RAM 2500 Truck 2WD L6-359 5.9L DSL Turbo VIN D FI (1997)
Vacuum Pump: Description and Operation
GENERAL INFORMATION
The vacuum pump and the power steering pump are combined into a single assembly on diesel engine models. Both pumps are operated by a drive
gear attached to the vacuum pump shaft. The shaft gear is driven by the camshaft gear.
DESCRIPTION
The vacuum pump is a constant displacement, vane-type pump. Vacuum is generated by four vanes mounted in the pump rotor. The rotor is
located in the pump housing and is pressed onto the pump shaft. The vacuum and steering pumps are operated by a single drive gear pressed onto
the vacuum pump shaft. The drive gear is operated by the engine camshaft gear. The vacuum and power steering pump shafts are connected by a
coupling. Each pump shaft has an adapter with drive lugs that engage in the coupling. The vacuum pump rotating components are lubricated by
engine oil. Lubricating oil is supplied to the pump through an oil line at the underside of the pump housing.
SERVICE
The complete assembly must be removed in order to service either pump. However, the power steering pump can be removed and serviced
separately when necessary. The vacuum pump is not a serviceable component. If diagnosis indicates a pump malfunction, the pump must be
replaced as an assembly. Do not disassemble or attempt to repair the pump. The combined vacuum and steering pump assembly must be removed
for access to either pump. However, the vacuum pump can be removed without having to disassemble the power steering pump. If the power
steering pump requires service, simply remove the assembly and separate the two pumps.
OPERATION
Vacuum pump output is transmitted to the HVAC system through a supply hose. The hose is connected to an outlet port on the pump housing and
uses an in-line check valve to retain HVAC vacuum when vehicle is not running. Pump output ranges from a minimum of 8.5 to 25 inches vacuum.
The pump rotor and vanes are rotated by the pump drive gear. The drive gear is operated by the camshaft gear.
