Hydraulic system
The hydraulic system consists of two separate circuits. The master cylinder has separate reservoirs for each of the two circuits, and in the event of a fluid leak or failure of one of the circuits, the other will continue to operate.
Vacuum booster
The vacuum booster, which uses the vacuum and atmospheric pressure of the engine intake piping to provide boost to the hydraulic brake system, is mounted on the bulkhead of the engine compartment.
On E28 models, a hydraulic booster is installed. This system uses the hydraulic pressure of the steering pump to boost the braking system.
Parking brake
The parking brake is connected to the rear brakes and is actuated by a cable using a lever located on the center console. The parking brake assembly on models with rear drum brakes is a self-adjusting part of the rear drum brake assembly. On models with rear disc brakes, the parking brake is operated by a pair of brake shoes located in the center of the rear brake disc and is manually adjusted.
Brake pad wear warning system
The brake pad wear warning system is linked to a red warning light on the instrument panel that illuminates when the brake pads are worn to a condition requiring replacement. DO NOT IGNORE this signal. If you do not replace the pads soon after this light comes on, the brake discs will be damaged.
On some models, the brake pad wear warning system also includes a warning light that only comes on when the brake pedal is depressed to warn you in advance that the pads need to be replaced.
The wear sensor is attached to the brake pads. It is located on the left front wheel; Some models also have a sensor on the right rear wheel. The wear sensor is part of a closed circuit. As soon as the pads wear down to the level of contact with the sensor, the disc begins to wear out the part of the sensor that faces the disc. Thus, the wire inside the sensor is frayed and the red lamp on the instrument panel lights up.
Always check the sensor (And) when replacing pads. If you change the pads before the warning light comes on, the sensor (And) may remain intact. if the signal is already on, the sensor should be replaced.
Service
After completing any procedure that requires disassembly of any part of the brake system, always make a test drive to check the operation of the brakes before normal vehicle operation. Check the brakes on a clean, dry and level surface. Otherwise, the test results will be inaccurate.
Check the brakes at different speeds, with light and strong pressure on the brake pedal. The vehicle must stop evenly, without swerving in either direction. Avoid blocking the brakes as this leads to wheel slip, reduces braking efficiency and reduces vehicle controllability.
Tire condition, vehicle load, and front wheel alignment also affect brake performance.