General information
All models of cars considered in this Manual are equipped with a hydraulic brake system with vacuum booster. Disc brakes are always installed on the front wheels, while the rear wheel mechanisms can have either a disc or drum design.
The dual design of the main brake cylinder (MBC) equipped with two separate reservoirs allows the hydraulic circuit to be divided into two circuits operating independently of each other. The latter means that if one of the circuits fails, the second continues to operate in the previous mode, ensuring adequate braking of the vehicle. The hydraulic circuits are arranged diagonally. Failure of any of the circuits naturally leads to a decrease in braking efficiency and is accompanied by the activation of a control lamp on the instrument panel when the foot brake pedal is depressed.
All brake mechanisms are equipped with self-regulators. At the same time, wear compensation of brake pads of disc mechanisms (front and back) is carried out automatically, whereas drum brake mechanisms are equipped with special adjustment devices, which are activated during braking, as well as when the parking brake is applied.
Anti-lock braking system (ABS) can be installed on all models zafira models without ABS both rear brake circuits are equipped with rear axle load-sensitive control valves that adjust the brake fluid pressure depending on the vehicle's load level.
Master brake cylinder (MBC)
The brake master cylinder is mounted on the brake booster servo assembly, which is secured to the rear bulkhead of the engine compartment. On top of the cylinder is a large hydraulic fluid reservoir, equipped with a plastic cover. The reservoir is secured in the cylinder using bushings and a cylindrical pin.
As mentioned above, the master cylinder has a dual design, ensuring the operation of two independent hydraulic circuits. The fluid pressure in each circuit is pumped by an individual piston inside the main cylinder.
Vacuum brake booster
The booster uses the vacuum created in the intake manifold to improve the efficiency of the brake system hydraulic drive. The vacuum booster servo is mounted on the rear bulkhead of the engine compartment.
Parking brake
The parking brake control lever is located in the passenger compartment and acts on the rear wheel brakes via a cable drive. When the lever is pulled on models equipped with rear drum brakes, the cables pull the actuator levers attached to the brake shoe assemblies in the mechanisms of both rear wheels. In this case, the shoes are spread apart, pressing against the working surface of the drums.
Precautionary measures
When servicing vehicle brake components, there are some special precautions that should be taken:
- To fill the brake system, use only the correct grade of hydraulic fluid (see Chapter Routine maintenance).
- Brake pad/shoe friction linings may contain asbestos, which is harmful to health. Avoid inhaling brake dust, and do not blow it off with compressed air. Use only special cleaning agents to clean brake components.
- Ensure that all required tolerances and tightening forces are observed. When servicing components, use only serviceable tools. If in doubt, seek help from specialists. Remember that proper functioning of the brakes is the key to traffic safety.
- At the slightest sign of malfunction of the braking system, operation of the vehicle must be suspended!
- When servicing any part of the system, proceed carefully and methodically, scrupulously maintaining cleanliness. If you are not sure of the functionality of the components, replace them as a set for both brake mechanisms of each axle. Use only spare parts from well-known manufacturers.
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