Master Cylinder: Reassembly
- Place residual valve spring in drum brake outlet(s) of cylinder. Position residual valve on top of spring and insert tube seat in outlet against valve. Thread a spare tube nut into outlet and tighten to bottom tube seat in bore. Remove nut and inspect for burrs or shavings caused by installing seat(s).
- Install new secondary cups on rear of front (secondary) piston, with cup lips facing away from each other. Some front pistons use a cup in rear groove and an "O" ring in the second groove from the rear, with cup lip facing the rear. Install protector washer, if equipped, over front of secondary piston and install primary cup, with lip facing forward and back of cup against protector washer.NOTE: Protector washer may be permanently attached to piston.
- Install new primary seal protector and primary seal on end of rear (primary) piston, with flat side of seal against protector, and protector against flange of piston having compensating holes. Assemble spring retainer in one end of piston and secondary piston stop in opposite end. Place spring over end of rear piston, with retainer seat inside lips of primary seal. Insert extension screw through front piston stop and primary spring retainer and tighten until bottomed.
- Coat bore of cylinder and all cups with clean brake fluid, then insert secondary piston spring retainer into secondary piston spring. Position retainer and spring over end of secondary piston until retainer seats inside lips of primary cup.
- Hold cylinder with open end up and insert front piston into cylinder bore until spring seats against end of cylinder. Insert rear piston assembly, spring end first, into master cylinder bore. Install rear piston stop and retainer. Push rear piston down in bore and install front piston stop screw and gasket.CAUTION: Stop screw is a special screw. Do not substitute with any other type.
- Position master cylinder in a vise, attach bleeding tubes to cylinder, and fill reservoirs with fluid so that ends of tubes are covered. See Illustration. Tubes attached to disc brake outlet(s) must have residual valve placed on end of tube to prevent fluid from siphoning. Stroke piston in bore several times until no air bubbles appear at ends of tubes. Remove bleeding tubes and plug outlets to prevent fluid from draining.
- Install master cylinder cover and diaphragm. On vehicles without power assist units, assemble brake pedal push rod through retainer, if used, and push retainer over end of master cylinder. Install new dust boot over push rod, and press boot down over retainer.