For a car that’s been driven three-fourths of the way to the moon, the exterior is in pretty good shape. Down below is a different story. The rear sub-frame is very rusty with a quarter sized hole on one side. We had planned to add a larger rear sway bar which requires lowering the rear sub-frame anyway so it isn’t a huge additional expense to add a replacement sub-frame to the list of parts needed.
The MINI multi-link rear suspension uses four control arms that run from the sub-frame to the wheel carriers. The stock arms are just folded steel and should be replaced at 100K miles. Since we’re planning to add a larger rear sway bar, we usually recommend replacing the control arms at the same time. We want to add height-adjustable coil-overs in the future, so we opted to go with stock control arms in the upper position, and adjustable arms in the lower position. This will provide the additional adjustability we need to dial in the right amount of negative camber. We like to run with 1.5 degrees of negative camber and 1/8 inch toe-in for the rear of a MINI.
The first order of business was to assess the damage; knock off as much rust as possible; use rust converting primer and paint on the parts we wanted to preserve; and get the parts ordered for the eventual rebuilding of the rear end.
