Power Brake Unit: Reassembly
- Place power piston on bench with push rod end up. Install assembly cone J-28458 over push rod end of piston. Lubricate inside diameter of secondary diaphragm with silicon lubricant and fit in secondary support plate.
- Install secondary diaphragm and support plate over power piston and push down until it bottoms. See Fig 1. Lubricate inside diameter of secondary power piston bearing and install in housing divider with flat surface of bearing on the same side as 6 raised lugs on divider.
- Hold divider so that formed over flange faces up. Press divider down over assembly cone and onto power piston to rest against secondary diaphragm. Lubricate inside diameter of primary diaphragm and install in primary support plate. Remove assembly cone from power piston, place primary support plate and diaphragm assembly over power piston and push down until it bottoms.
- Place diaphragm retainer over power piston and onto diaphragm. Install assembly cone J-28458 over power piston onto diaphragm retainer and strike with hammer until retainer is locked on neck of power piston. Remove assembly cone.
- Install reaction retainer, piston rod and power head silencer. Place primary power piston bearing in rear housing center hole. Lubricate with silicon lubricant on inner diameter. Attach front housing to holding fixture and place fixture in vise. Install power piston assembly to rear housing.
- Install power piston return spring over reaction retainer and lower rear housing onto front housing. Align scribe marks and press down on spanner (J-9504), turning clockwise to lock housings. Stake 2 housing tabs into sockets at 2 locations 180° apart.
- Lubricate inside and outside diameters of grommet and front housing seal. Install seal, grommet, vacuum check valve, silencer and push rod boot.
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