Chrysler 300M, Dodge Interpid. Manual — part 38

(8) Remove nut and screw securing transmission

control module to vehicle (Fig. 82).

(9) Lift the transmission control module (with

speed control servo attached) from its mount leaving
its wiring harness attached. Move it off to the side
toward the engine making sure not to strain the
wires and speed control servo cable.

(10) Clean any debris away from the fittings on

top of the junction block.

(11) Using the following figure, remove the chassis

brake tube leading to either the left rear or right
rear brake at the junction block (Fig. 83).

(12) If the left rear proportioning valve is suspect,

install Adapter, Special Tool 8494-3, in its place on
the junction block.

(13) If the right rear proportioning valve is sus-

pect, install Adapter, Special Tool 8494-4, in its place
on the junction block.

(14) Install

a

Pressure

Gauge,

Special

Tool

C-4007-A, to the Adapter.

(15) Tighten all tube nut fittings to 17 N·m (145

in. lbs.) torque.

(16) Bleed any air out of the system. This includes

bleeding the air from the hose between the pressure
test fitting and pressure gauge, which is done at the
pressure gauge.

(17) With the aid of a helper, apply pressure to the

brake pedal until reading on proportioning valve
inlet gauge (at master cylinder) is at the pressure
shown on the chart at the end of this procedure.
Then check the pressure reading on the proportion-
ing valve outlet gauge (at junction block outlet to
rear brake). If proportioning valve outlet pressure
does not agree with value shown on the chart (once
inlet pressure shown on chart is obtained), replace
the

junction

block

(with

internal

proportioning

valves) (Refer to 5 - BRAKES - BASE/HYDRAULIC/
MECHANICAL/JUNCTION BLOCK - REMOVAL). If
pressure is within specifications, do not replace pro-
portioning valve and perform the following steps.

(18) Remove the Pressure Gauge and Adapter,

Special Tool 8494-3 or 8494-4, from junction block.

(19) Reinstall the chassis brake tube to the junc-

tion block port. Tighten tube nut fitting to 17 N·m
(145 in. lbs.) torque.

(20) Install the transmission control module (with

speed control servo attached) in its normal position
(Fig. 82). Install the nut and screw securing it in
place.

(21) Install

the

transmission

control

module

mounting nut and screw securing it in place. Tighten
the screw to 6 N·m (45 in. lbs.). Tighten the nut to 12
N·m (107 in. lbs.) torque.

(22) Install the screw attaching the washer filler

tube to the upper radiator closure panel (Fig. 81).

(23) Install the screw attaching the speed control

servo to the upper radiator closure panel (Fig. 81).

(24) Remove the Pressure Gauge and Adapter from

master cylinder.

(25) Install the brake tube to the master cylinder

primary or secondary port. Tighten the tube nut to a
torque of 17 N·m (145 in. lbs.).

(26) Bleed the affected brake line. (Refer to 5 -

BRAKES - BASE - STANDARD PROCEDURE)

Fig. 82 Transmission Control

Module (TCM)—Removal/Installation

1 - RADIATOR UPPER SUPPORT
2 - TCM

Fig. 83 Junction Block Fitting Identification

1 - FROM MASTER CYLINDER PRIMARY
2 - FROM MASTER CYLINDER SECONDARY
3 - TO LEFT FRONT BRAKE
4 - TO RIGHT REAR BRAKE
5 - TO LEFT REAR BRAKE
6 - TO RIGHT FRONT BRAKE

LH

BRAKES - BASE BRAKE SYSTEM

5 - 47

PROPORTIONING VALVE (Continued)

(27) If no problem is found with the proportioning

valves, check the rear wheel brake shoe linings for
contamination or for replacement brake shoes not

meeting OEM brake lining material specifications.
These conditions can also cause premature rear
wheel skid.

PROPORTIONING VALVE APPLICATIONS AND PRESSURE SPECIFICATIONS

Sales Code

Brake System Type

Split Point

Slope

Identification

Inlet Pressure

Outlet Pressure

All

All Disc/Disc

400 psi

0.34

Bar Code Label

1000 psi

525-625 psi

ROTOR

DIAGNOSIS AND TESTING - BRAKE ROTOR

Any servicing of the rotor requires extreme care to

maintain the rotor within service tolerances to
ensure proper brake action.

Excessive runout or wobble in a rotor can increase

pedal travel due to piston knock-back. This increases
guide pin sleeve wear due to the tendency of the cal-
iper to follow the rotor wobble.

When diagnosing a brake noise or pulsation, the

machined disc braking surface should be checked and
inspected.

BRAKING SURFACE INSPECTION

Light braking surface scoring and wear is accept-

able. If heavy scoring or warping is evident, the rotor
must be refaced or replaced. (Refer to 5 - BRAKES -
BASE/HYDRAULIC/MECHANICAL/ROTORS

-

STANDARD PROCEDURE)

Excessive wear and scoring of the rotor can cause

improper lining contact on the rotor’s braking sur-
face. If the ridges on the rotor are not removed before
new brake shoes are installed, improper wear of the
shoes will result.

If a vehicle has not been driven for a period of

time, the rotor’s braking surface will rust in the
areas not covered by the brake shoes at that time.
Once the vehicle is driven, noise and chatter from
the disc brakes can result when the brakes are
applied.

