Vibration through steering wheel when stationary and turning

[DXX]

The hydraulic PS pump is a fixed displacement pump so excess pressure is bled back to the suction side of the circuit via a pressure relief valve. At low RPM this valve maybe ‘hunting’ or oscillating causing minor vibration depending on how well mounted / damped the system is designed.
Once RPM is increased the valve will almost certainly be constantly open and in constant flow so there won’t be any noticeable vibration as the pressure will be less variable.
I just changed the PS fluid on my 2001 A4 for the first time, it was a bit cloudy but clean enough for a simple hydraulic system.
I’ve already changed the PS fluid on my 2016 T6, didn’t need it but cost less than £20 and allowed me to check the oil for debris - none found.

 

[Dm85]

The hydraulic PS pump is a fixed displacement pump so excess pressure is bled back to the suction side of the circuit via a pressure relief valve. At low RPM this valve maybe ‘hunting’ or oscillating causing minor vibration depending on how well mounted / damped the system is designed.
Once RPM is increased the valve will almost certainly be constantly open and in constant flow so there won’t be any noticeable vibration as the pressure will be less variable.
I just changed the PS fluid on my 2001 A4 for the first time, it was a bit cloudy but clean enough for a simple hydraulic system.
I’ve already changed the PS fluid on my 2016 T6, didn’t need it but cost less than £20 and allowed me to check the oil for debris - none found.

I was thinking it’s probably normal to get some movement from the return hose. But just decided to get under the van and have a look at it. There are no clips just 3 rubber dampers… and it seems quite soft when pinching it. and was touching the sub frame. For a test I put some armaflex pipe insulation around it and cable tied it up away from the subframe. And seems to be a huge improvement. The fluids warm at the moment so I’ll check in cold start. I’m going to replace that hose anyhow maybe it won’t make the difference but from what I’m seeing it may do also.

All fun and games!