Avid BB7. A stupid question

I know the saying goes, "there are no stupid questions, just stupid answers"...

But, having just ordered a mid drive to fit to my tadpole trike, I figured I'd better give her a service first.

Everything's clean, oily, and not oily, as it needs to be.. however I figured I'd better check the brake pads.

To get to the disks on a trike I needed to remove the wheel . Easy. Then remove two 5mm hex head bolts. Not easy.

Then the brake just lifts off.. and that's where the problem is.

There's a bolt, then two spacers, one convex, one concave, the brake, then two more convex/concave spacers.

The pads are, as I suspected, fucjed. Unfortunately the "comparable" ones I picked up just won't fit.. So I replaced the brakes on the adapter, and clamped everything back together. I had to use a dot of copper grease to hold the spacers/alignment together..

And now the stupid question... given I didn't adjust anything, and everything's the same as it was before... How come I now have a massive massive pull length on my brake lever?.. Like I have to pull half way before anything happens, and how do I readjust the buggers? There's a small adjust screw on the levers, just like any other, but turning it has basically no effect.. like 10mm of travel maximum.. And I need to take at least 20 out..

Or am I just being incredibly dumb?