SRAM eTap AXS Service Manual page 7

Remove the pad spreader.
4
Use a plastic tire lever to push the pistons back into the caliper bores.
5
Repeat steps 3-5 until both pistons contact the spreader at nearly the
same time.
Reinstall the brake pads and install the wheel according to the
6
manufacturer's instructions.
Tire lever
Disc Brake Pad Advancement Procedure
Tire lever
7