Speed-sensitive power steering, steering angle, function - GF46.50-P-2300SX

MODEL 216.3, 221.0 /1 up to Model Year 8

Illustration shows rotary valve / pilot bushing housing at left steer (vehicle speed 0 km/h)

Fig 1: Identifying Speed-Sensitive Power Steering, Steering Angle Function Chart

Courtesy of MERCEDES-BENZ USA

Function at vehicle speed 0 km/h

The SPS [PML] solenoid valve is energized to a maximum and as a result closed against the force of the integrated pressure spring. The pressure ratios in the reaction chambers are identical since the supply of oil is stopped. No force is applied to the reaction balls, no additional moment arises on the surfaces of the rotary valve.

Illustration shows rotary valve / pilot bushing housing at left steer (vehicle speed > 0 km/h to 100 km/h)

Fig 2: Identifying Speed-Sensitive Power Steering, Steering Angle Function Chart

Courtesy of MERCEDES-BENZ USA

The steering is light, as the steering torque applied by the driver, consisting of overcoming the force of the torsion bar, is very low. Via the constant constriction orifice the oil flow is passed on to the power steering pump reservoir virtually depressurized.

Vehicle speed > 0 km/h to 100 km/h

As the vehicle speed increases the flowing of the SPS [PML] solenoid valve decreases continuously, this is opened by the force of the integrated compression spring. The controlled pressure is lead to the reaction balls via the regulating valve which causes the pressure applied to the surfaces of the rotary valve to increase.

The force on the torsion bar is increased further as a result and the driver has to operate the steering wheel with a higher steering torque. The constant constriction orifice reduces the regulated pressure from the SPS solenoid valve. This is then passed on as an almost depressurized backflow to the power steering pump reservoir.

Illustration shows rotary valve / pilot bushing housing at left steer (vehicle speed > 100 km/h)

Fig 3: Identifying Speed-Sensitive Power Steering, Steering Angle Function Chart

Courtesy of MERCEDES-BENZ USA

Vehicle speed > 100 km/h

The SPS [PML] solenoid valve is energized to the minimum extent. As a result the highest possible pressure is led from the SPS [PML] solenoid valve to the reaction balls via the control valve which causes the pressure applied to the surface of the rotary valve to increase to a maximum.

The constant constriction orifice reduces the regulated pressure from the SPS solenoid valve. This is then passed on as an almost depressurized backflow to the power steering pump reservoir.

Steering gear of rack-and-pinion steering, component description		GF46.20-P-5137SX
Valve play compensation, rack-and-pinion steering, component description		GF46.20-P-5138SX
Steering damper of rack-and-pinion steering, component description		GF46.20-P-5139SX
Power steering pump, component description		GF46.30-P-5136SX
SPS [PML] solenoid valve, component description	Y10	GF46.50-P-5140SX