Yeah, that can be a pain. Is it block or cam driven?


I should preface this: I've never had a 940, but unless they changed just the distributor for the 940's B230 engine, it should be right.

Either way, the challenge is always getting force on the rotor straight off. It's like trying to remove a pulley.

Two things I would try somewhat gently: Put an open end wrench or pair of pliars under the rotor. Grab both the handle and the tip and pull up (or back). You can also try sneaking a screwdriver or knife blade between the base of the rotor and the place where it sits and wobbling it back and forth.
You might even be able to get your thumb and index finger under the rotor and try to sort of squeeze it up (or back). That can work very well if your hand doesn't mind a bit of pain.

Once the catch comes loose, it should come off easily (read zero force) and all at once.

Good Luck! Make sure you don't bend your distributor shaft!!