With regard to the rear-wheel brake cylinders for the Classic Mini, the choice is huge, no fewer than six (!) Different types! This is confusing and can lead to the wrong choice from an excessive braking to a poorly braking rear. Especially when you are only replacing on one side. The differences in the wheel brake cylinders are in the diameter of the bore and the piston. It is best to measure the size of the bore and / or piston during disassembly and to order the same item as a replacement. The problem is, who says that this is still the original copy? So first do homework and then order the right part ... Depending on the year of manufacture and the specification of the Mini, the manufacturer changed the size at the time.