7.7.3. Dismantling and assembly of wheel cylinders


Fig. 7-16. Wheel cylinder: 1 — a block emphasis; 2 — a protective cap; 3 — the cylinder case; 4 — the piston; 5 — a sealant; 6 — a basic cup; 7 — a spring; 8 — crackers; 9 — a persistent ring; 10 — the persistent screw; 11 — the union; And — a cut on a persistent ring

Remove protective caps of 2 (fig. 7-16), then a vypressuyta from the cylinder case pistons 4 assembled with details of the device of automatic control of a gap between brake shoes and a drum.

Fig. 7-17. Details of the wheel cylinder: 1 — the piston assembled; 2 — the cylinder case; 3 — the persistent screw; 4 — a persistent ring; 5 — crackers; 6 — a spring; 7 — a basic cup; 8 — a sealant; 9 — the piston; 10 — a protective cap

Install the piston assembled with the automatic device on special adaptation so that ledges of adaptation covered a head of the persistent screw 3 (fig. 7-17). The special screw-driver, turning the piston 9, turn out the persistent screw 3 of the piston. Remove from the screw a sealant 8 with a basic cup 7 and crackers 5. Separate a persistent ring 4 and the persistent screw 3.
Between blocks and a drum and the most wheel cylinder you make assembly of the automatic device for adjustment of a gap in the return sequence taking into account the following:
— persistent screws of pistons wrap the moment of 3,9-6,9 N · m (0,4–0,7 kgfs · l); A cut And (see fig. 7-16) on rings it has to be directed vertically up, the deviation from a vertical is allowed no more than 30 °. Such arrangement of a cut provides fuller removal of air from the drive of the brake mechanism of a wheel when pumping a brake;
— for preliminary compression of persistent rings, press pistons in the case of the cylinder by means of the special adaptation having the cylinder form with a conical internal opening;
— the effort of a press fitting of the piston in the cylinder has to be not less than 343 N (35 kgfs); at effort less than 343 N (35 kgfs) replace a persistent ring;
— at a piston press fitting in the cylinder it is necessary to sustain the sizes 4,5 – 4,8 mm and 67 mm (as much as possible) (see fig. 7-16) for free landing of the brake drum;
— before installation of details in the case of the cylinder grease them with plentifully brake fluid.
After assembly check movement of each piston in the cylinder case. They have to move easily within 1,25–1,65 mm. Establish by the last into place protective caps 2.