so i have those old 4 piston xt disc brakes (m-739 i think it is) that are similar to the grimeca's. the pin that holds the lever (which also acts as the pivot for the lever) is loose and tends to pop out a bit during riding. so far, i've just put a piece of electric tape underneath the pin so that it doesnt fall out completely. this is only a temporary fix, as the tape loses some adhesive property over time. is there a way to keep the pin in the lever housing? like a shim or something? has anyone else experienced this. other than that, these are the very best disc brakes ive run for general riding.