Hi need some advise thinking of replacing calipers and discs, 26000 miles a couple of the pistons in the calipers are a bit lazy even though they are cleaned often the rims on a couple of the pistons are chipped and the bobbins on the discs are very loose and rattling like fully floating discs not sure if they are suppose to be that loose not sure what to do for the best an advise would be appreciated thanks.