Rear disc brake conversion on a 1967 Mustang
Currie's rear disc brake conversion kit provides lots of “whoa” in a small package.
Frank Bohanan - August 01, 2011 09:00 AM
1 After removing all of the original brake components, axles, and so on, be sure to inspect for any damage and clean the area up before installing new axle seals at each end. Be sure to use the proper size seal driver and just tap it in until it seats correctly.
2 Always use new bearings whenever the axles are removed. They’re designed to only be installed once and MUST be changed before the axles are put back in. You may also need to change the wheel studs to ones with a raised shoulder for the rotor to contact instead of hitting the threads. After changing the studs (if necessary) and dropping the caliper mounting plate onto the flange, use the proper press and technique to install the new bearing on the axle. Use threadlocker between the bearing and axle for extra insurance.
3 Install the axle into the housing and secure it with the T-bolts. Make sure the caliper mounting bracket is properly “clocked”/indexed to ensure there is no interference with the spring, etc. The mounting plate must sit flat with the caliper mounting tabs facing inward. Notice the flat shoulder on the wheel studs that will locate the rotor (versus the threads). The nuts that secure the mounting plate are tightened one at a time by rotating the axle so that the access hole lines up with each nut so it can be tightened.
4 Once the bracket is securely mounted, test fit the caliper by loosening the bolts for the mounting tabs to ensure the caliper mounting bolts line up properly. Hand tighten the bolts for the tabs with the caliper mounting bolts in place to maintain the proper alignment. Remove the caliper and securely tighten the mounting tab bolts while making sure they don’t move out of position. We also painted the hub to help prevent rust formation.
5 The installation of the correct centering ring is critical to achieving optimum brake performance with minimal vibration or pulsation, etc. While the shoulders on the studs do a decent job of locating the rotor, use of a centering ring ensures the rotor and the axle are on the same centerline with minimal possible movement. Keep the lip towards the axle.
6 As you can see when the rotor is installed, there is still some space around the studs but there is virtually no clearance between the centering ring and the rotor or the axle hub. This ensures the best possible concentricity to maximize performance and durability.
7 Use one lug nut to keep the rotor flat against the axle before you install the caliper over it. Tighten the caliper mounting bolts and spin the rotor to make sure it turns freely and has no wobble or other problems. Clean the rotor surfaces with brake cleaner.
8 Attach the brake hoses to the rear of the calipers using the correct bolts and copper washers. Hold the hose at the proper orientation with one wrench while you tighten the bolt with the other. Be careful not to overtighten the bolt or crush the washers too much. Line up the new, flexible Currie hose with the original hard brake line while making sure it is routed away from any moving parts and there is enough slack to allow for its own slight movement. Mark a spot on the axle tube for where the hose mounting tab will go.
9 Scrape away the paint at the chosen mounting position and then tack weld the hose mounting tabs to the axle tube. Verify the location is correct in terms of clearance with other parts and allowing the hose to have a bit of slack. Once all of this has been verified do the final welding and painting of the tabs and the axle tube.
10 Cut and re-flare the factory hard brake line or, bend up a new one as needed to mate up with the Currie hose and secure the two together along with the appropriate retaining clip.
11 It will be necessary to do some custom tube fabrication to make the factory hard lines mate up with the Currie hoses. The hose/hard line interface on the other side of the axle tube took a little extra care since there was such a short distance from the Y-block to the hose end. A little careful bending took care of things so that it went together just as easily as the other side. Use the correct flaring tools and tube benders to achieve the required shapes. Always be sure to use double flares for proper sealing. (Check out the February 2011 Auto Enthusiast, A Flaring Situation, for more on flaring hard lines.)
12 Attach the ends of the parking brake cables to the calipers. Currie provides a Lokar-style set of cut-to-fit parking brake cables that are far superior to application-specific OEM cables, plus they are available with the correct ends for the now different era components.
13 The other end of the parking brake cables mount in the factory location with simple screw-on nuts. You just route and cut them as it necessary for the application.
14 Thread the parking brake cables through the stop on the caliper and into the cable sheath you attached earlier. Note how the ball-shaped end of the cable sits in the pocket in the slotted tab on the caliper. Grease the cable lightly (just a thin, almost invisible skim coating) with a tacky, waterproof marine grease before you thread it through the sheath.
15 The ends of the parking brake cables get cut to the appropriate length and get joined using the gold connection block provided. You simply insert the cable ends into the block and tighten the set screws to secure it. Be sure to leave enough length for adjustments.
16 The finished setup looks very clean, very factory. The low profile calipers will clear factory size wheels with no trouble, yet you have better braking and easy pad access.
17 In some situations it may be advisable to install a residual pressure valve in the brake line. Basically, this maintains a small amount of pressure in the brake line (two pounds here; other ratings are available) to help improve brake response and minimize the effects of axle free play. The residual check valve gets installed after the master cylinder in the appropriate brake circuit. Simply cut the brake line and re-flare it on both sides and then install the check valve by tightening the new flare nuts you put on both sides BEFORE you did the flare job. Bleed the whole system. Now is also a great time to replace the brake fluid. With that, you’re good to go – and stop – more safely. ￼ For Your Information:
If there’s one area where newer cars have a significant performance advantage over older cars, it’s braking. They not only stop in a shorter distance, but with greater stability and less fade, etc., during repeated use.
This advantage is even greater when technologies such as anti-lock brakes and electronic brake force distribution and so on are also factored in. Even without these electronic nannies, much of the gains are due to superior design, materials, and manufacturing.
There are plenty of aftermarket brake kits available, but not all of them are particularly well suited for performance street use on an older vehicle. Sometimes this has to do with the components being designed more for racing use and less for dealing with harsh weather, dirt, and other problems a street car sees that a racer generally doesn’t. Another issue is the size of the components. Many kits require you go to a larger wheel size to clear their brakes. This may not be desirable if you want to keep the stock look by using factory-sized wheels. So how do you get a significant improvement in braking performance while still being able to retain the factory wheels sizes? Use an OEM-style brake from a later year.
Currie Enterprises has developed several kits which use the rear disc brake hardware from mid-’90s Ford Thunderbirds, among other applications. These brakes are an OEM part, so they are more than capable of surviving in the real world. Yet they are still able to handle occasional track use such as track day, time attack, or HPDE (High Performance Driving Event) duty with little more than maybe a pad change and some better brake fluid. They are a very light, compact design with an integral parking brake and an 11-inch rotor. They’ll fit in most factory wheels with room to spare and they are an OEM part, so they will still have more of a factory look compared to more radically- styled aftermarket kits. Another bonus is that they’re relatively less expensive, plus they use a very easily found pad size with many compound options. Currie can set you up with a full kit, including the parking brake cables, that will be a huge improvement over drums. It will be quiet, reliable, and durable while still being capable of doing some track duty.
In the following photos we’ve shown the installation of one of the Currie kits on a ’67 Fairlane. The steps are basically the same regardless of vehicle, so it will work well with your early Mustang. We didn’t show the removal of the factory brakes, since that is pretty straightforward, yet it is the most vehicle-specific part of the conversion. Use the factory service manual if you’re a newbie or get a more experienced friend to help if you’re new to this type of thing. You’ll probably want someone else around anyway when it comes time to bleed the brakes.
Other than a little welding and some tube fabrication, there’s really nothing tricky about installing the Currie kit. Depending upon your experience and the equipment you have available, it could take as little as an afternoon or perhaps a day to install the system. The first time you use the new brakes you’ll realize it was time very well spent.