To engage the o/s indicators requires and extra 'tug' on the arm of the switch. I've pulled it apart - but unfortunately didn't take photos - and it appears the contact points are worn. They are similar in appearance to distributor contact points.
I'm wondering if anyone has suggestion how I could either build up the worn/pitted contacts, e.g. silver solder? or modify the mechanism to gain more movement, e.g bigger ball, stretch spring?
(edit) There are some images here of an earlier 4 contact switch but mine is a 2 contact later version.
Edited by PeterAllen, 20 November 2016 - 12:14 PM.