The "plastic" is indeed a form of Loctite.

Mercedes specifies that these bolts be replaced and NOT reused.

On the W210 I just did, I used a floor jack (carefully) to raise the wrench on the side that required it. On the other side, I simply stepped on the wrench. The "raising" portion has to be done with care, as the goal is to rotate the wrench and to NOT lift the car off the jackstand.

Of course it would be easier with the car on a lift, as the wrench motion would be horizontal and you could put some weight behind it.

ANY kind of caliper--floating or not--has to be removed before the rotor comes off.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles