid disc
and
pres­ sure plate contamination. Clutch
and
transmission components requiring
lu­

brication
are:
• pilot bearing
• release lever pivot ball stud
• release lever contact surfaces
• clutch disc
hub
splines
• clutch pedal pivot shaft bore
• clutch pedal bushings
• input shaft splines
• input shaft pilot
hub

• transmission front bearing retainer slide surface Do
not
apply grease
to any
part
of the
clutch
cover,
or
disc.

RECOMMENDED LUBRICANTS
Use Mopar multi-purpose grease
for the
clutch
pedal bushings
and
pivot shaft.
Use
Mopar high tem­
perature grease
(or
equivalent)
for all
other lubrica­
tion requirements. Apply recommended amounts
and
do
not
over lubricate.

6
- 2
CLUTCH

•
CLUTCH DIAGNOSIS
INDEX

page

Clutch Problem
Causes
, 2
General
Diagnosis
Information
2

GENERAL
DIAGNOSIS INFORMATION
Unless the cause of a clutch problem is obvious, a
road test and component inspection will be required
for accurate diagnosis. A road test will help determine the type of fault
while component inspection will identify the problem component. During a road test, drive the vehicle at normal
speeds. Shift the transmission through all gear
ranges and observe clutch action. If chatter, grab, slip, or improper release is experi­
enced, remove and inspect the clutch components.
However, if the problem is noise or hard shifting,
further diagnosis is needed. The transmission or an­
other driveline component may actually be at fault. Careful observation during a road test will help
narrow the problem area.

CLUTCH PROBLEM
CAUSES
CONTAMINATION Fluid contamination is one of the more common
causes of clutch malfunctions. Oil, water, or clutch
fluid on the clutch contact surfaces will result in
faulty operation. The usual result is chatter, slip, or
grab.

During inspection, note if any components are con­
taminated with oil, hydraulic fluid, or water/road splash.
Oil contamination indicates a leak at either the
rear main seal or transmission input shaft.
Oil leakage produces a residue of oil on the hous­
ing interior and on the clutch cover and flywheel.
Heat buildup caused by slippage between the cover,
disc and flywheel, can sometimes bake the oil residue
onto the components. The glaze-like residue ranges
in color from amber to black.
Road splash contamination means dirt and water
are entering the clutch housing due to loose bolts,
housing cracks, vent openings, or through the slave
cylinder opening. Driving through deep water pud­
dles can force water/road splash into the housing
through such openings.
An additional problem caused by water contamina­
tion and especially by steam cleaning, involves
clutch disc sticking and poor release. Water and steam vapors can be absorbed by the
clutch facing material. If the vehicle sits idle for long
page

Inspection
and
Diagnosis
Charts 5
periods after water contamination, the force exerted
by the pressure plate may cause the disc to bond it­ self to the flywheel or pressure plate.
Frequently, the only remedy for the above condi­
tion is component replacement. To avoid this prob­
lem, a vehicle should be driven as soon as possible to
heat and dry the clutch components.
Clutch fluid leaks are from a loose or damaged
slave cylinder line or connection. However, clutch
fluid leaks will usually be noted and corrected before severe contamination occurs.

CLUTCH MISALIGNMENT
Clutch components must be in proper alignment
with the crankshaft and transmission input shaft.
Misalignment caused by excessive runout or warpage of any clutch component will cause grab, chatter and improper clutch release.
Flywheel
Runout
Common causes of runout are heat warping, im­
proper machining, mounting the flywheel on a dirty crankshaft flange, incorrect bolt tightening, or im­
proper seating on the crankshaft flange shoulder.
Very light scratches or surface roughness on the
flywheel face can be cleaned up by scuff sanding with 180 grit emery cloth. However, if the surface is
warped or severely scored, replace the flywheel.
Do not machine the flywheel. The flywheel
face is manufactured with a unique surface con­
tour. Machining would negate this feature and could result in unsatisfactory operation.
Clean the crankshaft flange before mounting the
flywheel. Dirt and grease on the flange surface may cock the flywheel causing runout.
Use new bolts when remounting a flywheel and se­
cure the bolts with Mopar Lock And Seal, or Loctite

242.
Tighten flywheel bolts to specified torque only.
Overtightening could distort the flywheel hub caus­
ing runout.

Clutch
Cover
And Disc
Runout
Check the clutch disc before installation. Axial
(face) runout of a new disc should not exceed 0.5 mm
(0.020 in.). Measure runout about 6 mm (1/4 in.)
from the outer edge of the disc facing. Obtain an­ other disc if runout is excessive.

