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Chrysler 300M, Dodge Interpid. Manual - part 27

BRAKES - BASE BRAKE
SYSTEM

DESCRIPTION - BASE BRAKES

The base brake system consists of the following

components:

• Brake pedal

• Master cylinder

• Power brake booster

• Brake tubes and hoses

• Proportioning valves (2)

• Disc brakes (front and rear)

• Brake lamp switch

• Brake fluid level switch

• Parking brake
All brakes are power assist type through the use of

a vacuum operated power brake booster.

The hydraulic brake system is diagonally split on

both the non-antilock and antilock braking systems.
This means the left front and right rear brakes are
on one hydraulic circuit from the master cylinder and
the right front and left rear are on the other.

Front disc brakes control the braking of the front

wheels; rear braking is controlled by rear disc
brakes.

Vehicles equipped with the optional antilock brake

system (ABS) (with and without traction control) use
a system designated Mark 20i. This system shares
most base brake hardware used on vehicles without
ABS. All components differing from the base brake
hardware are described in detail in the Antilock
Brake System section.

The parking brake on this vehicle is pedal-oper-

ated.

For more information on the description of any

individual base brake component, refer to that com-
ponent elsewhere in this section. For information on
the brake lamp switch, (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING

EXTERIOR/BRAKE

LAMP

SWITCH - DESCRIPTION)

OPERATION - BASE BRAKES

When a vehicle needs to be stopped, the driver

applies the brake pedal. The brake pedal pushes the
input rod of the power brake booster into the booster.
The booster uses vacuum to ease pedal effort as force
is transferred through the booster to the master cyl-
inder. The booster’s output rod pushes in the master
cylinder’s primary and secondary pistons applying
hydraulic pressure through the chassis brake tubes,
junction block, and proportioning valves to the
brakes at each tire and wheel assembly.

The pedal-operated parking brake operates in the

following manner. When applied, the parking brake

lever pulls on cables that actuate parking brake
shoes at each rear wheel.

For more information on the operation of any indi-

vidual base brake component, refer to that compo-
nent elsewhere in this section.

WARNING

WARNING: DUST AND DIRT ACCUMULATING ON
BRAKE PARTS DURING NORMAL USE MAY CON-
TAIN ASBESTOS FIBERS FROM PRODUCTION OR
AFTERMARKET

BRAKE

LININGS.

BREATHING

EXCESSIVE

CONCENTRATIONS

ASBESTOS

FIBERS CAN CAUSE SERIOUS BODILY HARM.
EXERCISE

CARE

WHEN

SERVICING

BRAKE

PARTS. DO NOT SAND OR GRIND BRAKE LINING
UNLESS EQUIPMENT USED IS DESIGNED TO CON-
TAIN THE DUST RESIDUE. DO NOT CLEAN BRAKE
PARTS

WITH

COMPRESSED AIR

BY DRY

BRUSHING. CLEANING SHOULD BE DONE BY
DAMPENING THE BRAKE COMPONENTS WITH A
FINE MIST OF WATER, THEN WIPING THE BRAKE
COMPONENTS CLEAN WITH A DAMPENED CLOTH.
DISPOSE OF CLOTH AND ALL RESIDUE CONTAIN-
ING ASBESTOS FIBERS IN AN IMPERMEABLE
CONTAINER WITH THE APPROPRIATE LABEL. FOL-
LOW PRACTICES PRESCRIBED BY THE OCCUPA-
TIONAL SAFETY AND HEALTH ADMINISTRATION
(OSHA) AND THE ENVIRONMENTAL PROTECTION
AGENCY (EPA) FOR THE HANDLING, PROCESSING,
AND DISPOSING OF DUST OR DEBRIS THAT MAY
CONTAIN ASBESTOS FIBERS.

CAUTION

CAUTION: Use only Mopar

brake fluid or an equiv-

alent from a tightly sealed container. Brake fluid
must conform to DOT 3 specifications. Do not use
petroleum-based fluid because seal damage in the
brake system will result.

CAUTION: Brake fluid will damage painted surfaces.
If brake fluid is spilled on any painted surfaces,
wash it off immediately with water.

CAUTION: Never use gasoline, kerosene, alcohol,
motor oil, transmission fluid, or any fluid containing
mineral oil to clean system components. These flu-
ids damage rubber cups and seals.

