So shoes fit the drum--same radius. Start the arm as far back as the cable will let it if its the right cable. shoe lining material can make a hell of a difference but genuine shoes should be good. Is the drum rusted & smoothed up rather than totally got rid of down to the iron liner as sanded rust can be very slippery. If genuine shoes the end pad should sit full on the cam bad. Is the cam offset from the shaft. That wouldn't work or make it better lift on one & less on other shoe--so i didn't say that. My AT1 rough old thing that it is, stop overs great on the front. Had a DT1 brake plate that had the edge of the speedo drive center bit chipped away for half the circle where it sits up to the hub bearing, so when the wheel was super tight it cocked the brake plate over a little from square & turned a solid brake into a spongue. Any of that you could prove by leaving the axle slightly loose for a brake test.