On my 1990 300TE 4Matic I have been trying to remove the rotor arm drive sleeve so I can replace the timing cover seal. The drive sleeve is now half removed. The remaining cylindrical part is seized in the end of the camshaft. It is rusty all around it. Does this sleeve after removing the securing bolt supposed to just pull out or twist out? It looks like someone tried to remove it prior to my ownership and it was 90% broken (cracked). Will I have to remove the cam to remove this remaining piece or should I try to drill it out? Is this a common problem?