Master Cylinder Push Rod
- Before installing master cylinder, measure clearance between master cylinder piston and power brake unit push rod. Turn adjusting nut on Adjustment Gauge (49-B043-001) clockwise to fully retract gauge rod. Place adjustment gauge onto power brake unit and tighten mounting nuts to 88-138 INCH lbs. (9.9-15.6 N.m).
- Using a hand-held vacuum pump, apply 19.7 in. Hg to power brake unit. Turn adjusting gauge nut counterclockwise until gauge rod just contacts push rod end of power brake unit. Perform STEP 1. See Fig 1 .
- Lightly push on end of adjusting gauge rod to ensure it is properly seated. Verify no gap exists between adjusting nut and adjusting gauge body. Remove adjusting gauge from power brake unit without disturbing adjusting nut. Place adjusting gauge on master cylinder.NOTE: When lightly pushing on end of adjusting gauge rod in step 4), only use enough pressure to bottom rod in piston. Too much pressure may cause a false reading.
- Lightly push on end of adjusting gauge rod to ensure gauge rod is bottomed in master cylinder piston. Ensure no clearance exists between adjusting gauge body and adjusting nut (clearance "B") or between body and master cylinder (clearance "C"). Perform STEP 2. See Fig 1 .
- If clearance "B" exists, push rod is too short. If clearance "C" exists, push rod is too long. To adjust clearance "B", go to next step. To adjust clearance "C", go to step 8).NOTE: Push rod threads are specially designed so bolt becomes harder to turn past a certain point to prevent loosening of bolt. Turn bolt only within this range.
- To adjust clearance "B", lightly push on end of adjusting gauge rod. Using a feeler gauge, measure clearance between adjusting nut and adjusting gauge. Perform STEP 3. See Fig 1 .
- Using Push Rod Adjuster (49-B043-004) and Adapter (49-B043-003), turn push rod nut to lengthen power brake booster push rod an amount equal to amount measured at clearance "B" in step 6). Perform STEP 4. See Fig 1 .
- To adjust clearance "C", measure and record adjusting gauge rod height D1. Perfrom STEP 5. See Fig 1 . Turn adjusting nut until adjusting gauge body sits squarely on master cylinder.
- Turn adjusting nut only enough for body to touch adjusting gauge. Measure and record adjusting gauge height D2 of adjusting gauge rod. Perform STEP 6. See Fig 1 . Subtract D1 from D2 measurement.
- Using push rod adjuster and adapter, turn push rod nut to shorten power brake booster push rod an amount equal to difference between height D1 and D2. Perform STEP 4. See Fig 1 .