Brake Caliper Rebuild - Be Kind to Your Calipers

The pistons are steel and should be reusable unless something really wrong has happened to your calipers. Here, ours are scrubbed with a Scotch Brite pad in the parts washer to remove the wear ring that had developed where the end of the piston was exposed to the elements.

On the left is a freshly scrubbed and polished caliper piston. On the right is what it looked like before cleaning. It’s important to get the pistons clean so that they will slide inside the seal without sticking. If they don’t, the seal can hold the pistons out, which keeps the brake pads from retracting and causes brake drag.

These are the backing plates that the edges of the brake pad slide along. They not only allow easy movement of the pads as they’re pushed out by the pistons, they also keep the edges of the backing plates from digging into the aluminum caliper. Remove them for cleaning and so that you can inspect the caliper material underneath.

On the bottom is one backing plate just as it came out of the caliper, while the one on the top is what it should look like after it has been cleaned. Again, it’s important that these are as clean and as smooth as possible so that the pads will be able to slide out—and back in—without snagging or experiencing drag.

Now that the caliper has been completely stripped, wash it down with brake cleaner and hose it with dry, clean air. Make sure that any crossover tubes are clear of debris and you don’t leave any cleaning fluids behind inside the caliper that can contaminate the brake fluid when the calipers are reinstalled.

Reinstalling the O-rings dry can cause them to rip the first time the brakes are applied. Lubricate them with some fresh brake fluid.

Now you can install the O-rings back into their grooves in the piston bores. Be careful to make sure they are fully seated and don’t get twisted when reinstalling them.

The freshly cleaned pistons will be less likely to get hung on the O-ring (and will be easier to slide in place) if you also lubricate it with fresh brake fluid.

The brake bleeders are exposed to the elements and you’ll often find that they are clogged with debris. If you can’t blow air through them, try reaming out the gunk with a small drill bit.

Follow that up with a blast of brake cleaning fluid and then dry shop air to make sure they are completely clean and obstruction free.

A bit of Teflon sealer on the fluid inlet fitting will help prevent leaks and help keep it from galling to the caliper so you can get it out again on the next rebuild.

Finally, you can complete reassembly of the caliper and reinstall it on your race car confident that it’s ready to provide dependable service for another season of racing. CT