Install the car on a lift or inspection ditch, clean the pressure regulator and its drive parts from dirt. External inspection makes sure that the pressure regulator and its drive parts are not damaged, there is no leakage of brake fluid, plug 24 (see fig. 107) recessed into the hole of the body by 1-2 mm, there is no play in the connection of the earring 11 (see fig. 106) with elastic lever 10 and bracket pin 15.
Ask an assistant to press the brake pedal. Piston 2 (see fig. 107) at the same time, it should move out of the housing by 1.6-2.4 mm, squeezing out the spring 7 (see fig. 106) until it stops in lever 5. The latter, overcoming the force from the elastic lever 10, will rotate relative to axis 4. Non-compliance with the listed requirements, lack of piston stroke, as well as its insufficient or excessive stroke indicate a malfunction of the regulator or its drive. In this case, repair or replace the pressure regulator, and after installing it, adjust the drive (see sect. «Pressure Regulator Actuator Adjustment»).