Description & Operation
Cherokee is equipped with standard front disc and rear drum brake system. Anti-Lock Brake System (ABS) is optional. See the appropriate ANTI-LOCK 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 on the front. Cast brake drums are used on the rear.
A combination valve containing a rear brake proportioning valve and a pressure differential switch, is used. Proportioning valve is not serviceable and must be replaced if faulty. See Fig 1
Two brake warning lights may be used. A Red BRAKE warning light is in circuit with pressure differential (brake warning) switch and parking brake switch. Red BRAKE 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, an Amber ABS light is used. Amber ABS light will come on for 2-3 seconds during start-up as a bulb check and when an ABS fault occurs.
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 utilizes a cable mechanism to actuate standard rear brakes for parking or emergency service.