Brake Booster - POWERMASTER: Disassembly

Remove reservoir cover and diaphragm. Empty fluid from reservoir. Remove pressure switch and "O" ring. Remove accumulator and "O" ring. Remove pump and pressure hose assembly. Remove sump hose, clamps, tube and nut assembly and brackets.
NOTE: Use care not to scratch or otherwise damage outside diameter sealing surface at push rod end of power piston assembly and bores in Powermaster body. These are primary sealing surfaces for this unit.
Remove retainer from groove in Powermaster body. Remove boot, retainer, push rod, and power piston group by grasping and pulling push rod. Disassemble retainer and boot, push rod, socket group and piston guide from power piston assembly.
Remove "O" ring from piston guide and "O" rings from power piston assembly and piston guide. Remove reaction body group from power piston assembly. Remove reaction piston and reaction disc from reaction body group.
NOTE: DO NOT attempt further disassembly of reaction body group or power piston assembly. If damage is noted or a fault is isolated to reaction body group or power piston assembly, they are replaced as assemblies.
Disassemble primary piston assembly and secondary piston assembly by directing a small amount of compressed air into outlet port at blind end of body with other outlet port plugged. Disassemble secondary seal, spring retainer and primary seal from secondary piston. Remove spring from body bore.
Place Powermaster body in a vise, but DO NOT clamp across Powermaster body. Remove reservoir using a pry bar. Remove reservoir grommets. Remove valve seat and seal, and discard. To aid in removal, tap a screw extractor into valve seat and pull straight out. Remove poppet and spring, and discard.