Changing brake pads.
I thought it would be a straight forward job, taking just 10-15 min. But it was not going to be this time :) I removed the metal piece (red square) and tried to push the metal pins (yellow) in the direction of the arrows. No chance! I tried with a hammer. Still not moving at all. It was time to get serious. I picked up my angle grinder and cut the pins in several parts. I used heat and a hammer.
In the end I had to drill the bits out. :(
From there on it went very well. I put the new pads in place.
I sprayed the new pins with copper grease, my best friend. I use it on every bolt, nut and piece of metal that I put together. I is very easy to take apart again, even after some years.
Finally I put the metal spring in place to lock the pins in place. Job done! A couple of hours later but anyway. :)