F 350 4WD Pickup V8-7.3L DSL (1988)
Hydraulic Brake Booster: Component Tests and General Diagnostics
Performance Check
1.
With engine off, depress and release brake pedal several times to deplete all hydraulic pressure from hydra-boost.
2.
Depress and hold brake pedal with light pressure, then start engine.
3.
If pedal falls slightly and then holds, hydra-boost is operating. If pedal does not fall slightly, the hydra-boost unit must be replaced.
Leak Test
Fig. 2 Hydra-Boost Unit Seal Location
1.
Thoroughly clean hydra-boost unit, hoses and hose connections.
2.
Start engine and run at idle speed, check hydra-boost unit, hoses and hose connections for leaks, Fig. 2.
3.
Apply brakes with heavy pressure and hold while checking for leaks. Do not hold brake pedal with heavy pressure for more than five seconds
at a time.
