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Power Brake Unit: Disassembly

  1. Scribe marks on housings for reassembly reference and remove boot, front housing seal, vacuum check valve and grommet.
  2. Attach power unit front housing to holding fixture base (J-22805-1) and clamp base in vise with power section up.
  3. Place a spanner wrench (J-9504) on studs of rear housing. Press down and turn counterclockwise to unlock housings.
    NOTE: Do not put pressure on plastic power piston extension.
  4. Remove power piston bearing, return spring and power piston group. Remove piston rod and reaction retainer.
    CAUTION: Use care not to damage power piston assembly when removing reaction disc. Reaction disc must be replaced.
  5. Use awl, ice pick or similar tool to remove reaction disc. Remove reaction piston.
  6. Grasp assembly at outside edge of diaphragm support and diaphragm. Hold pushrod down against a hard surface. Use a slight force; or impact to dislodge diaphragm retainer.
NOTE: Do not disassemble power pushrod assembly.
Fig 1: Exploded View Of Typical Delco-Moraine Single Diaphragm Power Brake Unit
G09354063Courtesy of NOT AVAILABLE
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