How to replace Avid BB7 brake pads in "new" calipers? How do you get new BB7 pads to install in the new caliper bodies?  By "new" I mean the ones with the spring steel "cap" on the opening at the "top" of the caliper unit (the side opposite the axle).  

On my c. 2004 Gary Fisher, the silver calipers are closed on the side opposite the axle.  On my 2015 Salsa Vaya the black calipers have an opening on that side, and they have a spring steel cap that clips into the opening.  The upper "ears" on the pads extend up into that space.  

Here is what it looks like from the "top" (looking toward the axle):



You can see the pads through the opening in the cap. 

On the old Fisher, I would install BB7 pads just by pinching the pad-spring-pad "sandwich" and pushing the sandwich into the caliper from the "bottom" (the side toward the axle). This is how all the advice on the web tells you to install BB7 pads.  On the Salsa Vaya, with the cap installed, I can only get the pads all the way in about one in fifty tries--usually one or the other pad will not go all the way in.  Sometimes both pads hang up short. If I take the cap off, then the pads go in fine.  I rode all the way across the U.S. with the cap off because that was the only way I could get the pads into the caliper. What's the trick?
There is a trick: The pads need some "persuasion" to get past the spring clip.  Here is a side view of the pads and the spring clip showing how the pads nest within the steel clip.  This should make obvious why a little force is required to get the pads to move fully into the caliper.



After much frustration, I finally looked at the pad and the clip in that side view and realized that the "ears" on the top of the pad need to be forced (gently) past the narrow, re-entrant part of the cap (expanding the cap outward as they pass).  The force required was more than my fingers could muster, and more than was implied by the instructions I found on an Avid site and elsewhere.

The way I applied the necessary force was by setting a drive pin across the edges of both partially installed pads at their bottom (next to the bottom "ears") and giving the drive a light tap with a plastic or rubber mallet. The pads moved ever so slightly as the ears pushed past the re-entrant portion of the steel cap. A piece of wood or a dowel of the right dimension would be better, and a steel hammer would work fine. No matter what you use, be gentle.