j_e_r_e_m_y

Apologies if this has been covered in another thread (did a cursory search and didn't find what I was looking for), but I'm trying to figure out how to get better performance from some vintage Dia Compe 505 brake calipers and 202 levers that were original to an early 80s Schwinn Voyageur.

I attempted modernize the brake system with Tektro R539 calipers and TRP RRL levers, but that hasn't worked out - the tires on the original 27" wheels rub up against the underside of the calipers. However, there was plenty of clearance when I had the original Dia Compe 505 calipers and 202 levers on the bike.

So what I'm looking for help with is getting the old calipers and levers back to a state where they have the snappiest and best performance possible. Right now both feel spongy, slow, and like they would let me down spectacularly in an emergency.

Are there ways to get more snap back into the levers? They return to neutral very slowly and just feel soft when pulled.

Are there any tricks to keeping vintage calipers on center? Both these and another pair of old single pivot brakes I have tend to push one arm up against the rim after the first lever pull.

Thanks in advance for any advice you can give.