CAUTION: During service procedures, grease or
any other foreign material must be kept off the cal-
iper assembly, brake linings, brake rotor and exter-
nal surfaces of the hub.

BRAKES - BASE BRAKE SYSTEM

5 - 3

CAUTION: When handling the brake rotor and caliper,
be careful to avoid damaging the brake rotor and cal-
iper, and scratching or nicking the brake shoe lining.

CAUTION: If the vehicle is equipped with the Tire
Pressure Monitoring (TPM) System, the tire/wheel
assembly needs to be reinstalled in the same loca-
tion it is removed from or the TPM System (sen-
sors) will need to be retrained. Mark each tire/wheel
assembly indicating location, prior to its removal. If
the tire/wheel assemblies are switched, rotated or
replaced, the TPM System needs to be retrained.
(Refer to 22 - TIRES/WHEELS/TIRE PRESSURE
MONITORING/SENSOR - STANDARD PROCEDURE)

STANDARD PROCEDURE - BASE BRAKE
BLEEDING

CAUTION: Before removing the master cylinder
cover, wipe it clean to prevent dirt and other foreign
matter from dropping into the master cylinder.

CAUTION: Use only Mopar

brake fluid or an equiv-

alent from a fresh, tightly sealed container. Brake
fluid must conform to DOT 3 specifications.

NOTE: For bleeding this vehicles antilock brake
hydraulic system, Refer to Antilock Brake System
Bleeding.

NOTE: Do not pump the brake pedal at any time
while having a bleeder screw open during the
bleeding

process.

This

will

only

increase

the

amount of air in the system and make additional
bleeding necessary.

NOTE: Do not allow the master cylinder reservoir to
run out of brake fluid while bleeding the system. An
empty reservoir will allow additional air into the
brake system. Check the fluid level frequently and
add fluid as needed.

The following wheel circuit sequence for bleeding

the brake hydraulic system should be used to ensure

adequate removal of all trapped air from the brake
hydraulic system.

• Left rear wheel

• Right front wheel

• Right rear wheel

• Left front wheel
The base brake system can be bled using the pres-

sure method or the manual method. Both methods
are presented in this text.

PRESSURE BLEEDING METHOD

NOTE:

Follow

pressure

bleeder

manufacturer’s

instructions for use of pressure bleeding equip-
ment.

(1) Remove filler cap from the top of fluid reservoir

on master cylinder.

(2) Install Adapter, Special Tool 8224, in the caps

place on the reservoir (Fig. 1).

(3) Attach Bleeder Tank, Special Tool C-3496-B, or

equivalent, to Special Tool 8224. Pressurize the sys-
tem following the pressure bleeder manufacturer’s
instructions.

(4) Remove rubber dust caps from all 4 bleeder

screws.

Fig. 1 Pressure Bleeding Adapter Mounted On Fluid

Reservoir

1 - SPECIAL TOOL 8224
2 - MASTER CYLINDER FLUID RESERVOIR

5 - 4

BRAKES - BASE BRAKE SYSTEM

BRAKES - BASE BRAKE SYSTEM (Continued)

(5) Starting at the first wheel circuit as listed ear-

lier, attach a clear hose to the bleeder screw at that
wheels brake caliper or wheel cylinder and feed the
other end of hose into a clear jar containing enough
fresh brake fluid to submerge the end of the hose
(Fig. 2).

CAUTION: Open the bleeder screw at least one full
turn when instructed. Some air may be trapped in
the brake lines or valves far upstream, as far as ten
feet or more from the bleeder screw (Fig. 3). If the
bleeder screw is not opened sufficiently, fluid flow
is restricted causing a slow, weak fluid discharge.
This will NOT get all the air out. Therefore, it is
essential to open the bleeder screw at least one full
turn to allow a fast, large volume discharge of
brake fluid.

(6) Open bleeder screw (Fig. 2) at least one full

turn or more to obtain an adequate flow of brake
fluid.

(7) After 4 to 8 ounces of brake fluid has been bled

through the brake hydraulic circuit, and an air-free
flow (no bubbles) is maintained in the clear plastic
hose and jar, close the bleeder screw.

