Was thinking of bring my car up to AL to have a look at a bit of a problem with my 2000 156 2.5.
The car has an issue with the steering. Recently the steering started making a whining noise. I topped up the PS fluid as it was low which obviously suggests a leak.
Since this problem arose, when driving, I've had to fight to keep the steering consistently in the straight on position. As though the PS is late to react and then over-adjusts and I have to steer opposite. Nothing dramatic, but annoying as I have to keep making tiny adjustments to drive a smooth corner or straight line.
Also I had KwikFit do the tracking and I saw all the numbers on the screen still red at the end of the session. As a result the susp was much more crashy when driving out.
I would think that you have problems with the upper and lower wishbone ball joint or the inner track rod ball joint, any of these will make the steering wander, the los of fluid could be down to either a leak just above the exhaust or to the cooler, OR if your pump is on the way out then return pressure can overfill the res, just like when your steering the car with the engine off.
On my last 156 there was, and it was most noticeable with the engine turned off. A good 10mm in either direction before any resistance was felt.
To cut a long story short, in my case the car had been driven a short distance with the aux belt removed, and the extra load needed to steer the car had damaged the rack near where the column attaches inside the car.
There's no play in the steering while stationery. It's most noticeable at motorway speeds when only tiny amounts of steering input are needed. The power steering feels like it's resisting at first and then gives. And the power steering puts too much steering to the wheels.