Slide Pins and Uneven Brake Pad Wear
Uneven brake pad wear is very common with floating caliper brake systems. This is because the slide pins can stick inside the sleeves they fit into.
Sticking slide pins in the sleeve of a floating caliper become frozen from environmental contamination. Sometimes sticking slide pins can be very difficult to remove. Replacement pins and sleeves may be required to repair this condition. Never grind off the gold or chrome finish. This leaves the pin susceptible to pitting and excessive wear. Many of these systems use a rubber bushing or O-ring around the pin to locate and fit the pin snug in its bore. Always use the correct lubricant. Avoid lubricants that swell rubber parts causing the bushings to stick in their bores.
Floating and sliding calipers are not mounted directly to the steering knuckle or suspension component. A floating caliper rides or floats on a mount that is integrated or bolted to the knuckle. These calipers typically contain a single piston that moves the inboard pad into contact with the brake rotor. After the inboard pad contacts the rotor, the caliper slides or pulls the outboard pad into contact with the other side of the rotor. These two pads squeeze the rotor. The friction between the two pads causes the vehicle to stop. If the slide pins are frozen, the outboard pad doesn't slide into contact with it's side of the rotor. This means that the inside pad is doing most if not all of the braking. Not Good.
A sliding caliper slides on rails or ways on the mounting bracket. These rails can become rusty or corroded, causing the caliper to bind instead of slide. This binding results in premature inboard pad wear. Remove the rust and use the proper lubricant on the rail the pads ride on. Worn or loose slide pins or caliper slides result in caliper twist and lost brake performance.
Always use the proper lubricant when working with brakes. Rubber components require a high temperature silicone or synthetic lubricant specially designed for these rubber parts. A good high temperature graphite or synthetic lubricant designed for metal to metal contact will work great for any metal to metal components like the slides on sliding calipers.