The lower bolt on one of my 740s rear shocks was fused to the metal sleeve. I couldn't get it out until I got a pair of vise grips on the sleeve to hold it in place.
--
Paul NW Indiana '89 740 Turbo 108,000

Sounds like I was just in too much of a hurry.

Chances are there is some undercoating and other dirt and such on the bolt threads.Nate'sextra leverage trick should work, if not you may also want to take a wire brush to the exposed bolt threads and clean them up so you don't have to fight it off.
That said, an impact wrench makes short work out of it :-)
--
-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel

I assume by "shocks" you are referring to the rear shocks and not the front struts. Anyways, no, you shouldn't need an impact wrench. Get a good box-end wrench and loop another one over the open end of the wrench (hard to describe) and you should get enough bonus leverage to break them loose. For the oil drain plug, I use a 1" wrench. The metric size would be 25mm, but a 1" wrench works fine. Good luck,
Nate Gundy
--
'86 240DL sedan, 260K miles, M46, K cam, 25/21mm sways, 260 front and wagon rear springs; http://valvespringcompressor.weblogs.us/