The reason the clevis pin dropped out was the failure of the the split pin and and it's disappearance. Definately one where the instruction "always fit a new split pin" should be followed. Can happen on the clutch as well. The holes in the clevis wear oval which gives too much movement in the pedal before anything happens. The position can be adjusted on the push rod. The clutch clevis wears the worst and AFAIK they are NLA. I'm in the UK but will buy a couple of sets for brake and clutch from "anywhere" if they are available. Must be the correct ones though. You can lose close on 1 1/2" at the clutch pedal when the wear is bad which makes the the clutch action short and very unpredictable. Currently I've got mine adjusted out to the limit and it's OK but it needs changing to a new or better one.