Seville V8-273 4.5L (1989)
Brake Master Cylinder: Adjustments
Proper adjustment of the master cylinder pushrod is necessary to ensure proper operation of the power brake system. A pushrod that is too long will
cause the master cylinder piston to close off the compensating port, preventing hydraulic pressure from being released and resulting in brake drag. A
pushrod that is too short will cause excessive brake pedal travel and cause 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 serviced, the pushrod may require adjustment.
There are two methods that can be used to check for proper pushrod length and installation: the gauge method and air method. Usually, if the power
unit pushrod requires adjustment, use the power unit repair kit gauge. The gauge measures from the end of the pushrod to the power unit shell.
GAUGE METHOD
Master Cylinder Pushrod Adjustment. Delco-Moraine Type Vacuum Booster
Delco-Moraine Type
On these models, the master cylinder pushrod length is fixed and is usually only checked after the unit has been overhauled.
1.
Assemble booster unit and install pushrod, ensuring pushrod is fully seated.
2.
Position go/no go gauge furnished in repair kit over pushrod as shown in Fig. 1
3.
If pushrod height is not within limits of gauge, install service adjustable pushrod and adjust rod to obtain correct height.
4.
Install power unit and check adjustment, ensuring master cylinder compensating port is open with engine running and brake pedal released.
Fig. 2 Master Cylinder Adjustment Tool