Some discoloration or wear of the rotor surface is

normal and does not require resurfacing when lin-

ings are replaced. If cracks or burned spots are evi-
dent, the rotor must be replaced.

ROTOR MINIMUM THICKNESS

Measure rotor thickness at the center of the brake

shoe contact surface. Replace the rotor if it is worn
below minimum thickness or if machining the rotor
will cause its thickness to fall below specifications.

CAUTION: Do not machine the rotor if it will cause
the rotor to fall below minimum thickness.

Minimum thickness specifications are cast on the

rotor’s unmachined surface (Fig. 84). Limits can also
be found in the table at the end of this brake rotor
information.

Fig. 84 Minimum Thickness Markings (Typical)

1 - ROTOR MINIMUM THICKNESS MARKING
2 - ROTOR

5 - 48

BRAKES - BASE BRAKE SYSTEM

LH

PROPORTIONING VALVE (Continued)

ROTOR THICKNESS VARIATION

Thickness variation in a rotor’s braking surface

can result in pedal pulsation, chatter and surge. This
can also be caused by excessive runout in the rotor or
the hub.

Rotor thickness variation measurements should be

made in conjunction with measuring runout. Mea-
sure thickness of the brake rotor at 12 equal points
around the rotor braking surface with a micrometer
at a radius approximately 25 mm (1 inch) from edge
of rotor (Fig. 85). If thickness measurements vary by
more than 0.013 mm (0.0005 inch), the rotor should
refaced or replaced. (Refer to 5 - BRAKES - BASE/
HYDRAULIC/MECHANICAL/ROTORS

-

STAN-

DARD PROCEDURE)

ROTOR RUNOUT

On-vehicle rotor runout is the combination of the

individual runout of the hub face and the runout of
the rotor. (The hub and rotor runouts are separable).
To measure rotor runout on the vehicle, first remove
the tire and wheel assembly. Reinstall the wheel
mounting nuts on the studs, tightening the rotor to
the hub. Mount the Dial Indicator, Special Tool
C-3339, with Mounting Adaptor, Special Tool SP-
1910 on steering arm. The dial indicator plunger
should contact braking surface of rotor approximately
25 mm (one inch) from outer edge of rotor (Fig. 86).
Check lateral runout on both sides of the rotor,
marking the low and high spots on both. Runout lim-
its can be found in the table at the end of this brake
rotor information.

If runout is in excess of the specification, check the

lateral runout of the hub face. Before removing the
rotor from the hub, place a chalk mark across both
the rotor and the one wheel stud closest to where the
high runout measurement was taken. This way, the
original mounting spot of the rotor on the hub is
indexed (Fig. 87).

Remove the rotor from the hub.

Fig. 85 Checking Rotor Thickness

1 - MICROMETER

Fig. 86 Checking Rotor Runout

1 - SPECIAL TOOL SP-1910
2 - 25mm (1 INCH) FROM EDGE
3 - DISC SURFACE
4 - SPECIAL TOOL C-3339

Fig. 87 Marking Rotor and Wheel Stud

1 - CHALK MARK

LH

BRAKES - BASE BRAKE SYSTEM

5 - 49

ROTOR (Continued)

NOTE: Clean the hub face surface before checking
runout. This provides a clean surface to get an
accurate indicator reading.

Mount Dial Indicator, Special Tool C-3339, and

Mounting Adaptor, Special Tool SP-1910, to the steer-
ing knuckle. Position the indicator stem so it contacts
the hub face near the outer diameter. Care must be
taken to position stem outside of the stud circle, but
inside of the chamfer on the hub rim (Fig. 88).

Hub runout should not exceed 0.03 mm (0.0012

inch). If runout exceeds this specification, the hub
must be replaced. Refer to SUSPENSION for the hub
and bearing removal and installation procedure.

If the hub runout does not exceed this specifica-

tion, install the rotor back on the hub, aligning the
chalk marks on the rotor with a wheel mounting
stud, two studs apart from the original stud (Fig. 89).
Tighten nuts in the proper sequence and torque to
specifications.

Recheck brake rotor runout to see if the runout is

now within specifications.

If runout is not within specifications, reface or

replace the brake rotor. (Refer to 5 - BRAKES -
BASE/HYDRAULIC/MECHANICAL/ROTORS

-

STANDARD PROCEDURE)

BRAKE ROTOR LIMITS

Braking Rotor

Rotor Thickness

Minimum

Rotor

Thickness

Rotor

Thickness

Variation

Rotor Run

Out*

Rotor Micro

Finish

Front Rotor

25.87–26.13 mm

1.019 -1.029 in.

24.4 mm

0.960 in.

0.013 mm

0.0005 in.

0.08 mm

0.003 in.

15-80 RMS

Rear Rotor

11.63–12.13 mm

0.458 -0.478 in.

10.4 mm

0.409 in.

0.013 mm

0.0005 in.

0.08 mm

0.003 in.

15-80 RMS

* TIR Total Indicator Reading (Measured On Vehicle)

Fig. 88 Checking Hub Runout

1 - HUB SURFACE
2 - SPECIAL TOOL C-3339
3 - SPECIAL TOOL SP-1910

Fig. 89 Index Rotor And Wheel Stud

1 - CHALK MARK

5 - 50

BRAKES - BASE BRAKE SYSTEM

LH

ROTOR (Continued)