| C4 Corvette Chassis |
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| 1957 Corvette RestoMod Project - Page 13 C4 Rear Brakes Disassembly Rear brakes in the C4 have the emergency (or parking) brake mechanism incorporated into them. Unlike other vehicles though, the E-brake is not a drum and shoe setup. In those types of E-brakes, the rotor hat is larger and contains small brake shoes that press out against the inside wall of the rotor hat. For the C4, the E-brake employs a lever and spring setup. When the E-brake is applied, the lever makes the pushrod, collar, and clamp rod move outward which causes the caliper to move inward. This "mechanical" function then forces the pads to contact the rotor and clamp it so the vehicle does not move. It's a pretty cool setup, so let's explore how to take it apart and restore the pieces. |
| Pictured left is the right rear caliper assembly. The E-brake cable is held by a bracket (lower right) and the cable ends at the lever (lower left). The caliper bracket contains lubricated slide pins and the calipers are single piston design. Since most of the braking happens at the front of every vehicle, the one piston will be plenty to stop my lightweight little '57 Corvette. The caliper and caliper bracket are attached by use of the lubricated slide pins. These pins allow the caliper to move, or "slide" so the outside pad can contact the rotor. This is a typical passenger car caliper setup. You can also see that I have threaded the caliper bracket bolts into their proper holes to ensure that I won't lose them before assembly. |
| The entire brake assembly needs to be taken apart, marked for any special location, and restored. The slide pin dust boots will be replaced, the E-brake bracket, lever, and spring sandblasted and painted, as well as, the caliper bracket itself. The caliper will be rebuilt too with a new seal and boot. And a new set of brake pads will round out the restoration. First, let's review the disassembly... |
| At right, you can see the E-brake cable and how to remove it from the lever. You don't have to remove the spring first, just use a finger to slightly bend the cable so the eyelet can slip off the lever. Also notice the dust cap over the bleeder screw. Just left of the bleeder is the brake hose banjo bolt. The entry of brake fluid to the caliper happens at this opening. If you are not going to refurbish the caliper, make sure you cover the hole with tape, or insert a rubber stopper here. This prevents debris or other fluids from entering the caliper. You can seriously damage your caliper if this happens. I'm going to dismantle the caliper and sandblast it for new paint, so I did not need to be so careful. |
| In the picture at left, you can see how the E-brake works. At lower left is the lever fulcrum with a small pushrod that extends through the caliper housing and contacts the piston collar (shiny silver). When the E-brake is applied, the collar and caliper piston are "mechanically" pushed out so the inner pad can contact the rotor. As more force is applied, the caliper moves along its slide pins (far left and far right) until the outer pad also contacts the rotor. With the right calibration and force, the caliper piston is pushed into place with a firm grip on the rotor - the result is the car's rear brakes are locked and secure. When the E-brake is released, the two small springs on either side of the piston collar retract the piston and relieve the pads from the rotor. Easy-peasy lemon squeasy! |
| After removal of the E-brake cable, I also unhooked the small collar springs - but left them in their holes for now. The brake hose was then removed and the bolt put back in the caliper to prevent brake fluid from trickling out (you can just as easily let it drain into a proper receptacle). Now you can remove the lever spring and lever. The spring has high tension so make sure you have a good grip with pliers. The lever bolt goes through the caliper with a nut on the top side. |
| Picture above-left is removal of the collar spring. Notice the spring slips over the collar's tab a couple of rings below the end. The pushrod can also be seen just to the right of the spring. Above-right is the removed E-brake lever. A dust boot covers the bolt end. |
| The caliper bracket, seen right, houses the slide pins and dust boots. The pins are hollow to allow bolts to be fastened to them through the caliper. The bracket bolt at right is a standard metric head bolt, while the left one is a metric hex head bolt. A second hex head bolt holds the cable bracket from the bottom (next to the green tape). Not realizing that hex heads can be SAE or metric, I tried to use my SAE hex bit and basically stripped the bolt head - sheeesh! But after the clever use of a bench vise, the bolts were eventually removed. Don't worry about assembly though, RockAuto and your local parts retailer has replacements - or just go to a good hardware store. |
| With everything removed, including the piston collar and plunger, use compressed air to force out the caliper piston. Seen at left, make sure you have a block of wood or other soft material inserted opposite the piston before blowing it out. When it releases from the bore, it will come out with a lot of force. I used some old mechanics gloves here to cushion the piston when it rapidly exited the piston bore - and no, my hand was not inside the glove. Take extra caution to not scratch or damage the piston or bore. Tight tolerances are used by this hydraulic system. |
| The next time you see these brakes, all components will have been refurbished. Wrap the piston in a rag or paper towel and stuff paper towel in the piston bore too for protection. The calipers will be treated to high temperature black paint to accent the look I want for the car. |
1957 Corvette RestoMod