Thank you guys
Well first of all I had to redo the paintjob twice (my bad) I don't know if that is the cause, but many of my plated parts didn't fit very well. Therefore I decided to cut the body to make them fit and, of course, it broke. I also have a floating wheel. Checked the chassis but didn't find any mistakes I made.
The major issue is the poor fiting of the plated parts. If you decide to strip them, make them fit and repaint every chrome part, it is possible to make a very nice car out of it.
Cor