Slide Pins and Uneven Brake Pad Wear
Sticking slide pins results in uneven brake pad wear with floating caliper brake systems. They become frozen from environmental contamination and can be difficult to remove. Replacement pins and sleeves may be required to repair this condition. Never grind off the gold or chrome finish. It leaves the pin susceptible to pitting and excessive wear. Most have 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. They ride or float on the 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 its 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. High-temperature graphite or synthetic lubricant designed for metal to metal contact works great for any metal to metal components like the slides on sliding calipers.