Disc & Drum: Description

Cherokee is equipped with standard front disc and rear drum brake system. Anti-Lock Brake System (ABS) is optional. See the ANTI-LOCK BRAKE SYSTEM article.

Floating caliper disc brake assembly uses a single piston caliper which floats on 2 bolts. As brake pedal is depressed, hydraulic pressure passes through a proportioning valve to brake caliper piston. This force is transmitted to inboard brake pad, forcing it against braking surface of rotor. Pressure then moves outer caliper housing and pad inward on caliper mounting bolts, forcing outer pad against outer braking surface of rotor.

Ventilated disc brake rotors are used at the front brakes. Cast brake drums are used at the rear brakes.

A combination valve is used. Combination valve contains a rear brake proportioning valve and a pressure differential switch. Proportioning valve is not serviceable and must be replaced if it malfunctions.

Two brake warning lights are used. A Red warning light is in circuit with pressure differential switch and parking brake switch. Red warning light will come on for 2-3 seconds during start-up as a bulb check, when parking brake is applied or when there is a pressure differential between front and rear brakes indicating a system leak. On models equipped with ABS brake system, an Amber light is used when an ABS fault occurs.

Pressure differential Red brake warning light switch is used to warn vehicle operator that one side of the hydraulic system has failed. When hydraulic pressure is equal in both front and rear systems, switch piston remains centered and does not contact terminal in switch. If one side of brake system fails, hydraulic pressure moves piston toward failed side. Shoulder of piston contacts switch terminal, grounding brake warning light. Red brake warning light will also come on when parking brake is applied.

Proportioning valve operates by restricting hydraulic pressure to rear brakes at a given ratio when system hydraulic pressure reaches a certain point. This improves front-to-rear brake balance during high speed braking, when a percentage of rear weight is transferred to front wheels. Valve reduces rear brake pressure and delays rear wheel skid. On light brake application, valve allows full hydraulic pressure to rear brakes.

Parking brake system on vehicles with rear drum brakes utilizes a cable mechanism to actuate standard rear brakes for parking or emergency service.