The last time we worked on Baby Red, a six-speed 1995 coupe that sat neglected for three years, we covered how to replace the clutch hydraulics so the car can actually move under its own power. While the clutch is important, it’s the pedal in the middle that’s the most important. “Going” is always optional, but stopping is mandatory, and giving short shrift to your brakes is inviting property damage and personal injury. We’re big fans of big brakes around here, so there may come a time when we upgrade to an aftermarket system. For now, though, the goal is to get the car back on the road, so we went with new factory-replacement components, including new rotors, calipers, pads and hoses.
We ordered new Lone Star calipers (including heavy-duty fronts) through Street Shop, as well as rotors (including slotted fronts) and Wilwood braided stainless lines to replace the original rubber hoses that carried brake fluid from the steel hard lines on the frame to the calipers. The Wilwood line kit was accidentally ordered with the wrong adapters to change over from rubber hoses to braided steel, but with the correct Wilwood adapter part number we purchased a pair from Summit Racing.
For those unfamiliar with C4 calipers, the calipers are not simply bolted to the spindle like C2/3 and C5 brakes; both the front and rear calipers are mounted to a bracket. In the case of the front brakes, late C4 calipers are held in place at the top by tabs on the brake pad and at the bottom by a crosspin that’s held in place with a circlip (C-clip). To remove the caliper, pry off the circlip, drift out the crosspin, then pull the bottom of the caliper rearward until the top can be removed from its bracket (1984-’87 C4s have a different mounting system that uses a self-locking bolt up top). Very simple, and for just doing a pad swap, very fast. The bracket, however, will have to come off in order to remove the rotor, which means removing its two mounting bolts, which are torqued into place at some 137 ft-lb. Some of you may not need a breaker bar for that, but most of us do.
The rear caliper, likewise, sits on an anchor bracket (torqued to 70 ft-lb) to which the caliper is mounted with two guide pins. It also contains the parking brake mechanism, which you will want to take the tension off of before turning your attention to the rear calipers. Even with the slack this creates, removing the parking brake cable from the caliper-mounted lever is a challenge. We resorted to removing the tensioning spring from the lever with a short pry bar (an indispensable tool for this job), but make sure to use something like a shop rag over the spring to keep it from getting lost or injuring you when it finally lets go. The same pry bar makes short work of reconnecting the cable to the parking brake lever once the caliper is back in place.
Another indispensable tool is a set of flare nut wrenches that are designed to work with nuts mounted on the end of a tube, such as the frame-mounted steel brake lines. Essentially a reinforced box-end wrench with just enough material removed to let the wrench slip over the tube on which the nut to be turned rides, it lets you almost completely encircle the nut, decreasing the likelihood of damaging the nut during removal. Since brake systems aren’t routinely disassembled, the odds are good the nuts on the brake line have probably been there a while and won’t want to come off. Relying on an open-ended wrench is likely to round the nut off, which is a major problem if it happens on the frame-mounted hard line, so flare nut wrenches are cheap insurance.
Since you’ll be opening up the hydraulics, be prepared that you’re going to lose some brake fluid in the process. All the usual warnings about handling brake fluid and keeping it away from paint still apply, and the wise mechanic will keep an eye on the fluid level in the master cylinder anytime fluid is dripping, as letting it get too low will result in additional air getting into the system and a longer bleeding process. This is especially important on C4s, since they have antilock brakes, and we’re not wild about trying to bleed the ABS box. Better to keep an eye on it and keep it above minimum level.
Any caliper swap is going to involve disconnecting and reconnecting the brake hoses. Converting to braided steel lines also requires installing an AN adapter onto the frame-mounted hard lines, as well as installing a banjo fitting on the back of the caliper and orienting it in the direction that allows the most freedom of movement for the brake line. Once everything is together, bleed the new calipers, starting at the rear driver-side, then rear passenger-side, front driver-side and finally the front passenger-side. As with the clutch hydraulics, DOT 3 fluid is required and we used Wilwood’s 570; AMSOIL would be another excellent choice. Once you’re sure it’s fully bled, “burn in” the new pads by making a series of stops, gradually increasing the speed at which you begin braking, and you’re done.
1. Would you trust your life to this? Me neither. We’re replacing everything this side of the frame-mounted hard lines.
2. Since we were changing both the caliper and rotor, we went ahead and removed the caliper and bracket as a unit. This requires removing the upper and lower mounting bolts, which are torqued into place at well over 100 ft-lb, so spray them with penetrating oil and get ready for a workout.
3. Thanks to the years Baby Red sat outside without moving, one front rotor was frozen in place even after we sprayed it with some PB Blaster and gave it time to work its magic. We resorted to using Motivator, my favorite short-handled sledge, to knock the rotor loose as gently as possible.
