I need to rebuild one of the front brake cylinders. I am trying to determine exactly which rebuild kit I need though. My 1958 444 was sort of a transition model with a handful of parts that were used on the 544 rather than the 444, so I am not entirely sure which one I would need. The guy at Swedish Treasures suggested that it is most likely the K113 kit (444) rather than the 273022 kit (544), but I was checking out the pictures of the two kits on SwedishTreasures.com, and the spring from my cylinder looks more like the 544 version than the 444 version.

So what exactly differs between the 544 and 444 front brake cylinders? Is there something that I can measure or look for to distinguish one from the other? How does the difference in spring design affect how it works (if at all)?