Try to find a used part from a wrecker/used parts house.
Also try using oil w/ teflon. It's amazing how well it lubes but, as the group as warned, it WILL come back again. Also if the bearing are very worn, then the 'lube' may not work at all! Radio Shack makes a teflon embeded oil, PN 64-2301A. Give it a shot!
Regards . . . . JimF
'94 S500 Cpe
Visit my Mercedes Web Page