Many of the older bikes that have been sitting for a while tend to have dragging brake calipers. This can be caused by corrosion in the hydraulic system, deteriorated inner hoses, or rusted mounting collars.

Brake fluid should be flushed and changed on regular intervals, and especially when not used for long periods of time. Brake fluid attracts moisture that sweats through the metal fittings or metal portions of the hose.

This moisture can do one of two things; one is create air bubbles in the system when the moisture evaporates from use, and two begins a corrosion process which attacks the bare steel and aluminum components within the system.

The most prone area to corrode is the base of the groove where the brake piston caliper seals seat. Corrosion under the seals increases the pressure of the seals on the pistons causing them to not move freely. If the brake lever seems stiff, or does not seem to grab without a lot of pressure, a brake caliper rebuild would be the corrective action for this problem.

The other problem that occurs is dragging when the brakes are not applied. This is most often caused by rusted mounting slide collars not allowing the brake caliper to return to its neutral position. A sign of this is seeing excessive wear on the inner side of the disc rotor. Excessive wear is usually grooving, or a galled shiney appearance. The hydraulic pressure of the pistons moves the caliper on the mounting collar so the inner brake pad makes contact with the rotor, but is not allowed to release. If the rubber boots surrounding the collars or slide pin mounting bolt are torn or missing, there is a good possibility that moisture has corroded the sliding surfaces, and should be repaired.

You can use a cylindrical wire brush to clean the hole(s) inside the caliper, and a wire wheel to clean the O.D. of the collar. We use a high temp silicon lubricant like Syl-Glide (NAPA) to lubricate the collar and rubber boots.