Tonight, after changing the ripped Ebay Manifold boot that some turd put on it. I began my brake job. Went super smooth. Then!!, I could not get the caliper with new pads back on the rotor. It was the front btw. On the bottom there is this slight nipple that stops you from sliding the caliper into position. I finally gave up. I have a clymer service manual. It says it should slide right in. Well it won't. Any ideas?