Need a one fo sure, more is better. I'd rather rebuild them then replace them. The M108 wheel cylinders were way to pitted to rebiuld I had 6 wheel cylinders set back but gave one to Bjorn. I was thinking at least one from the M108 would be reuildable but that hasn't been so. Bad thing about this is when I sell axles to the swamp buggy folks, they chop off all the brake stuff and toss it. Several folks have said they would return them but no one has.