The Fox body Mustang originally came from the factory equipped with drum brakes in the rear (with the exception of the SVO and Cobra models). After replacing the main components for the rear drum brakes on this Fox body less than a year ago, the parts were already showing signs of wear and tear. Braking components are extremely important, and it’s crucial that every component involved is working to it’s highest capabilities. Knowing this, we needed to address these problems as soon as possible. We considered doing an overhaul on the current factory drums again, however after much time and thought, we didn’t want to wait another year and find ourselves stuck in the same situation.
Would you rather work on a more modern and simplified disc brake setup, or the complicated brakes above? Yep, we thought so, too.
Why Do Drum Brakes Get A Bad Reputation?
At the end of the day, it’s a great investment performance-wise, but an even greater one for safety reasons. – Jonathan McDonald, Late Model Restoration
There are many issues with drum brakes, which is why they receive a bad reputation. Drums can be difficult to work on, the parts can sometimes be more expensive to replace than on a disc setup, and they’re not the best for bringing your Mustang to a halt. From a performance standpoint, they’re not ideal. Drum brakes will stop the car eventually. Drums rely on springs and hydraulic pressure to operate properly, whereas disc brakes work from a hydraulic standpoint by applying equal pressure to both rear brakes when the brake pedal is applied. The design of the drum’s linkage requires that the adjustments made must be precise to maintain the proper braking. If the linkage is not perfectly “centered,” it begins to lose its effectiveness. This translates to drum brakes requiring frequent adjustments that are critical to maintain adequate braking, and maximize the life of the shoe linings.
Drum brakes are also extremely notorious for losing braking power during spirited driving, which is one reason you’ll find they’re not ideal for performance applications – one of the biggest reasons why drum brakes receive a bad reputation. After a few hard applications, they begin to fade due to excessive heat buildup. This diminishes the effectiveness of the fluid and the shoes.
We spoke with Jonathan McDonald from Late Model Restoration. He commented that, “Upgrading from your factory drum brakes to a rear-disc conversion kit like this one is the most ideal situation for performance braking on the Fox body. The kit greatly increases the mechanical advantage by creating more leverage, which allows the car to brake more efficiently, and produces less heat. Keep in mind that when you swap to a rear-disc conversion kit, the rear of the vehicle is now able to perform braking duties a lot faster, thanks to the vented design of the rear discs, that generate only a fraction of the heat from the drums.”
The kit from Late Model Restoration includes everything necessary for converting your factory drum brakes into Cobra-spec rear discs. SVE incorporates the use of as many OEM-like parts in this kit as they can, so expect the new 28-spline rear axles to fit into the stock housing with no issues. With the new 5-lug axles and slotted 11.65-inch StopTech Performance rear-disc brakes, many new rear wheel options become available for the Fox as well.
The calipers are single piston and are black powder-coated to resist all types of corrosion. The kit utilizes StopTech Performance street pads paired with the discs, and the parking brake cables directly replace the factory ones with no modifications needed – another nice advantage of using SVE.
Installing The Kit
To begin, drain the rear-end to install the new axles. Set a drain pan under the differential housing, then remove nine out of the 10 bolts holding the rear differential cover to the axle housing. Loosen the tenth bolt, allowing the cover to become loose, and drain the old gear oil into the drain pan.
From left to right: While the rear end is draining, remove the rear wheels, then remove the drum. Once the rear end has drained completely, It's time to remove the axles. Start by removing the cross pin located inside the differential housing, then carefully push one axle outward at a time to gain access and remove each c-clip in the housing. Remove the axles from the housing.
Proceed by removing the entire factory drum brake assembly by removing the four nuts holding it to the factory axle flange. Once removed, install the new caliper mounting bracket provided. With the provided studs installed on the new axles, install the new axles, and secure them with the c-clips that were removed.
Reinstall the cross pin, being careful not to over-tighten it. When reinstalling the differential cover, we recommend the use of Room Temperature Vulcanization Silicone (RTV) to insure a proper seal. Once the differential cover has been put back on, fill the differential with the provided Royal Purple gear oil from the kit. Now is a good time to check if the axle seals and bearings need replacing.
From left to right: We took it upon ourselves to properly test-fit everything before beginning the installation. This is a good practice to know for anyone performing an installation. Next, install the bracket that holds the caliper using the provided bolts. Assemble the caliper, followed by the new pads.
After everything above is completed, we recommend removing the lower rear shock bolt, as it makes installing the brake hoses easier. Attach the new brake hose to the fitting on the caliper using the provided hardware, then reinstall the lower bolt.
Lines, Hoses, Valves, and More
One important thing to note is that this kit uses a ’93 Fox body Cobra brake master cylinder and Ford Racing proportioning valve – because of the additional stopping power needed for the new brakes. Late Model Restoration provides a Ford Racing adjustable proportioning valve, which allows for the rear brake bias to be set.
The provided three-port to two-port conversion kit from Ford Racing installs on the passenger side of the vehicle, in front of the firewall. Remove the plunger and spring, and install the new internals and the cap the kit provides.
With the factory union valve located on driver’s side inner of the fender, be aware that you will need to modify the stock proportioning valve (as explained above) to compensate for the new amount of fluid pressure from the new Cobra brake master cylinder. The new gutted valve allows you to make adjustments for the proper braking bias for the disc brakes, as the factory valve was designed for use on drum brakes.
The SVE rear disc conversion kit that Late Model Restoration provided for us includes a 1993 Cobra style brake master cylinder, which contributes a lot to the new pedal feel. Keep in mind, during the removal, the master cylinder will need to be bench bled. To finish the installation, install the new provided master cylinder, fill it with new brake fluid (now is the best time to check for leaks), then finish with bleeding the system.
We chose the ’94-’04 style because it means the enthusiast won’t have a hard time finding replacement parts in the future. Another advantage is that any aftermarket big brake kit from that era can be used as well. – Jonathan McDonald, Late Model Restoration
We couldn’t be happier with the new setup. The car stops faster and safer than before, and with more confidence now thanks to the new proportioning valve setup and the new Cobra master cylinder. During the initial testing of the factory configuration, we tested our Fox body three separate times and recorded the quickest stop. We managed a shortest distance of 169.86 feet, which took 4.81 seconds to achieve. With the new configuration from Late Model Restoration, we were able to record an astonishing difference in stopping distance. Our best distance we recorded was now at 148.66 feet, which only took 3.21 seconds to achieve. We saved an average of 21.20feet and 1.60 seconds, which are respectable gains over the factory components.
Our initial expectations for the kit were high, and we were very happy when Late Model Restoration met those expectations. When we asked McDonald what makes the kit perform so well, he replied with, “The kit features a vast majority of upgrades over the stock rear-drum setup from the factory. SVE uses ’94-’04 OEM Cobra-style brake rotors and calipers, which means any brake rotor or pad that era will fit this kit. We chose that platform because it means the enthusiast won’t have a hard time finding replacement parts in the future. Another advantage is that any aftermarket big brake kit from that era can be used as well.”
Our new rear-brake setup stops a lot more reliably and efficiently. We’re impressed with the performance this kit delivers, and we’re happy with the new appearance on our car. We couldn’t be any happier with the new brake setup on our Fox body.