F 350 2WD Pickup V8-7.3L DSL (1988)
Vacuum Brake Booster: Service and Repair
Fig. 2 Checking Reaction Disc Installation
Make sure booster rubber reaction disc is properly installed as shown in Fig. 2, if the master cylinder pushrod is removed or accidentally pulled out. A
dislodged disc may cause excessive pedal travel and extreme operation sensitivity. The disc is black compared to the silver colored valve plunger that
will be exposed after pushrod and front seal are removed. The booster unit is serviced as an assembly and must be replaced if the reaction disc cannot be
properly installed and aligned, or if it cannot be located within the unit itself.
1.
Disconnect battery ground cable.
2.
Disconnect stop lamp switch electrical connectors.
3.
Support underside of master cylinder, then remove power brake unit-to-master cylinder attaching nuts.
4.
Remove vacuum hose between manifold and power brake unit, or power brake unit check valve. Remove check valve, if equipped.
5.
Separate power brake unit and master cylinder, leaving master cylinder supported far enough away to allow removal of power brake unit.
6.
On models equipped with pushrod mounted stop lamp switch, remove retaining pin, then slide switch, pushrod, spacers and bushing off brake
pedal pin.
7.
On models equipped with brake pedal mounted stop lamp switch, remove attaching bolt, nut and plastic bushing, then disconnect power brake
unit pushrod from brake pedal.
8.
On all models, remove power brake unit attaching bolts and the power brake unit.
9.
Reverse procedure to install.