4. The Wilwood braided steel line kit comes with the lines, AN adapter fittings and clips to hold them in place, as well as banjo fittings and the required copper crush washers. Braided steel lines are said to give a firmer pedal feel, as they don’t “give” the way rubber hoses do ... but mostly they’re just tougher.
5. Both the front and rear brake hard lines connect to the rubber hoses in similar fashion: the steel hard line has a male AN fitting that screws into the crimped-on fitting at the end of the hose, and a flat clip holds the rubber hose end in place in its bracket.
6. The first order of business is to release the rubber hose from the bracket by removing the metal clip that holds it in place. We used a small pry bar as a lever to pry it out. Take a good look at the crimped-on fitting on the rubber hose and notice how little material there is for a wrench to get purchase on—you don’t get many chances to get this right without rounding it off.
7. We used flare nut wrenches on both the rubber hose fitting and the AN fitting on the hard line. Even though the clip has been removed, we found it easier to separate the two by keeping the fitting on the rubber hose seated in its bracket. Be prepared for fluid to leak out as soon as the two start to come apart.
8. This is the AN adapter fitting. The hard line screws into the female end, which protrudes downward through the horizontal bracket for the front brakes (the rear bracket is vertical, and the female side goes toward the front of the car), and the braided steel line screws onto the male AN fitting. It’s held in place by the same type of flat clip as the factory hose. We installed the new ones that came with the kit.
9. With the rubber hose freed, you can now completely remove the caliper, which includes unbolting the other end of the rubber hose from the back of the caliper. Make sure to save the brake hose fitting bolt; it will go through the banjo fitting into the new caliper. The calipers and banjo fittings each came with different thickness crush washers. We compared them to the holes in the brake hose fitting bolt and the channel inside the banjo fitting and chose the thicker ones; one goes on each side of the banjo.
10. Screw one end of the braided steel line onto the banjo fitting on the back of the caliper, and the other end onto the AN fitting that fits in the bracket where the brake hose used to sit. Once it’s seated, secure the AN fitting in place with the flat metal clip. The clip fits into a groove that goes around the outside of the AN fitting. It’s a bit of a tight fit to get it into place, so we tapped it in with a hammer. This is the rear brake line, which is assembled the same as the front.
11. We sprayed down our slotted front rotors with O’Reilly brake cleaner, slid them into place and then bolted the caliper mounting bracket back on, torqueing it to the required 137 ft-lb.
12. The brake pads go in with the tab pointing upward, and are held in place by fingers on the rear of each pad that snap into place in the two large mounting holes on either side of the caliper. Use a C-clamp to compress the brake pistons enough so the brake pads will fit over the rotor.
13. Insert the tabs on the upper end of the brake pads into their recesses in the caliper bracket then rotate the bottom of the caliper into place and secure it in the bracket with this cross pin. The end of the pin is secured with a circlip (C-clip) that can be pried off with a narrow screwdriver, and will probably need to be tapped gently into place with a hammer. This will be much easier if you insert the pin from through the back of the caliper mounting bracket, as shown here.
14. Before tearing into the rear calipers, we started by taking pressure off the parking brake cable. Removing the driver’s seat (or perhaps just the cushion) will make it possible to access this cover, which will have to be unscrewed and removed so we can get to the mechanism beneath it.
15. With the cover off, disable the parking brake automatic adjuster (creating slack in the parking brake cable) by lifting up the drive pawl with a small hook and holding it in place with something like a jeweler’s screwdriver inserted through a hole in the anchor plate. This is harder to describe than to do; once you can see the parts, it’s actually quite simple. When the brake job is done, remove the screwdriver and pull and release the e-brake handle several times to reset the mechanism.
16. The hardest part of removing the rear caliper—which, like the front, unbolts along with its anchor bracket—is disconnecting the parking brake cable from the spring-actuated parking brake lever. We pried the spring off first and then worked the cable off, and reinstalled it with a small pry bar.
17. The sheathing of the parking brake cable snaps into place in a bracket on the side of the caliper. In this photo, you can see the little fingers that hold the cable in place, each one of which has to be compressed in order to remove the cable from its bracket. We used the end of a screwdriver to push each one down as we rocked the cable in its bracket to keep the fingers compressed.
18. The caliper is mounted to its anchor bracket with two guide pins, which slide into place in the bracket, and which are sealed up with a rubber boot that should be carefully peeled back during removal and equally carefully snapped back into place upon reassembly.
19. The rear brake pads are spring loaded. As you look down into the caliper window (the opposite of the way it’s shown here), the “top” side of the pad has an ear on each side that mounts into recesses in the caliper, while the bottom tab has the two-sided spring on it. We found it was easier to seat the ears in place first, and then slide the spring side down its slot visible in this photo until it’s fully seated. Bleed ’em, burn ’em in and you’re ready to go take a drive.
Photography by Jeremy D. Clough