Rear Brake Pad Nippile??

[sturvin]

ok so i have noticed the little nipple on the inner pad on the rear brakes.
what the hell is it for and if my new pads dont have it, what will be the repercussions of using these pads??
also i know that the piston can turn counter and clockwise to make the nipple fit in,
so basically what the heck is going on with that thing???

 

[EK9turbo]

It stops the piston itself from rotating against the brake pad, I couldnt tell you a definite reason but am quite confidant in assuming that the brake piston shouldnt be allowed to rotate since the threaded section inside the caliper has to rotate slowly over time as the pad wears. Otherwise the piston could wind its way back in over time and cause uneven brake pad wear.!