New switches for the signal stalk are expensive. To fix the "click and hold" function of the signal stalk, I have been told you can use a very small round file to file out the indent that the post is held in while signaling. The problem is that over the years this small post wears the material down and you no longer have a nice indent to hold the post.
Check out this old thread, very informative!
http://index.php?topic=554Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both tops
1994 E420