This is how the pedal comes off my W123 '82 240D. The W124 may be different.
My 240D has a one-piece molded-plastic pedal/hinge/base assembly. The base slides onto a metal tab welded to the floor, with a plastic clip through the base to secure it to the metal tab. Pull out the plastic clip, slide the pedal-base up off the metal tab, then pull the pedal/base assembly down to separate the pedal's connecting bushing from the metal rod that connects to the accelerator linkage.
Hope this helps.

Happy Motoring, Mark

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DrDKW