F 350 4WD Pickup V8-7.3L DSL (1988)
Vacuum Pump: Description and Operation
Fig. 2 Vacuum Pump Installation
On vehicles with diesel engines, vacuum available to operate the vacuum booster brake is insufficient, therefore vacuum is supplied from a vacuum
pump located on the top right side or left front side of the engine, Fig. 2. This pump is driven by a single belt off the alternator. These vehicles also
incorporate a low-vacuum switch that actuates the brake warning light when vacuum is below a specified level. This switch senses vacuum through a
fitting in the intake manifold that intercepts vacuum flow from the pump.