•

CLUTCH
6 - 3 Check condition of the clutch before installation. A
warped cover or diaphragm spring will cause grab and incomplete release or engagement.
Be careful when handling the cover and disc. Im­
pact can distort the cover, diaphragm spring, release
fingers and the hub of the clutch disc.
Use an alignment tool when positioning the disc on
the flywheel. The tool prevents accidental misalign­ ment which could result in cover distortion and disc
damage.
A frequent cause of clutch cover distortion (and
consequent misalignment) is improper bolt tighten­
ing. To avoid warping the cover, tighten the bolts al­
ternately (in a diagonal pattern) and evenly (2-3
threads at a time) to specified torque.
Clutch
Housing
Misalignment And Runout Clutch housing alignment is important to proper
operation. The housing bore maintains alignment be­
tween the crankshaft and transmission input shaft.
Misalignment can cause noise, incomplete clutch
release and chatter. It can also result in premature
wear of the pilot bearing, cover release fingers and
clutch disc. In severe cases, misalignment can also cause premature wear of the transmission input
shaft and bearing.
Housing face misalignment is generally caused by
incorrect seating on the engine or transmission, loose
housing bolts, missing alignment dowels or housing damage. Infrequently, misalignment may also be
caused by housing mounting surfaces that are not
parallel. If housing misalignment is suspected, housing bore
and face runout can be checked with a dial indicator
as described in the following two procedures:

MEASURING
CLUTCH HOUSING BORE
RUNOUT
(1) Remove the clutch housing and strut.
(2) Remove the clutch cover and disc.
(3) Replace one of the flywheel bolts with a 7/16-20
threaded rod that is 10 in. (25.4 cm) long (Fig. 1).
The rod will be used to mount the dial indicator.
(4) Remove the release fork from the clutch hous­
ing. (5) Reinstall the clutch housing. Tighten the hous­
ing bolts nearest the alignment dowels first. (6) Mount the dial indicator on the threaded rod
and position the indicator plunger on the surface of
the clutch housing bore (Fig. 2).
(7) Rotate the crankshaft until the indicator
plunger is at the top center of the housing bore. Zero the indicator at this point.
(8) Rotate the crankshaft and record the indicator
readings at eight points (45° apart) around the bore (Fig. 3). Repeat the measurement at least twice for
accuracy. (9) Subtract each reading from the one 180° oppo­
site to determine magnitude and direction of runout.
Refer to Figure 3 and following example.
Bore runout example: 0.000 - (-0.007) = 0.007 in. + 0.002 - (-0.010) = 0.012 in.
+ 0.004 - (-0.005) = 0.009 in.
-0.001 -
(
+ 0.001) = -0.002 in. (= 0.002 inch)
In the above example, the largest difference is
0.012 in. and is called the total indicator reading
(TIR).
This means that the housing bore is offset
from the crankshaft centerline by 0.006 in. (which is 1/2 of 0.012 in.).
On gas engines, the acceptable maximum TIR for
housing bore runout is 0.010 inch. If measured TIR is more than 0.010 in. (as in the example), bore runout
will have to be corrected with offset dowels. Offset dowels are available in 0.007, 0.014 and 0.021 in.
sizes for this purpose (Fig. 4). Refer to Correcting
Housing Bore Runout for dowel installation.
On diesel engines, the acceptable maximum
TIR for housing bore runout is 0.015 inch. How­
ever, unlike gas engines, offset dowels are not available to correct runout on diesel engines. If
bore runout exceeds the stated maximum on a diesel engine, it may be necessary to replace ei­
ther the clutch housing, or transmission adapter
plate.

CORRECTING CLUTCH HOUSING BORE
RUNOUT
(GAS
ENGINE
ONLY)
On gas engine vehicles, clutch housing bore runout
is corrected with offset dowels. However, if bore
runout exceeds 0.015 in. TIR on a diesel equipped model, the clutch housing, or transmission adapter
plate may have to be replaced. Offset dowels are not available for diesel models.
The dial indicator reads positive when the plunger
moves inward (toward indicator) and negative when it moves outward (away from indicator). As a result,
the lowest or most negative reading determines the
direction of housing bore offset (runout).
In the sample readings shown in Figure 3 and in
step (7) above, the bore is offset toward the 0.010
inch reading. To correct this, remove the housing and
original dowels. Then install the new offset dowels in
the direction needed to center the bore with the crankshaft centerline.
In the example, TIR was 0.012 inch. The dowels
needed for correction would have an offset of 0.007
in. (Fig. 4).
Install the dowels with the slotted side facing out
so they can be turned with a screwdriver. Then in­
stall the housing, remount the dial indicator and
check bore runout again. Rotate the dowels until the
TIR is less than 0.010 in. if necessary.
If a TIR of 0.053 in. or greater is encountered, it
may be necessary to replace the clutch housing.