Vacuum Pump Service

Fig. 81 Vacuum pump service:

On engines equipped with gear driven type vacuum pump, do not operate engine unless vacuum pump and drive assembly are installed, as the drive gear of the vacuum pump also drives the engine lubricating oil pump.
On these engines, a vacuum pump is required to provide vacuum for accessory operation. The vacuum pump may be either gear driven or belt driven, depending on vehicle application. The gear driven pump has a drive gear located at the lower end of the shaft which meshes with a gear on the engine camshaft. This vacuum pump drive gear also drives the engine lubricating oil pump. The belt driven pump has a pulley attached to the lower end of the shaft and is driven by an accessory belt.
When servicing the vacuum pump, refer to Fig. 81 for service procedures.