For consistent, optimal system pressure and high-precision power support

The FN4 power steering pump supplies exactly the right amount of oil that is needed for operating hydraulic steering systems in medium to heavy commercial vehicles.

Robust design

Proven design ensures reliable supply to the steering system

High efficiency level

with low weight


Modular assembly system

Our wide-ranging production program includes various pump designs and model series. We would also be happy to customize our solutions optimally to your individual wishes and requirements. Evamo's highly flexible modular assembly system makes most anything possible.

The FN4 can be combined in tandem with other pump types for various applications, e.g., fuel pre-feed. Both pump parts are connected via an intermediate housing and a shaft coupling.

Individual product request
The advanced product design of the TN4 commercial vehicle power steering pump enables continuous system pressure and precise power assistance.
The innovative product design of the FN4 commercial vehicle power steering pump allows connection to the air compressor or an engine power take-off.ensure energy savings for commercial vehicles.


Proven design with integrated volume flow control

The FN4 power steering pump is designed for connection to the air compressor or a power take-off on the engine. The shaft connects by means of a cross-slotted disk or spline toothing. It can be driven by either a gear or belt. For these cases, an anti-friction bearing is used for the drive shaft. The ball bearing needed for this can be integrated into the housing.

The oil reservoir can be mounted directly on the pump. This eliminates the need for the hose line and saves the manufacturer assembly costs.

The FN4 power steering pump consists of a housing with an integrated volume flow control, cover, front plate, shaft and rotor set.

The rotor set is comprised of the rotor, ten radially-guided blades as well as the cam ring with two symmetrically arranged suction and pressure zones. The fixed geometric delivery volume of the pump is defined by the design of the cam ring.

The conveyed volume flow is limited to a defined value by the integrated volume flow control. The maximum system pressure must be limited by a pressure control valve installed on the pump or in the system. If required, a pressure level of up to 200 bar is available as a special version.

Technical data

Details about
FN4 power steering pump

Details about
FN4 power steering pump
  • [1] - 
    Suction port
  • [2] - 
    Housing with flange
  • [3] - 
    Rotor with vanes
  • [4] - 
  • [5] - 
    Cam ring
  • [6] - 
    Pressure port
Delivery volume (cm³/rev) 14 17 21 25 28
Max. rotational speed (rpm) 4,500 4,500 4,500 4,000 3,500
Max. pressure (bar) 185 185 185 185 165
Controlled volumetric flow (dm³/min) 9-16 12-16 12-25 16-25 16-25
Suction port 1 1/16“ – 12UN 2B
Thread (suction port) M26 x1.5
Pressure port 3/4“ – 16UNF 2B
Thread (pressure port) M18 x1.5
Max. oil temperature (°C) 120
Weight (kg) 2.3–2.8
Drive direction of rotation clockwise or counter-clockwise