Need info on loose 74 caliper

I got a 74 Swinger with a lose caliper (drivers side front) its bolted in tight with the spring retainers working well, but it still has enough play between the knuckes that it knocks a bit on rough roads and grinds a little on slow stops. I greased the ways/groves and bolted it up and it's great for a little while then it starts in again. What can I do? If I get a rebuilt caliper will that one have the same problem?