Panic mechanic rings true to me.  Similarly, big gang ride for my bachelor party in Fernie for a long weekend.  First ride on Friday with a smaller crew until the rest joined up.  My Sram G2 RSCs... got janky in the Mt Fernie park.  Lower screw on the rear brake pivot had fallen out.  Remind me again why there's two screws, one from the top, and one from the BOTTOM where it can rattle out locktite dried out?  Why isn't this an axle through both bearings with a cotter pin or something for backup. 

Anyways Fernie shops too busy to help, but have parts.  Random camping up coal creak time to get creative on wrenching.  Somehow my my 3-way hex wrench was the right diameter to use as a press to extract the eff'ed bearing race, good.  Ok, now how the heck to press in the new bearing without effing it?  Chain gauge tool as flat surface, and campfire axe to tap it in?  Clutch success, back to the campfire and riding the rest of the weekend!