Change pads on 07 fatboy

Yes, the pistons will have to be pushed into the calipers. After removing the calipers from their mounts, remove the old pads. A C clamp works well for pushing the pistons in, just be careful not to damage the pistons. Using one of the old pads to push against may help. After installing the new pads, and remounting the calipers, don't forget to pump the brake levers until they feel firm. Also check the brake fluid levels. Good luck!

For front brake pads replacement you need only usually wrench set, inclusive 7 mm allen key also. But for rear brake pads replacement you need obligatory a special caliper piston pressing tool, in order to press back rear caliper piston with parking brake automatic adjustment!!!
For front brake pads. You should buy the brake pads (with wear sensor). For change front brake pads you must raise vehicle, remove wheels, extract the retaining spring of the caliper, and remove the caliper as follow:
1. Do not disconnect the brake hose from the caliper, and do not allow the caliper to hang by the brake hose!
2. Remove top and bottom caps (on back side of the caliper) for access to guide pins, then unbolt and remove them from the brake carrier. Remove the caliper.
3. Now you must thoroughly clean the brake calipers (free of grease).
4. Remove outer brake pad from brake carrier.
5. Pull inner brake pad out of brake caliper piston.
6. Check up the brake fluid level on the reservor, and emptying if neccessary!
7. Push piston back into brake caliper housing.
8. Install inner brake pad (with expanding spring) in brake caliper piston. (Arrow marked on pad - if exist, must point in direction of brake disc rotation when vehicle is moving forward).
9. Install outer brake pad into brake carrier.
10. Bolt brake caliper housing to brake carrier using two guide pins. Tightening torque is 25 Nm.
11. Install both caps.
12. Insert retaining spring into brake caliper housing. Important: Depress the brake pedal firmly several times while the car is stationary so that the brake pads adjust to their normal operating positions!!! Check brake fluid level and top up if neccessary!!!

Take the two bolts out that hold the caliper into the caliber bracket. Look at the pads and the anti-rattle hardware and make sure you know how it all goes in there. Remove and replace the pads and hardware.

You'll have compress the piston back into the caliper. I use either a large C-clamp or a large pair of slip joint pliers to compress the piston. Use a rag or a couple of pieces of wood to protect the finish on your caliper.

Once the piston is completely compressed into the caliper, carefully reposition it onto the caliper bracket. Install the two bolts and torque them to 20 foot pounds. Step on the rear brake slowly several times until you get a full firm brake pedal. Test the brakes before you ride the bike.

Good Luck
Steve

There are two bolts that hold the rear caliper into the rear caliper bracket. Remove these two bolts and the caliper lifts out of the bracket.

Notice how the pads and the anti-rattle hardware is positioned in the bracket. Replace the pads and hardware making certain that you get the fiber side of the pads against the brake rotor.

Now, you must get the piston back into it's bore. I use either a large C-clamp or a large pair of slip joint pliers to press the piston back into it's bore. Use rags or thin pieces of wood to protect the finish on your caliper.

Once the piston is completely pressed into it's bore, carefully replace the caliper back into the bracket without disturning the pads. Slowly depress and release the rear brake pedal until you get a full firm pedal. Test the brakes before you ride the bike. Failure to properly service the brakes on your bike can result in serious injury or death. Make certain that you do this job correctly or take to an experienced person to have it done. If your bike quits it makes you mad, if it won't stop, it hurts you.

Ride safe.
Steve

For front brake pads replacement you need only usually wrench set, inclusive 7 mm allen key also.
But for rear brake pads replacement you need obligatory a special caliper piston pressing tool, in order to press back rear caliper piston with parking brake automatic adjustment!!!
For front brake pads. First you must verify yours front brake disc diameter: 280 mm or 288 mm. (On my car y have 288 mm). After that you can buy the brake pads (with wear sensor). For change front brake pads you must raise vehicle, remove wheels, extract the retaining spring of the caliper, and remove the caliper as follow:
1. Do not disconnect the brake hose from the caliper, and do not allow the caliper to hang by the brake hose!
2. Remove top and bottom caps (on back side of the caliper) for access to guide pins, then unbolt and remove them from the brake carrier. Remove the caliper.
3. Now you must thoroughly clean the brake calipers (free of grease).
4. Remove outer brake pad from brake carrier.
5. Pull inner brake pad out of brake caliper piston.
6. Check up the brake fluid level on the reservor, and emptying if neccessary!
7. Push piston back into brake caliper housing.
8. Install inner brake pad (with expanding spring) in brake caliper piston. (Arrow marked on pad - if exist, must point in direction of brake disc rotation when vehicle is moving forward).
9. Install outer brake pad into brake carrier.
10. Bolt brake caliper housing to brake carrier using two guide pins. Tightening torque is 25 Nm.
11. Install both caps.
12. Insert retaining spring into brake caliper housing. Important: Depress the brake pedal firmly several times while the car is stationary so that the brake pads adjust to their normal operating positions!!! Check brake fluid level and top up if neccessary!!!

Please rate my response. Thanks!

You don't have to but you should pull the caliper anyway, to clean it and check the anti-rattle spring.

loosen the bleeder screw and try to press the caliper in some.

Per Chilton Auto repair manual:

Removal & Installation

1. Raise and safely support the vehicle.
   
2. Remove the rear wheel.
   
3. Siphon a small amount of brake fluid from the master cylinder reservoir.
   
4. Insert a small prybar through the caliper opening and pry the caliper cover (using the outboard brake pad) to bottom the piston in the caliper bore.
   
5. Remove the caliper slide bolts.
   
6. Remove the caliper from the anchor.
   
   WARNING Support the brake caliper with mechanics wire. Do not let the caliper hang by the brake hose.
   
7. Remove the brake pads from the caliper.
   

To install:

1. Install the brake pads onto the caliper.
   
2. Lubricate the slide pin bolts with grease provided with the brake pads, or suitable silicon grease equivalent.
   
3. Install the caliper on the anchor and tighten the slide pin bolts to 18 ft. lbs. (25 Nm).
   
4. Install the rear wheel.
   
5. Lower the vehicle.
   
6. Pump the brake pedal several times until a firm pedal is obtained in order to properly seat the pads.
   
7. Refill the brake fluid reservoir to the proper level.