Old Engineer & David C,
As you have both been really helpful, I just want to run something past you both from my thoughts.
On looking through the paperwork I have for this car (only had it a week) I note that on a previous MOT there was an advisory (Nearside rear road wheel with a slightly distorted bead rim). As it doesn't appear on subsequent MOT's I can only presume that the wheel was replaced. Having seen the cost of one wheel new (just over £400) I can only presume that a second hand wheel was fitted.
My car is a post 2008 ti, so has weight reduction being a phase 2 model. Part of the weight reduction was to use lighter alloys. 12500g v 15000g.
Now here is the science bit, would having alloys with differing weights on the same axle, result in a balance issue under braking? Whilst I said that it pulled left under braking, I was being a bit generic. It is more like the nose of the car twists left when the nose dives, right at the of hard braking. Add to this it appears that the rear pads were changed about 11 days ago with not much miles done since so they are possibly not fully bed in yet.
The alloy which is closer to the caliper is on the left the one which is further from the caliper is on the right. I am thinking that the original Alloy is on the left with the heavier replacement on the right.
This post led me to think along these lines. http://www.alfaowner.com/Forum/showthread.php?t=121970 (159 Ti Brake Calipers)
I couldn't get the wheels off today to confirm this as I had just ripped out the old Power Steering Reservoir and replaced with the new design and green fluid before the rain came in.
Would be interested in your thoughts on this, the car's not a shed (honest).