i dont have any experience with the mazda 6, but i have done rear brakes where the piston needs to be turned. i use needle nose pliers, and turn and push at the same time. i would also flush the brake fluid, so if you are going to do that, if you open the bleed screw, it makes it a bit easier to turn the piston. if you do open the bleed screw, it is imperative to bleed the system after you are done. the ebrake, again, dont know what type you have. some have a set of shoes that go inside the brake disc, some have the caliper actuated by the ebrake cable. if yours has shoes, and i bet it does, and you need to change them, you probably will need the brake discs, too. the shoes will wear the inside of the disc, so there will be a ridge the disc that the shoes need to clear in order to remove them. you loosen the ebrake cables inside the car as much as you can, then there is also an adjuster that is accessible either from the back of the brake shield, or a hole in the brake disc. if a hole in the brake disc, you will have to rotate the disc to find the adjuster, then back off the adjuster as much as you can to get the shoes to clear the ridge. this can be a pain in the butt job, on the millenia it is. the hub is in the way, i pulled the hub, then it was really easy. if you need to pull the hub, the nut is really ON there. i have impacts, so it is not a problem. if you do change the shoes, make sure you get the correct parts. aftermarket is really confused on ebrake shoes, and you have a very good chance of getting the wrong ones. not fun if you get it all off, only to discover the shoes are wrong. then the car is down for a long time. get a couple cans of brake cleaner, i really like the red can of crc, while it does cost more than the store brand, it cleans way better and faster. i have used store brands at walmart, oreilly, and autozone. none can compare with the crc. once in a while it will come on sale, and i really stocked up the last time. but i find that whenever i need something, it never is on sale. make sure you have a lot of brake fluid, i like dot 4. watch out for dot 5 silicone, it does not work in abs systems. there is a dot 5 that is non silicone, that will work fine.