SRAM MTB Manuel De L'utilisateur page 106

Install the wheel according to the manufacturer's instructions.
5
Squeeze the brake lever several times to position the brake pads to
6
the proper distance from the rotor.
Center the caliper on the rotor, if necessary.
Spin the wheel and check the brake function. The pistons should move
7
freely and there should not be excessive brake lever throw.
If there is no improvement in the brake function, proceed to
8
Caliper Service.
Disc Brake Pad Advancement Procedure 8