Section 11-02C: Steering Pump, Power, ZF | 1996 F-Super Duty Motorhome Chassis Workshop Manual |
The ZF power steering pump (3A674) has been specially designed to supply pressurized oil to the power steering and brake hydro-boost units.
The ZF power steering pump is belt-driven by the engine's crankshaft. As the driven shaft rotates the power steering pump rotor (3D607), the slipper vanes inside the power steering pump also move. The centrifugal force and pressurized oil force the slipper vanes against the track of the cam ring. The oil passes from the two pressure chambers to the area between the rear cover and faceplate, pressing against the cam ring at operating pressure. The oil then passes through a power steering pump valve (3A561) to the pressure line.