Rear brake fluid pressure regulator: 1 - earring for fastening the elastic lever to the rear axle; 2 - elastic lever retainer in the earring; 3 - elastic lever; 4 - regulator mounting bracket; 5 - protrusion of the plate adjustment bracket; 6 - front regulator mounting bolt; 7 - plate adjustment bracket; 8 - plate; 9 - lever; 10 - regulator: 11 - control hole, closed with a plug; 12 - arrow on the regulator body indicating the direction of liquid flow in the connected tube.
The drive of the service brake system is hydraulic and consists of a brake pedal, a master brake cylinder with a vacuum booster, four working brake cylinders and a fluid pressure regulator in the rear brake mechanisms. The main brake cylinder is connected to the working cylinders of the wheel brake mechanisms by metal tubes.
The internal cavity of the main brake cylinder is divided by pistons into two separate chambers. Each chamber serves its own circuit. When the brake pedal is pressed, the pistons of the master brake cylinder begin to move, forcing fluid under pressure from the chambers into the brake pipes and then into the wheel brake cylinders. Due to the fact that the chambers of the main brake cylinder do not communicate, if one of the circuits is depressurized, the second brake circuit remains operational.
The force applied to the brake pedal is increased by a vacuum booster, which uses the vacuum created in the receiver when the engine is running. If the engine stalls while the car is moving, you will have to apply significantly more force to the brake pedal to stop the car.
The pipes leading to the rear brake cylinders pass through the pressure regulator. When braking sharply, the load on the front axle of the car increases and the load on the rear axle decreases. At the same time, the front wheels' grip on the road improves, while the rear wheels' grip worsens and they easily lock, making the car's rear axle prone to skidding. To prevent this from happening, the pressure regulator, when unloading the rear axle, limits the fluid pressure in the rear brake cylinders and prevents them from instantly locking.
The regulator body has a control hole, closed with a plug. Leakage of fluid from this hole indicates that the regulator cuffs are not tight and that it needs to be repaired or replaced.