Chrysler 300M Service Manual page 118

LH
HYDRAULIC/MECHANICAL (Continued)
OPERATION
OPERATION - FRONT DISC BRAKES
Two machined abutments on the steering knuckle
(Fig. 6) position and align the caliper fore-and-aft.
The guide pin bolts, sleeves, and bushings control the
side-to-side movement of the caliper.
Although there are different disc brake systems
available, they operate and are serviced in the same
manner.
A square-cut rubber piston seal is located in a
machined groove in the cylinder bore. This provides a
hydraulic seal between the piston and the cylinder
wall (Fig. 9). The piston seal is designed to pull the
piston back into the bore of the caliper when the
brake pedal is released. This, along with the brake
shoe retractor clips, maintains the proper brake shoe
to rotor clearance.
A molded rubber dust boot is installed in a groove
in the cylinder bore and the piston, keeping contam-
ination from the cylinder wall and the piston (Fig. 9).
The brake shoe lining material rides against the
brake rotors braking surface. When the brakes are
applied, the shoes apply pressure against the rotor,
thus slowing the vehicle.
As brake shoe linings wear, master cylinder reser-
voir brake fluid level will go down. If brake fluid has
been added to the reservoir, overflow may occur if the
piston is pushed back into the recessed position.
An audible wear indicator (Fig. 5) is mounted on
the outboard pad of the front disc brake assemblies.
Upon contact with the brake rotor, this indicator
emits a sound, signaling that brake shoes may need
inspection or replacement.
RED BRAKE WARNING LAMP
CONDITION
RED BRAKE WARNING
LAMP ON
POSSIBLE CAUSES
1. Parking brake lever not fully
released.
2. Parking brake warning lamp
switch on parking brake lever.
3. Brake fluid level low in reservoir.
4. Brake fluid level switch.
5. Mechanical instrument cluster
(MIC) problem.
BRAKES - BASE BRAKE SYSTEM 5 - 11
Fig. 9 Piston Seal Function for Automatic
Adjustment Of Front Brakes
1 - PISTON
2 - CYLINDER BORE
3 - PISTON SEAL BRAKE PRESSURE OFF
4 - CALIPER HOUSING
5 - DUST BOOT
6 - PISTON SEAL BRAKE PRESSURE ON
OPERATION - REAR DISC BRAKES
Rear disc brakes operate similarly to front disc
brakes. Refer to Front Disc Brakes for additional
information.
DIAGNOSIS AND TESTING - BASE BRAKE
SYSTEM
NOTE: There are three diagnosis charts following
that cover the RED BRAKE WARNING LAMP,
BRAKE NOISE and OTHER BRAKE CONDITIONS.
1. Release parking brake lever.
2. Inspect and replace switch as necessary.
3. Fill reservoir. Check entire system for
leaks. Repair or replace as required.
4. Disconnect switch wiring connector. If
lamp goes out, replace switch.
5. Refer to Chassis Diagnostic Procedures
manual.
CORRECTION