As always, have your service manual handy, and follow their instructions. I am putting this together as a visual aid, not a step by step instruction to cover every make and model. Make sure that you have all the right parts and tools before you start. Be careful with Allen head fasteners, they tend to strip fairly easily.
Allen Socket for caliper bolts
Allen Socket for brake pad pins
Needle Nose Pliers
Brake Parts Cleaner
Brake Parts Lubricant
Expect to spend 30-45 minutes on each side if this is your first time, it will get quicker after that.
This is being done on my 06 Ninja 636.
This is possible to do with the bike on the side stand, however, I prefer to support the bike on a swing arm stand so that it is "upright", and I have easy access to the calipers on either side of the wheel, with the ability to turn the handlebars as needed.
-Loosen the brake pad pins (B), then the caliper bolts (A). Loosen the pins while the caliper is still bolted to the bracket because it becomes difficult to break them free when you are holding the caliper in your hand.
-Remove the caliper bolts, remove the caliper from the bracket, and remove the brake pad pins from the caliper.
-Remove the pads and springs from the caliper.
-Clean the surface of the pistons, and the inside of the caliper. This will ensure that you do not push dirt and brake dust into the pistons bore, which will destroy the seal and can potentially cause a deadly leak.
-There are several ways to press the pistons back into their bore. I do not recommend using a screwdriver to pry between the pad and rotor, this will often warp or gouge the rotor. (I heard from another member on here that he uses a pair of needle nose pliers, so I tried that method this time to see how it works. It worked out okay)
(You'll see that my pistons have not been pressed in all the way. I did not actually replace my pads, I took the pictures simply for the purpose of writing this "How To" for the forum. The edge of the piston should be flush with the caliper body)
-Ensure that you are pushing the pistons evenly, top/bottom/left/right; and take your time. The brake fluid is a fairly thick fluid, and has to pass through very small passages in the banjo bolts. Firm, steady pressure will get the job done. I like to open the bleeder screw while pushing the pistons back into their bores, which discards the old, dirty fluid, and I will refill with new brake fluid after the pads have been replaced.
-clean the caliper, and loosely bolt it back into place.
-Lubricate the backs and sides of the new pads, and the brake pad pins, with Brake Parts Lubricant. Be careful not to get any on the friction lining surface.
-Slide the outer pad into place between the caliper and the rotor. Ensure that the friction lining is facing the rotor (sounds basic, but I've seen it go wrong way too many times)
-push the pin through the outer hole in the caliper and the outer pad. Place the inner pad in its new home, and put the anti-rattle spring on top.
-Slide the pin through the spring, and the inner pad. Pressing the spring in to get the pin through usually pushes the inner pad out of alignment. You can reach in to the inner area of the rotor/caliper and push the pad back out. It can be tricky, but you'll get it.
-Tighten all fasteners, and torque to spec. If you do not own a torque wrench, GET ONE. A dab of BLUE lock tight on the caliper bolts is not a bad idea.
Before going anywhere, pump the brake lever several times to bring the pads into place against the rotor, otherwise you won't be able to stop when you go on your test ride.
Seating the pads, or "burning them in" is a very important step. Complete 30 stops from 30 mph with 30 seconds in between. This heats the pads and rotors, and mates the profile of the friction surfaces, to provide peak performance.
Wash your hands, have a beer, and be proud of the work you have done