Function of Pressure Relief Valves

Function of Pressure Relief Valves
When the vehicle is driven on poor road surfaces, the stabilizer bar movements give rise to brief vacuum pressures (cavitation) in the oscillating motors which in turn cause rattling noises.
Pressure relief valves have been fitted on the front oscillating motor in order to eliminate these noises. These pressure relief valves allow filtered air to flow into the oscillating motor through the connected pneumatic lines. This prevents cavitation.
This small quantity of air is absorbed by the hydraulic fluid (Pentosin) to form an emulsion, which is discharged during the next activations of the oscillating motor. The air is separated in the expansion tank.
Because no noises can be heard at the rear axle, the pressure relief valves have been omitted from the rear oscillating motor.