Rebuilding your brake calipers...
Rebuilding your brake calipers before the start of each racing season—especially if you race on dirt—will not only help improve the useful life of those calipers, but can also increase performance on the track.
Nothing lasts forever—except for maybe American Idol, which just won't seem to die—and this is especially true in racing. But proper care and feeding of your race car's brakes can help them last longer and perform better. Thus, helping you stretch your racing budget and improve your performance on the racetrack.
Most racers regularly work on their braking system, including bleeding and/or flushing the brake fluid, inspecting the rotors for cracks or warping, and deglazing or simply replacing brake pads. But one area that shouldn't be overlooked is the calipers themselves.
Most brake calipers, especially performance-oriented units from reputable manufacturers, are deceptively simple pieces of technology. Essentially, they are a cavity capable of transmitting the pressure of the brake fluid to pistons that squeeze the brake pads against the rotors. And as such, there really isn't a lot that can go wrong with a caliper as long as it's well-built to begin with.
However, rebuilding your calipers before the start of a new racing season is definitely a good idea, especially if you race on dirt. There's a lot of grit, sand, oil dry, and all types of stuff blown around underneath a race car and if it accumulates between the piston and seal it can cause fluid leaks, sticking calipers—which will overheat the brakes and harm acceleration—and premature brake failure.
Rebuilding your calipers is a relatively easy job that can be done by practically anyone with simple handtools. We would recommend having a set of new piston seals on hand but they may not be needed. Following are a few tips for rebuilding your calipers for maximum performance season after season and long brake life. The Dirt Late Model team we worked with uses Wilwood brakes, but the same concepts will work with any brand. You may also notice that the Wilwood Dynalite calipers in the photos are a few seasons old and show signs of use, but simply a testament to the value of using quality products and taking care of them.
Begin by pulling all four...
Begin by pulling all four calipers off the car and knocking off any loose dirt or grime. Next, remove any hardware so you can pull the pad out.
After getting everything out...
After getting everything out of the way, you can pull the pads out. If they’re jammed in place, that’s a sign that you may have more serious problems to look at. These pads have plenty of material left. After scuffing them up a bit to remove any glazing from the last race, they will go right back in.
Now begin the tricky process...
Now begin the tricky process of getting the caliper pistons out of their cylinders. The pistons move in and out to press the pads against the rotor. One way to do it is to use deep-reach Vise-Grips like these to hold the other pistons in position and then place an air chuck against the brake fluid inlet fitting and blowing pressurized air into the caliper. The air pressure should blow the piston out of the bore.
With the piston out, you’ll...
With the piston out, you’ll have to gently hold it in place so that the caliper will hold air pressure as you blow out the other pistons one at a time. This is easily the most aggravating part of the entire process.
After all of the pistons are...
After all of the pistons are out of the caliper, gently remove the rubber piston seals which should be inside a ring in the caliper’s piston bore. Inspect each rubber-like ring. If it’s hard, distorted, torn, or showing other signs of wear, replace it.
Most performance brake manufacturers...
Most performance brake manufacturers sell a caliper rebuild kit like this one from Wilwood. It cost less than $20, so it was nice to have a few spare O-rings on hand in case we needed to replace one.