Here is a quick and inexpensive little upgrade to the wheel bearing caps on your 928.
You may have found that removing the wheel bearing caps with a channel-lock pliers leaves them scarred up and deformed. Yet very few of us have VW Tool #9165 to do it as per the manual.
Our solution is to drill a hole in the center of the cap as shown and weld a M6 nut onto it. Then, when we want to remove the cap at the track, we simply remove the short screw we keep in it and insert the longer screw we carry along with us. The long screw will bottom out on the end of the spindle and it pushes the cap straight out without a fuss.
This mod will not allow the stock center cap to be used on the stock wheel, for the nut is too high. If that’s your goal, then weld the nut onto the inside of the cap (there is room!) and use a low-profile screw to cap the hole when not in use. Then your center cap will still fit.
This little mod sure has been handy on my race car—I hope you can use it too.