Sears didn't have the 22mm oxygen-sensor socket, but Kragen did ($13) much
cheaper than the Hazet/Stahlwille equivalent ($30+). _

I was able to change out the O2-sensor in our 500E without loosening/dropping the exhaust, cut-off the connector, and solder in a BOSCH 13275 4-wire O2-sensor ($45 vs. $120) from a 1995 Dodge Caravan V6 3.8L, check connector connectivity, and torque to 55Nm.

I did the OBDII drive sequence (even though the USA W124's didn't have OBDII)
just to see if the "CHECK ENGINE" light would come on, and she's been
happy for the last couple of days.

BTW: use heat-shrink tubing on all solder joints, and be sure to use the protective fiberglass cover. I use a pair of hemostats to hold them back while soldering.

:-) neil
1988 360TE AMG
1993 500E