Hi all, I've been searching the forums for days trying to get ideas on how to sort the power steering judder when turning at slow speed on my A4 but after trying all suggestions to no avail, I really need more help.

The steering is nice and smooth until it gets just over halfway to full lock both ways, then there is bad vibration on the steering wheel and a groaning noise then right at full lock it's has a bit of a squeal sound. I have changed the power steering pump, flushed the fluid out, replaced the fluid, (green pentosin CHF) raised the car and done the bleeding procedure lock to lock 10 - 20 times with the engine off, 10 - 20 times with the engine on etc, drove for 20 miles to disperse the remaining air that may be in the system but still no change in the steering. I have changed the alternator pulley clutch too before the pump was changed as it was seized and still no difference. When doing the bleeding procedure with the engine off there is a few bubbles in the fluid reservoir but when the engine is on, there are no bubbles at all and the fluid level always stays the same. This leaves me with 2 questions,

1. Is it normal to see bubbles when turning the steering lock to lock without the engine on?

2. What could be my next step to check?


Any help would be great, it's driving me nuts this! Thanks in advance