(8) Bleed the remaining wheel circuits in the same

manner until all air is removed from the brake
hydraulic system.

(9) Check brake pedal travel. If pedal travel is

excessive or has not improved, some air may still be
trapped in the hydraulic system. Rebleed the brake
system as necessary.

(10) Reinstall all 4 bleeder screw dust caps.
(11) Test drive vehicle to ensure brakes are operat-

ing properly and pedal feel is correct.

MANUAL BLEEDING METHOD

NOTE: To bleed the base brake system manually, an
assistants help is required.

(1) Remove rubber duct caps from all 4 bleeder

screws.

(2) Attach a clear hose to the bleeder screw at one

wheel and feed the other end of the hose into a clear
jar containing fresh brake fluid (Fig. 2).

(3) Have an assistant pump the brake pedal three

or four times and hold it down before the bleeder
screw is opened.

(4) While the pedal is being held down, open the

bleeder screw at least 1 full turn. When the bleeder
screw opens the brake pedal will drop all the way to
the floor. Continue to hold the pedal all the way
down.

(5) Once the brake pedal has dropped, close the

bleeder screw. The pedal can then be released.

(6) Repeat steps (1) through (5) until all trapped air

is removed from that wheel circuit (usually four or five
times). This should pass a sufficient amount of fluid to
expel all the trapped air from the brakes hydraulic sys-
tem. Be sure to monitor brake fluid level in master cyl-
inder fluid reservoir, to ensure it stays at a proper level.
This will ensure air does not reenter brake hydraulic
system through master cylinder.

Fig. 2 Proper Method for Purging Air From Brake

1 - CLEAR HOSE
2 - BRAKE CALIPER
3 - BLEEDER SCREW
4 - CLEAN BRAKE FLUID

Fig. 3 Trapped Air in Brake Line

1 - TRAPPED AIR

BRAKES - BASE BRAKE SYSTEM

5 - 5

BRAKES - BASE BRAKE SYSTEM (Continued)

NOTE: Monitor the brake fluid level in the fluid res-
ervoir periodically to make sure it does not go too
low. This will ensure that air does not reenter the
brake hydraulic system.

(7) Bleed the remaining wheel circuits in the same

manner until all air is removed from the brake
hydraulic system.

(8) Check brake pedal travel. If pedal travel is

excessive or has not improved, some air may still be
trapped in the hydraulic system. Rebleed the brake
system as necessary.

(9) Reinstall all 4 bleeder screw dust caps.
(10) Test drive vehicle to ensure brakes are oper-

ating properly and pedal feel is correct.

SPECIFICATIONS

BRAKE COMPONENTS

DESCRIPTION

SPECIFICATION

Brake Hydraulic System

Dual Circuit - Diagonally

Split

Brake Pedal Ratio

3.44:1

Brake Tube Fitting Type

ISO Flares

Master Cylinder Type -
with ABS

Center Valve (Port)

Master Cylinder Type -
without ABS

Vent Port

Master Cylinder
Bore/Stroke

23.8 mm x 39.4 mm
(0.937 in. x 1.55 in.)

Master Cylinder Split

50/50

Master Cylinder Outlet
Port Primary Tube Nut
Thread

M-12

Master Cylinder Outlet
Port Secondary Tube Nut
Thread - W/ABS

M-10

Master Cylinder Outlet
Port Secondary Tube Nut
Thread - W/O ABS

M-12

Power Brake Booster
Type

205 mm Vacuum Assist

Power Brake Booster
Boost

4690 At 20 inches

Manifold Vacuum

BRAKE FASTENER TORQUE

DESCRIPTION

N·m

Ft.

Lbs.

In.

Lbs.

Brake Hose Intermediate
Bracket Bolt

—

105

Caliper Banjo Bolt

—

Caliper Bleeder Screw

—

125

Caliper Guide Pin Bolts

192

Junction Block Support
Bracket Bolts

230

Master Cylinder Mounting
Nuts

250

Parking Brake Lever
Mounting Bolts

250

Power Brake Booster
Mounting Nuts

250

Tube Nuts

—

145

Wheel Mounting (Lug) Nuts

135

100

—

5 - 6

BRAKES - BASE BRAKE SYSTEM

BRAKES - BASE BRAKE SYSTEM (Continued)

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