I have been doing a bit of winter servicing on the M3W. Today was replacing the front upright ball joint rubber boots, as they were all starting to perish and split. I was surprised to find that all four joints were almost dry with hardly any sign of grease in them when the boots came off. I thought I had got to them just in time but the final one was quite badly worn and needs replacing, the new ball joint, impact wrench and 46mm socket are on their way.
My car is a 2013 one with almost 26,000 miles on it. If your car is a similar age I would suggest an early replacement of the boots. They are cheap and easy to replace and along with some new lubricant will probably give you another 6 years trouble free use.
At least you can replace upper and lower ball joints. On the Aero chassis cars the lower ball joint is bonded into to the upright and secured with set screws, so it can't be replaced.
A new upright is £660 +VAT. They seem to last about 40,000 to 45,000 miles.
