Corvette Caliper Rebuild/Reassembly
Article by Mark Trotta
After painting the brake calipers, the final phase of the rebuild was reassembly. Caliper rebuild kits include piston seals, caliper seals, dust boots and O-rings. Front and rear kits are different, and are available from several suppliers.
Read: Spray Paint Brake Calipers
Slightly stretching the seal, install it in the groove which is closest to the flat end of the piston. The lip on the seal faces the large end of the piston.
The hardest part of the reassembly is getting the pistons with the new seals back into their bores. The edges of the lip seals need to be pushed in, or compressed, like rings on a pistons. There are several ways to do this.
Caliper Piston Installation
If you're using the factory-style lip-seals, the best way to install the pistons back into their bores is to use a piston installation tool, shown above. After installing the seal, you push the piston through the inside of the tool and into the bore of the caliper.
If you're using the O-ring style seals, getting the pistons back into their bores is easier. You can use a blunt flat-blade screwdriver (carefully) or a small plastic flexible card to push in. Care must be taken not to score the inside surface of the bore or scratch off any of the pistons anodizing, or tear or puncture the edge of the seal.
Buy the installation tool and the hardest part of Corvette caliper rebuilding becomes easy. The pair sells for about $25.
I poured a small amount of clean brake fluid into the bores and wiped brake fluid around the piston, seal, and bores with a finger before installing. Lubricate everything. If you're using the lip-style seal, remember to place the spring in the bottom of the piston bore first. Using springs on the O-ring style is optional.
Once installed, hold the top of the piston with a finger or two, grab a metal-ringed piston seal, place it on top and gently tap it down. There is a specialty tool made for this, but a large socket and a hammer work fine. I used a 38mm socket.
Gently tap the metal-ringed piston seal into the bore. The metal gasket should be evenly seated around the bore, with no portion of it higher than another. Double-check by running your finger around the circumference.
After installing the caliper half O-rings, place the inboard half onto the outboard half and install the two bridge bolts. Torque them with a 13/16" socket.
Re-install the brake pads back into the caliper. Apply a little synthetic grease on the forward surfaces where the brake pads ride in. Install the cotter pin, which goes on the inboard side of the caliper.
Caliper mounting bolts get torqued to 70 lb-ft.
Installing Corvette Calipers
Carefully mount the assembled caliper over the edge of the brake rotor. There are several methods you can use here that will achieve the same result. You can separate the pads with 1-5/16" thick wood block spacer, which will pop out when caliper is placed over disc. This approach eliminates possible damage. Or use a putty knife or speciality clips, which are also effective. Reinstall bolts and tighten.
Inspect the rubber brake hoses. If you're unsure as to their age and condition, replace them. Use a new inlet copper washer when installing the new brake hose (some restorers use two washers). Torque brake hose to caliper at 22 lb/ft.
Read: How To Make Brake Lines
Once done, bleed the entire brake system. Although it takes longer, I prefer gravity-bleeding.
TIP: If you fill the calipers with brake fluid before you hook up the brake lines, it will shorten the time needed to bleed the system. You can use a small squeeze tube of brake fluid and a flexible hose. Squeeze the fluid into the line until it comes out the bleeder. For the rear calipers, squeeze fluid in one bleeder until it comes out the other bleeder.