Brake Booster Pushrod Clearance Adjustment

Brake Booster Pushrod Clearance Adjustment

Special Tools Required
Pushrod adjustment gauge (  07JAG-SD40100)

Vacuum gauge (  07404-5790301)
Tube joint adapter (  07410-5790501)

NOTE: Master cylinder pushrod-to-piston clearance must be checked and adjustments made, if necessary, before installing the master cylinder.

1.Set the special tool (A) on the master cylinder body (B), push in the center shaft (C) until the top (D) of it contacts the end of the secondary piston (E) by turning the adjusting nut (F).


2.Without disturbing the center shaft's position, install the special tool (A) backwards on the booster.


3.Install the master cylinder nuts (B), and tighten to the specified torque.

4.Connect the booster in-line with a vacuum gauge (C) 0-101 kPa (0-760 mmHg, 30 in.Hg) to the booster's engine vacuum supply, and maintain an engine speed that will deliver 66 kPa (500 mmHg, 20 in.Hg) vacuum.

5.With a feeler gauge (A), measure the clearance between the gauge body and the adjusting nut (B) as shown.
If the clearance between the gauge body and adjusting nut is 0.4 mm (0.02 in.), the pushrod-to-piston clearance is 0 mm. However, if the clearance between the gauge body, and adjusting nut is 0 mm, the pushrod-to-piston clearance is 0.4 mm (0.02 in.) or more. Therefore it must be adjusted and rechecked.

Clearance: 0-0.4 mm (0-0.02 in.) 


6.If the clearance is incorrect, loosen the star locknut (A) and turn the adjuster (B) in or out to adjust.
  • Adjust the clearance while the specified vacuum is applied to the booster.
  • Hold the clevis (C) while adjusting.


7.Tighten the star locknut securely.

8.Remove the special tool (D).

9.Check the pushrod length (A) as shown if the booster is removed. If the length is incorrect, loosen the pushrod locknut (B), and turn the clevis (C) in or out to adjust.


10.Install the master cylinder.