Adjustment (Except Diamante)

Place Push Rod Adjusting Gauge (MB991714) in master cylinder. Position gauge shaft so it contacts master cylinder piston and tighten wing bolt.
Apply a vacuum of 19.75 in. Hg (66.6 kPa) to brake booster using a hand held vacuum pump.
Rotate gauge tool so it is positioned offset from center of brake booster. See Fig 1.

Fig 1: Push Rod Adjusting Gauge Setup
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
On Galant & 2000 Eclipse, measure protruding length of pushrod. If protruding length is not .404-.415" (10.26-10.54 mm), adjust pushrod length by turning end of pushrod.
On all models, move gauge tool toward center of shaft so it contacts end of brake booster push rod. If contact is not as shown in position "A", shorten rod if position "B" is present, or lengthen rod if position "C" is present. See Fig 2.

Fig 2: Adjusting Brake Booster Push Rod Clearance

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.