So I took the front passenger side window motor out on my 83 300sd to open it up and see what was causing it to be so weak and one of the hex type screws got rounded off. I have no clue how get this out someone please help. Thanks a lot.

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W126 1983 300SD 286,000 miles and ticking
Baby blue exterior Grey MB tex
Recent work:
Replaced air cleaner mounting brackets and heat shields
Replaced alternator, fan and power steering belts
Replaced positive battery terminal
Replaced negative battery terminal and cord
New Duralast Battery

My car needs work.