Thats exactly as mine is too. I looked at one at FastLane and they don't seem to have these teeth anymore. But that look gave me enough confidence to pull hard enough and it came out. Thanks for your help and pictures, they will help somebody in the future...
Now the good part...
The relay has a white stamp on the side saying 21 March 89!!!
Now after I saw that, I simply said: It's time for a new relay, this one did it's part. I looked into the base of the connector and noticed something like a needle from a christmas tree and some dirt. So out with the Q-tips and some dielectric grease to clean up the base and to lube the connectors of this relay and the AC relay next to it. I also cleaned the sides with the teeth and put some wax on it to make it come out a little easier the next time.
Then to make sure the car will start, I turn the key and just wait a bit at the position II. Sure enough, the pumps start and stop after about a second. As these new ones are a lot quieter than the old ones, I even get out of the car to listen to the "silence"!!!
I can't believe my luck. A little grease and cleaning and the thing works again. I tested it a few more times, even with my neighbor listening and it works ...Couldn't all problems end this way?
Thanks everybody for your input.