Wiper linkage and our products have change since I wrote this page, please visit linkage size and I will try to help you.
The recommended maximum ball joint diameter is 14mm and a collar under the ball of less than 9.5mm.
It is possible to file the clip to fit a larger collar (up to 11.5mm) but we do not recommend it as it is not always successful, please see last image.
If you have a larger linkage (16mm ball joint) see our repair plate
The easiest way to measure the ball joint is to cut a cardboard/plastic template with a 9.5mm slot, if it goes under the ball the repair clip will fit.
It can be filed out to 11.5mm see below.
The slot can be made larger using a hand file or Dremel. It can be held using mole grips and a vice.