The 1975 Chevrolet Corvette has four-wheel power disc brakes. The calipers on all four wheels have four pistons with two pistons on each side of the caliper. Rebuilding the calipers and is a straightforward project but careful inspection should be made of the pistons and the piston bores inside the caliper body. If the pistons or bores are pitted, then the caliper should be replaced. Rebuilt calipers are available at a reasonable price.
Tools Used: Jack, Jack stands, Ratchet and socket set, Wrench set, Brake cleaner, Pick set, Caliper rebuild kit, Brake fluid, Small slotted screwdriver, Torque wrench
Rebuild the Caliper
Park the Corvette on a level, paved surface and set the parking brake. Loosen the lug nuts on the wheel where you want to rebuild the caliper. Raise that part of the Corvette, either the front or the rear, and support the vehicle with jack stands. Remove the lug nuts and pull the wheel off the Corvette.
Disconnect the brake line from the caliper. For front brakes, remove the flexible brake hose from the metal line. Leave the hose attached to the caliper. For rear calipers, remove the brake line from the caliper. You will need two wrenches for front brakes -- one to loosen the flexible hose and one to hold the metal line. Only one wrench is needed for the rear brakes. Other than this, the removal and rebuild procedure is the same.
Use needle-nose pliers to remove the cotter pin from the brake-pad retaining pin. Slide out the pin and pull the brake pads out of the caliper. Use a ratchet and socket to remove the two caliper retaining bolts and remove the caliper.
Use a ratchet and socket to remove the two caliper assembly bolts. These bolts hold the two caliper halves together. Pull the caliper halves apart. Take note of the two O-rings in the bolt holes.
Thoroughly clean the caliper halves with spray brake cleaner. Use a small pick to carefully remove the two O-rings. Push the pistons of each caliper all the way into their bores. Use the small pick to pry the piston boots out of the caliper halves. Note that they have a wire spring built into them.
Pull the boots off the groove that holds the inside of the boot to the piston. It is OK if the piston comes out when you do this. If it doesn't, pull it out now. Remove the spring that sits behind the piston. Remove all the boots, pistons and springs. Make sure to arrange the pistons so you can put them back into the same bores from which they were removed.
Use the pick to carefully pry the piston seal out of its groove. Note the way the seal lip faces the inside of the caliper bore. Spray the pistons clean with brake cleaner and allow them to dry. Slide new seals onto the pistons. Lubricate them with clean brake fluid. Install the springs and pistons into their bores. The lip on the seal will try to hang up on the caliper bore -- use a small, slotted screwdriver to carefully and gently work around the piston seal and move the lip into the bore. You will only have to move the lip a little bit to get it in.
Push the inside diameter of the new boot over the groove in the piston. Push the outside diameter of the boot into the notch in the caliper. Repeat for all of the pistons.
Lubricate the new O-rings with brake fluid and place them in one of the caliper halves. Bring the two halves together. Lubricate the caliper bolts with brake fluid and install them into the caliper. Tighten the bolts as tight as you can with a ratchet and socket. Final torque will be applied after the caliper is installed.
Mount the caliper and install the mounting bolts. Use a torque wrench to torque the bolts to 70 foot-pounds. Torque the caliper half-bolts to 130 foot-pounds for front calipers and 60 foot-pounds for the rear. Install the brake pads, pad pin and cotter pin. Reconnect and tighten the brake hose.
Fill a dry 20-ounce water bottle one-third full with clean brake fluid. Use a wrench to open the bleeder screw on the inside half of the caliper. Attach a piece 3/16-inch clear plastic tubing to the bleeder screw and put the other end in the plastic bottle with the end submerged in the brake fluid. Make sure the brake master cylinder is full of brake fluid. Have an assistant push the brake pedal down three or four times. Air will be expelled from the caliper. Check the level of the master cylinder. Repeat this process until no air exits the caliper. Close and tighten the bleeder screw. Repeat this process for the outside bleeder screw.
Mount the wheel and install the lug nuts. Raise the Corvette and remove the jack stands. Lower the Corvette and tighten the lug nuts.
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