there's a nice write-up on the procedure for a 300SD (W126) here:

http://www.peachparts.com/shopforum/showthread.php?t=92874

I did this recently and left my comments there. dry fit the captive nuts before bolting up, might save you the trouble I had.

__________________
mjk

'84 300SD 119KMi (Liesl der Diesel)
'84 300D 326KMi when the oil left (former parts car)
'82 300SD 253KMi (new parts car)