You must know that this thing is very common on B class... Simply, bumper have poor designed catch clips (mostly on left side) which easily can be wear off and only solution is retrofitting new clips or new bumper.
Every time when you return bumper in position you slightly wear off clips until they loose itself for ever...
I have same problem (but not very big hole) as I removed and painted bumper two times so far because damage...
Every time when you return bumper in position you slightly wear off clips until they loose itself for ever...
I have same problem (but not very big hole) as I removed and painted bumper two times so far because damage...