7.1.2. Check of efficiency of the vacuum amplifier

Fig. 7-2. Vacuum amplifier: 1 — a flange of fastening of a tip; 2 — the case of the amplifier; 3 — a rod; 4 — a cover; 5 — the piston; 6 — a bolt of fastening of the amplifier; 7 — a remote ring; 8 — a basic cup of a spring of the valve; 9 — the valve; 10 — a basic cup of the valve; 11 — a basic cup of a returnable spring; 12 — a protective cap; 13 — a holder of a protective cap; 14 — a pusher; 15 — the air filter; 16 — a returnable spring of the valve; 17 — a valve spring; 18 — a case cover sealant; 19 — a lock ring of a sealant; 20 — a persistent plate; 21 — the buffer; 22 — the valve case; 23 — a diaphragm; 24 — a returnable spring of the case of the valve; 25 — a rod sealant; 26 — a bolt of fastening of the main cylinder; 27 — a rod sealant holder; 28 — an adjusting bolt; 29 — a hose tip; 30 — valve; And — a vacuum cavity; In — the channel connecting a vacuum cavity to an internal cavity of the valve; With — the channel connecting an internal cavity of the valve to an atmospheric cavity; Е — an atmospheric cavity

Press 5–6 times a brake pedal at the idle engine to create the identical pressure close to atmospheric in cavities of A and E (fig. 7-2). At the same time determine by the effort enclosed to a pedal whether there are no jammings of the case 22 valves.
Stop a brake pedal in the middle of its course, start the engine. At the serviceable vacuum amplifier the brake pedal after start of the engine has to "leave forward".
If the pedal "does not leave forward", check fastening of a tip 29, a state and fastening of a flange 1, a hose to a tip and the union of an inlet pipe of the engine as weakening of fastening or their damage sharply reduces depression in a cavity And yes overall performance of the amplifier.
In case of spontaneous braking of the car check at the working engine the vacuum amplifier for tightness at first at the released, and then pressed motionless pedal of a brake. "Suction" of a protective cap 12 to a shaft of the case of the valve and hissing of podsasyvayemy air indicates insufficient tightness of the amplifier.
Even in the absence of "suction" of a protective cap it is recommended to check a condition of a sealant 18 for what:
— accurately remove, and then shift from an opening otbortovka on a cover the 4th protective cap 12;
— at the working engine shake in the cross direction the acting valve case shaft with effort of 29,4-39,2 N (3–4 kgfs); at the same time there should not be a characteristic hissing of the air passing in the amplifier through a sealant of the 18th cover.
At leakage of the vacuum amplifier disconnect a pusher 14 from a brake pedal, remove a protective cap 12 and put 5 g of TsIATIM-221 lubricant between a sealant and an otbortovky cover and the case of the valve, then check a condition of the air filter 15, if necessary replace it and establish into place a protective cap.
If thus it is not possible to eliminate an air suction, then it is necessary to replace the vacuum amplifier.