Hi Joe,
On a 190 it may be worth replacing the steering lock assembly as well as the tumbler. There is an updated steering lock with a stronger connecting piece between the tumbler and the electrical portion of the switch. If the steering lock has been replaced in the last 10 years it should already have the new piece.
Regards,
Randy D.

------------------
W.R.Durrance
ASE Master Tech
Mercedes Tech 19 Years