Reassembled Piston Here is the piston after clean up, reinstalled in the cylinder with dust boot installed. First the square seal is dipped in brake fluid and worked into it's slot. Then the piston is dipped in brake fluid and slid into the cylinder. Be sure to orient the flat at this point. Now you can squeeze the piston into the cylinder gently by using the 'C' clamp. Finally the dust boot is put on and the retaining ring slid over the dust boot to keep the boot on the piston and attached to the caliper. The orientation of the flat is done to move the center of force to the trailing edge of the brake pad. This counter acts the rotational force generated by the friction of the pad against the disk which pushes the leading edge of the brake pad against the disk and evens out the force across the pad when braking. If the piston was turned the other way, it would push primarily on the leading edge of the pad and the friction would try to lift the trailing edge off the rotating disk, causing uneven wear and inefficient application of force. |
