On the rear caliper, remove the adjusting bolt FOR THE PADS, if you still can and coat it with never seize, also take out the two allen bolts that mount the back half of the caliper housing and clean out the mud etc. re-grease with a good marine grade grease!!!!! The little adj. nut inside the caliper can't be bought separate, you must buy the whole caliper, $220 BUCKs !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!