Center pull cantilever brakes are generally featured on today's cyclocross bikes as well as older mountain bikes. Each brake features a pair of brake arms that are fitted with rubber pads. When the brake is in use, these pads contact the sides of the rim and slow down the bike. Due to friction, the pads wear over time and will need to be replaced periodically. Pads typically feature a set of grooves that act as wear markers. Once these grooves have disappeared, the pad is in need of replacement.
Locate the cable pinch bolt, which attaches the brake cable to the body of the cantilever brake.
Use a 5mm Allen key and loosen the cable by turning the pinch bolt once counterclockwise.
Attach a 10mm open-end wrench to the back of the brake pad mounting post. Use the wrench to hold the mounting post in place while loosening the bolt at the front of the post with the 5mm Allen wrench.
Remove the brake pad from the mounting post. Repeat Steps 3 and 4 for the second brake pad.
Pull the end of the brake cable so that both brake arms are at 90 degrees, straight up and down.
Use the 5mm Allen key to tighten the pinch bolt back onto the cable.
Attach the first brake pad to one of the brake arm's mounting posts. Adjust the height of the pad so that the pad is level with the side of the wheel's rim.
Attach the 10mm open-end wrench to the back of the brake pad mounting post. Use the 5mm Allen key to tighten the mounting post bolt.
Repeat Steps 3 and 4 for the second cantilever brake pad.
Check that the pads are of equal height. If necessary, loosen the brake pad and adjust the height as needed.