You will need: A rod with a diameter of 6-8 mm (it should not have sharp edges so as not to damage the rubber protective cap).
Before starting work, install the car on a flat horizontal platform; remove the spare wheel.
The pressure regulator prevents the rear wheels from locking before the front wheels lock. This allows you to make the most of the braking capabilities of the car and prevent possible skidding of the car.
Checking the pressure regulator must be carried out with an assistant.
Thoroughly clean the pressure regulator from dirt. Inspect the regulator, it should not leak brake fluid. Otherwise, contact the experts.
Check: the plug of the regulator should be recessed into the hole in the housing by 1-2 mm.
Insert a rod with a diameter of 6-8 mm (e.g. drill) into the hole in the regulator until it stops. Do this carefully so as not to damage the rubber protective cap.
Place a mark on the stem relative to the end face of the pressure regulator housing.
Have an assistant press the brake pedal. In this case, the rod under the action of the regulator piston should go out of the housing by 1.75-2.5 mm. If the rod does not move, then the pressure regulator is defective and must be replaced.