Originally Posted by
unterhausen
That's what I thought when I read your post. There really isn't anything stopping an inattentive mechanic from putting them in backwards.
I found out how important the pins were on a 200k when I had cut down some pads to clear my forks. I ended up losing a pad and I cut another one in half so I could have the full compliments of pads. They fell out more than once, even though I knew about it. I didn't know I moved my bike backwards that much.
I find it difficult to believe that the pins sheared off from stopping a bike rolling backwards. I am guessing that the pad holders were installed backwards (right side on left, etc.), thus in hard braking when going forward at speed, there could be a lot of force on those pins.
When I worked at a bike shop almost a half century ago, I was the only mechanic there that could figure out how to work on rod brakes, thus I was the one that worked on the vintage bikes like Raleigh DL1. Their pads did not have pins, would easily slide out backwards if you were stopped on an uphill and used the brakes to hold a bike from rolling backwards.