Ive recently bough this 1

Hi, Ive recently bough this 1.9 diesel Vectra sportwagon and it seems to have some sort of fault with the steering/alignment/tracking. Instantly I had the front discs and pads replaced by my mechanic mate and had all four wheels balanced and tracked by Kwik fit costing £120! Apparently the negative camber toe is out and they cant align, they said the only people who can do that are main dealers and they may need to change suspension? They said not to worry about it though as many cars drive fine with this out of alignment.

Ultimately though Im still having problems, I got my mate to track it again to no avail! On even the smallest bumps in the road, the wheel is snatching both left and right. Between 30-45mph on motorways at 60-70mph it drives a bit better but still snatches slightly from time to time. At all speeds on all surfaces the car pulls both to the left and the right.

The car has traction control and seems to drive better with this off however there is still a problem with it snatching, I know the abs and traction control uses the same sensor and the wheels locked up on me yesterday when I braked quick at 25mph. Also the wheel snatches terribly when braking at average speeds.

My mechanic mate has had a very brief look (while doing the brakes and replacing timing belt) and he said the ball joints/bushes are fine but he noted that one of the shocks are no original. Like I sais, he tracked the front wheels again and said it drives a little bit better (which it did) but seems to be getting worse again?

This is pretty much all of the information I have except that the rear discs and pads are an advisory as they are slightly corroded. Oh and the tyre pressures are all set at 35psi. There doesn't seem to be any uneven wear on the tread of the front tyres, not looked at the back.

Can anybody shed any light on my next steps to get this fixed?

Thanks in advance.

Joel