what are you talking about?
is the arm going too far, or parking in the wrong spot? that's where the tab comes into play
or are you meaning that the blade isnt staying in contact with the window?
if the blade isnt staying in contact with the window, the spring in it is likely worn out.
get a new arm -- this will also help with keeping tight on the splined shaft. --- the new arms do not have the oposite splines, they're made slightly smaller, and the splines are pressed into the arm when you tighten down the arm. if you've stripped out the mating surface of the arm, that's why it kept getting loose.
