Harsh Vibration full lock

[lynns hubby]

Having had 940s for the last 12 years I know they have a tendency to "Skip" on full lock but I have never felt anything like what it is doing now.
Turning into a tight space on full lock it can only be described as a Harsh vibration accompanied by a low groaning. It can be felt through the whole car.
It seems to be more prominent on R/H lock.
I have jacked the car up and checked all the suspension bushes for excessive wear and they all seem fine. I know the "D" shaped ARB bushes got an advisory last MOT but there does not seem enough play there to worry me.
I have checked the Rack for security as I thought that maybe the mountings had become loose but all is well there too.
General driving and the steering feels and sounds fine.
It has only started over the last couple of days and I have done nothing to any part of the steering or suspension.
Any ideas would be greatly appreciated as I have exhausted any thoughts that I had.

[Rumbo]

I'd try changing the fluid and take it from there...

[Rumbo]

Had my ARB bushes and ball joints changed a few months ago and it made a nice difference by tightening everything up...Get them sorted too,I would

[Alasdair1]

It sounds like the power steering fluid is either low or past it. Mine used to do the same in cold weather. It groaned and vibrated like mad when on full lock until it warmed up a bit. It had been contaminated with water/condensation over the years. Another thing to check is that the power steering belt is tight.
Does it do it whilst stationary or only when driving?

Alasdair

[lynns hubby]

Thanks for the info chaps. I have drained and flushed the power steering system,. that was my first thoughts.
I guess I need to change the ARB bushes and report back.
I have just given the old girl a major service including ALL belts, so the Power steering belt should be fine.

[TonyS9]

Did you use the proper 11.9mm belt?

I also find I get vibration after the mot testers (or me) move the steering around without the engine on and sucking in air past the old seals.

[lynns hubby]

It was the 11.9 MM belt, I know there is a lot of confusion around belts for these.

[lynns hubby]

OK, Changed the front ARB Bushes (all of them) and changed the ball joints.
It has made a slight difference. Dosent feel quite so harsh. Strange I know as you would expect it to be the same or gone!!!!!
Beginning to wonder if I have air in the system. I did bleed the system after the flush. Wheels off the ground and full lock left to right 6 times.
I would have thought the system would have bled itself after a while, thats why I am thinking air in system and got slightly better.
Any more thoughts on the subject?

[Alasdair1]

It could be air in the system but I would have thought it would have cleared itself. It may be drawing air in on the low pressure side of the pump. If it was a leak on the pressurised side it would I assume show up as a leak. Check the conditions of the hoses and also the joints are tight and sealed. Another point is it may be the pump or perhaps pressure relief valve? but I would start with the low pressure side between the pump and reservoir.

Alasdair

[bgarston]

Originally Posted by Alasdair1

It sounds like the power steering fluid is either low or past it. Mine used to do the same in cold weather. It groaned and vibrated like mad when on full lock until it warmed up a bit. It had been contaminated with water/condensation over the years. Another thing to check is that the power steering belt is tight.
Does it do it whilst stationary or only when driving?

Alasdair

Mine was doing the same. New fluid helped a little but it was the seals on the steering rack that was causing the issue - one new rack later and normal service has resumed. .