Master Cylinder: Reassembly

Put check valve spring in drum brake outlet.
NOTE: Check valve in disc brake outlet will cause disc brakes to lock up.

Put check valve on top of spring and insert tube seat in outlet against valve. Use a spare tube nut, and screw nut into outlet to bottom tube seat. Remove nut and inspect for burrs or shavings caused by installing seat.

NOTE: Before assembly, dip all component parts in clean brake fluid. Assembling seals dry can damage them.

CAUTION: Polishing the piston bore on aluminum master cylinders with anything abrasive is prohibited.
Install new secondary cups on rear of front (secondary) piston. Place cup lips facing away from each other. Some front pistons use a cup in rear grooves and an "O" ring in second groove from rear. Place cup so lip faces forward and back of cup is against protector washer.
NOTE: Protector washer may be permanently attached to cup.

Fig 1: Common Reservoir Master Cylinder General Motors Manual Brake Shown
Courtesy of NOT AVAILABLE

Fig 2: Common Reservoir Master Cylinder General Motors Power Brake Shown
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If it is necessary to disassemble rear (primary) piston for replacement of parts see "Fig 4" illustration.

Fig 3: General Motors Aluminum Body Master Cylinder
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Coat bore of cylinder and all cups with brake fluid. Place spring retainer on end of front spring. Place spring on end of front piston so that retainer is seated inside cup. Hold open end of master cylinder down. Push front spring and piston up into bore until spring seats against end of cylinder.
Hold master cylinder with open end up. Insert rear piston assembly with spring end going in first. Install lock ring in groove, or screw and retainer if used. Push rear piston into bore. Install stop screw and "O" ring if used.

Fig 4: Exploded View of Typical Primary Piston Assembly
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Fig 5: Exploded View of Typical Secondary Piston Assembly
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NOTE: Stop screw is a special screw. Do not use any other type as a substitute.

CAUTION: On all Cadillac models (except Seville) a stop screw is not used even though a drilled and tapped hole may be provided. If stop screw is installed, damage to master cylinder piston or seal will result.

Fig 6: Chrysler Corp. Aluminum Body Master Cylinder
Courtesy of NOT AVAILABLE
Install master cylinder cover and gasket. Place beaded side of gasket against master cylinder. On manual brake systems, assemble pushrod through retainer if used. Push retainer over end of master cylinder. Install a new boot over pushrod and press boot down over pushrod retainer.