Proper adjustment of the master cylinder pushrod is necessary to ensure proper operation of the power brake system. A pushrod that is too long causes the master cylinder piston to close off the replenishing port, preventing hydraulic pressure from being released and resulting in brake drag. A pushrod that is too short causes excessive brake pedal travel and causes'groaning noises
to come from the booster when the brakes are applied.a properly adjusted pushrod that remains assembled to the booster with which it was matched during production should not require service adjustment. However if the booster master cylinder or pushrod are replaced, the pushrod might require adjustment.