Rear brake caliper

SOURCE: replace rear brake pads

Remove right saddlebag, pull the two caliper mounting bolts and remove the caliper. Do not open bleeder or disconnect line. You will need to push a large screwdriver between the old pads before removing them in order to push the pucks back into the caliper or the new pads will not spread enough to reinstall. Then pull the two smaller bolts from the caliper and the pads will fall out. The pads are different for inside and outside, so pay attention, and remember, after reinstalling, before riding, be sure to pump brake pedal, and it may take a few stops before brakes stop as effectively as before.

SOURCE: Stuck Brake Pad Pins

I suggest pulling the axle out a bit to allow the caliper assy more freedom of movement. Then see if you can get the pins out. If not, you can put something (like a piece of wood) between the pistons and the rotor on the outside and gently pump the pedal to see if that does in fact loosen the pins. But a more fundemental question: is the new floating rotor the EXACT diameter as the OEM (or whatever was on there) rotor? It sounds to me like the rotor is jammed against the pins. If it is the same size, are the new pads the same shape as the old ones (same profile on the metal backing)?

SOURCE: 2003 rear brake caliper lock up on a harley sportster

Check your pads to make sure they are in the right position and haven't started to wear too thin and move.
Check the operation of the pads is real smooth when you apply pressure on the lever (might need someone else to operate it while you look ).
Witth the rear wheel raised off the ground and the bike not running turn the wheel slowly and check to see if it warped. (I used to do this on my sportster by using a couple of car axle stands under the footpeg brackets and raising the bike up on an old hydraulic car jack - might not be the best way but it worked enough for me to get the rear wheel off to change tyres without spending a fortune-an extra pair of hands is really handy(!) here).
Look down the rear caliper and check that no **** from the road has got stuck in there anywhere.
check your wheel alignment - have you adjusted the belt lately or latered the set-up?
Hope something here helps!

SOURCE: Want to replace rear brake pads 1995 Harley Fat boy

Replacing the pads on your Fat Boy is not difficult but you need to pay close attention to the way things are put together as you take it apart. Particularly the little steel pad retainers and the anti-rattle spring. These parts are made and go together in such a way that it's very hard to describe how they go in.

To remove the pads, take the two caliper retaining bolts out of the disc brake caliper. These are usually Torx head bolts. Once you get the bolts out, the caliper simply slides to the front and off of the pads. You'll need a way to push the piston back into the caliper so it will go down onto the new pads. I usually do this with a large pair of slip joint pliers. Make sure you put a rag or something on your calipers so you don't damage the piston or the paint.

Now, look at the way the pads, the little steel pieces at each end of the pads and the anti-rattle spring are in the caliper support bracket. Remove the old pads and parts and install the new pads and parts in the same way. Make sure you put the fiber face of the pad TOWARDS THE ROTOR. Don't laugh, I've lots of people put them in backwards, especially on the back side of the rotor.

Now, carefully slide the caliper back down over the pads taking care not to knock the pads out of there positions. I put a little Loctite 242 (med. strength blue) on the threads of the caliper retainer bolts and reinstall them. Torque them to about 25 foot pounds.
Check the brake fluid level in the rear master cylinder and slowly "pump" the rear brake pedal until the rear brake feels firm. Wait a few minutes and mash the brake pedal one time to the bottom. If it goes down to lower point and then on the next "pump" is higher, you probably need to bleed air from the system.

Open the bleeder valve on the caliper, press the rear brake pedal to the bottom and hold it there, close the bleed valve, and then release the brake pedal. Continue to do this until all the air is out of the system and the rear brake pedal feels firm on the first time it's depressed. While doing this, never allow the rear brake fluid reserviour to run out of fluid. If it does, you'll have to start all over with the bleeding process. Use only DOT 5 brake fluid. DOT 5 and DOT 3 or 4 are NOT compatible and will not mix. If they are mixed, it will cause you a lot of trouble in the future.

Test the brakes before you ride the bike and then again when you first ride the bike at a very low speed. Failure to do this job properly can cause serious injury or death. Brakes must operate properly. Good Luck!

SOURCE: changing rear brake pads..

if the 04 is the same as my 05 ultra (and i belive it is) the rear caliper can not be removed with out pulling the axel out, and taking the 3 big star bolts out will split the caliper in half, (it is a 2 peice)

take the 2 small star bolts out, use a stiff putty knife to push the pistons back, before you pull the old pads out, make sure you take the cover off the master, slip new pads in, start with the frount and put the bolts thru to hold it then the rear

when you retighten the bolts you want the hear a "pop" that means the rear tip of the bolt is past the retaining spring, if you dont hear a pop the bolts will work there way out, (found this out the hard way, $129 new rotor, $195 new caliper)