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 in 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.