Snap the brake-pad spacer into place. Most of these will stay in
place on their own and are designed to help you find the correct
Loosen the brake-caliper mounting bolts. If your frame uses an
adapter, you should not loosen those. Only loosen the ones that
come in from the top and control the alignment of the caliper.
Reinstall the wheels on the bike. You should be sure that the rotor
is clean before doing this. If there is any doubt, clean the rotor
with isopropyl alcohol and a fresh paper towel first.
With the brake applied, tighten the caliper mounting bolts. It’s
helpful to alternate between the two bolts as you’re tightening
them. Tighten the first bolt about halfway, then the other, then
finish torquing the first, then the second. This prevents the caliper
from moving while the bolts are being tightened.
If the squeeze-and-tighten method doesn’t work, use the window
on top of the brake to check the alignment of the brake and the
trueness of the rotors. You should be able to see a bit of daylight
between both sides of the rotor and the pads. Spin the wheel to
ensure this is true all the way around the rotor.
If your rotor is slightly off—and most are—you can use a rotor
truing tool, like this one from Wolf Tooth Components, to bring it
back to true. Gently work the rotor in the direction it needs to go.
This can also be done with a small crescent wrench—just be sure
it’s free of contaminants before throwing it on the rotor. ❏