Paul gave some good advise - buy the correct tools for the job. The site he gave carries them. Go online and order the parts catalog for your MB.
Public Enemy posted a fan clutch removal process.
The MB part numbers for the tools you want are in that post:
103 589 00 40 00 - counter tool - metal rod about 1 ft. long. This locks in behind the pulley.
103 589 01 09 00 - special 8mm Stahlwille tool that removes bolt that secures fan clutch/bladed assembly. The counter rod keeps the pulley from moving so you can loosen the bolt. Don't over-tighten on assembly. The head of this bolt is SOFT and easily rounds off.