If your caliper is getting hot then you have at least one sticky piston. You didn't say what XT660 you had (R/X/Z). You may also have a sticky caliper slider as well. Bleeding alone will not solve this and i you don't fix it you will end up warping your disk!



Before you waste time on bleeding I would suggest replacing your caliper seals giving everything a good clean in the process. I use caliper service kits from www.powerhouse.uk. Polish the outside of the pistons when they are out to remove any build-up on them. There are plenty of videos on YouTube to show you what to do.



Once you know the caliper and the slider are in fully working condition the brakes should bleed easily and the sponginess should disappear.


Al.