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| C4 Corvette Chassis |
| 1957 Corvette RestoMod Project - Page 14 C4 Rear Brakes Rebuild Corvette C4 rear brakes have an integrated E-brake mechanism. To restore and rebuild my brakes, I decided to replace all parts that have worn out, or will wear out. Several rubber pieces need replacing, and other mechanical components will be either replaced or media blasted and painted. Once you have disassembled the brakes, it is not difficult to restore and rebuild them - despite the fact that they look very complicated. Do only one caliper at a time! Use the other one for reference on how nuts, bolts, and other parts are fastened. Chapter 7 of my book covers this part of my project, and can be purchased as an E-chapter by clicking HERE. |
| Above is caliper repair kit #60196 from AutoZone. It is a full repair kit for one rear caliper - and it comes with the best instructions I have ever seen. That's because the company that makes it also makes the C4 brakes - PBR Australia. That's right, Corvette brakes are made "down under"! |
| After sandblasting both calipers, they were treated to high-temp paint made by G2 Systems from Eastwood. I wanted them black to match my car's motif, and because the 1996 Grand Sport had black calipers - not red. The G2 System comes with paint, catalyst, brush, and brake cleaner. Make sure the calipers are cleaned well before painting. |
| The first replacement is the caliper bore seal. The seal prevents brake fluid from bypassing the piston. It is removed by using a pick or small screwdriver. BE CAREFUL! Don't damage the bore in any way. The piston and bore have very tight tolerances, so scratches or other damage will possibly cause leaking or brake failure. The new seal from the kit above needs to be greased with the supplied fluid. Make sure the seal is not twisted in the bore groove. Also grease the bore completely - but make sure you have cleaned it thoroughly with brake cleaner first. |
| Pictured left is the Clamp Rod - Reaction Plate component being removed from the Collar Assembly. It slips out past the inner and outer boots of the collar. At right, is the collar being disassembled. The collar retainers hold the inner (left) and outer (right) boots, as well as the push rod (top right) and Actuating Collar (held). |
| Once new inner and outer boots are installed in the new retainer plates from the kit, the collar is re-assembled. A new Preload Spring is used (top left) - and must be installed correctly. Pictured top right is the assembled collar. Make sure the push rod is seated correctly in the groove of the actuating collar, then pinch the ends together with needle-nose pliers and tap the retainer tabs down. The collar assembly should be tight with no loose parts. The kit also includes a new Compliance Bushing for the clamp rod (not pictured). Lubricate all components with the supplied grease and slide the clamp rod back in to the collar assembly. |
| The Collar Springs are next. They insert from the back of the caliper - but don't install the E-brake lever yet (right)! The springs are installed the same way they were removed - with needle nose pliers. It is important that they attach to the collar on the second coil (far right). |
| After cleaning the caliper piston, lubricate it thoroughly and place it at the bore opening. It should be difficult to push the piston in to the bore - that's okay. Set a small block of wood on top of the piston and gently tap it in to the bore. I have a small shop press that accomplished this step without all the pounding. But make sure you don't Bubba the piston too far - only so the top of the piston is flush with the bore opening! Once the piston is seated correctly, insert the clamp rod with collar assembly in to the piston. Then seat the inner boot lip in to the bore groove. |
| Remove the bleeder screw and blow it out with compressed air (at left). The kit has a new dust cap for the bleeder. Also, I strongly suggest you buy new brake hoses. The hose is attached using a banjo bolt and two new copper washers - one inside and one outside the bolt. Brake hoses are under tremendous hydraulic pressure and any imperfection can result in catastrophic brake failure. |
| The E-brake Lever uses a special bolt that fastens the lever to the caliper. The bolt is retained in the lever with a sprag washer, seen at right. Lubricate the new dust boot and lever bolt liberally with caliper lube (Permatex is what I used). The sprag washer is installed with the teeth facing upward. I used a 12mm socket to evenly push the washer down the bolt shaft and snugly to the lever. Also note in the right photo that the lever has a notch that must contact the push rod from the collar assembly. When the E-brake is engaged, the lever moves the push rod inward. This also pushes the collar and actuating plate against the inner brake pad. As more E-brake is applied, the caliper moves along the guide pins until the outer pad also clamps down on the rotor. |
| New Guide Pin boots from the kit are lubed and installed over the pins and the pins are lubricated as well. Then insert the guide pins in to the caliper bracket housings. Next, the Pivot Pin is fastened to the caliper with the Abutment Bracket as seen at left. Use a metric hex-key size HW6 to secure the pivot pin bolt. The lower guide pin is fastened to the caliper bracket by a regular hex head bolt. |
| Install the brake pad making sure the inner pad contains the wear indicator tab. The caliper bracket fits over the pads with each end of the pad backing plate fitted in to the notches of the bracket. Before installing the bracket though, you need to first insert the guide pins in to the bracket, as described below. |
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1957 Corvette RestoMod