My bars are drilled, but there must be something wrong with the routing. These have NEVER worked well, even when new 20+ years ago. It could be the cables, the calipers or the pads too I suppose. In any case I'm going to replace the cable and housing, and also the pads, which themselves were replaced a few years ago the last time I rode the bike with any frequency and it didn't help much.

I'll check for weird bends in the cables.