Those tiny little centering screws on V brakes, a year ago one was unusually tight on one of my brakes so I used a bit more effort, ... which broke part of my XT brake. I do not recall if it was a spring stop or what, but it was a very small piece of metal that cracked right off. So, if it seems to need more force than you would expect, be very careful. I had to buy a new brake unit, this time I bought a Tektro.