Power Brake Unit Push Rod Clearance
- Clearance between power brake unit push rod and master cylinder piston (dimension "A") prevents brake drag. See Fig 1. To measure this clearance, place straightedge across master cylinder end face. Measure distance between surface of straightedge and master cylinder piston. Record dimension measured.
- Subtract thickness of straightedge from dimension obtained in step 1). This is dimension "B". Measure distance between master cylinder-to-power brake unit mating surface (on master cylinder) and master cylinder end face. This is dimension "C".
- Place straightedge across master cylinder-to-power brake unit mating surface (on power brake unit). Measure distance between straightedge and end of push rod. Record this dimension.
- Subtract thickness of straightedge from dimension recorded step 3). This is dimension "D".
- Subtract dimension "C" from dimension "B". Record difference; subtract dimension "D" from this difference. This is dimension "A". If dimension "A" is not 0-.010" (0-0.25 mm), turn adjustable end of push rod until dimension "A" is within specification.
Courtesy of CHRYSLER CORP.