'01 A6 with 95k…I have noticed intermittent hard turning to the right at low speeds…only to the right though, turning left is fine. It feels like there is no power steering, then all the sudden it will start working. It does NOT seem to be temperature related. Usually it clears up after a few minutes of driving, but it has gotten worse. Does this mean the whole rack needs to be replaced? Would flushing the fluid help at all? Thanks.
Have you checked the level of the power steering fluid? You might be able to fix this merely by topping up the PS fluid in the pump. At this age of car, it wouldn’t be surprising a PS hose might have sprung a small leak and the fluid level is now low, which could cause the symptoms you are reporting. Sometimes a hose will only leak when you hit the steering stop, so most of the time it isn’t leaking and the level only drops a little each week.
yeah i checked the level…it looks okay
There’s usually a valve inside the rack that allows the fluid to go where it needs to go. Maybe it is clogged or bad. That may mean a new rack, unfortunately.
When you put the car up in the air on the front, does everything look normal as you turn the wheel? No interference with other stuff?
Not sure if a pump would cause that problem. One would expect bad fluid would cause issues in both directions. Not sure if a fluid change would help.
Be careful. The first thought that jumped to my mind was the spool valve in the rack, as Remco suggested. But a problem like this can be caused by a failed ball joint or tie rod end, and if that goes undiagnosed it can result in catastrophic failure and a crash. You need to get this on a lift ASAP and get it looked at.
My money is on a failed joint.
the problem comes and goes…if it was a one of the joints it would just get progressively worse right? There isnt any “looseness” and no odd noises when turning. Is there something I can flush in there to “unstick” that spool valve? A power steering cleaner of some sort? Thanks.
Joints can act as erratic as any other cause. And you cannot tell if it’s a joint from behind the wheel. I urge you to get this checked.
No, you cannot unstick a spool valve. The rack needs to be changed.
Attached in a drawing of a rack for an A8. Yours is probably very similar. The valve, which they’ve designated a “rotary valve”, is not amenible to flushing, nor is it deisgned to be field serviced.
http://www.audipages.com/Tech_Articles/susp_whls_brake_steer/srack.html
Perhaps that’s another good reason to get it to a shop. A bad joint will be far less expensive to replace than a bad rack. Hopefully it’ll be the former.
Very good point, mb.
I’m going to say either a lower ball joint or an upper strut bearing.
Tester
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Thanks for your replies, I tried the easiest/cheapest thing first: added half a bottle of Lucas power steering conditioner. I drove it around for about a half hour and no sign of the problem…we’ll see if that fixes it…
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Did that resolve your issue? I am currently having the same issue… I do suspect a bad check valve as I can hear the fluid flowing into the cylinder as I turn right… when turning left everything absolutely normal. I’m gonna check my tie rods and ball joints today and flush the system while adding Lucas and fresh PS fluid to replace the old fluid. Hoping I can avoid having to buy and install a new rack. #fingerscrossed