How to ID MkII piston post??

[Peter Laidler]

Difficult externally! But internally, the Mk2 post has a deeper hole internally for the longer piston post plunger. You could use a shorter Mk1 plunger in a Mk2 piston post but to achieve what? If you use a long PP plunger in a Mk1 PP, the end of the rod batters the end of the shallow housing and causes mayhem and jambs the spring onto the rod. This was all done to further cushion the violent unolocking cycle and help cure the high attrition rate of PP springs. It sort-of helped but the attrition rate remained high, even up to the last L4 Bren era. That's the reason why a spare PPspring was always part of the spare parts wallet.