Fox Mustang Disc Brakes - Braking News

Are we being greedy or overly optimistic by trying to shoehorn a Shelby GT 500's massive front 14-inch rotors and four-piston calipers onto our Fox 500 project? Maybe both, but we did it just the same. Stay tuned-we'll keep you posted on how it all worked out.

Horse Sense: Instead of an engine's vacuum, a hydraboost brake system uses the power-steering pump to hydraulically minimize braking effort. These systems don't require a large vacuum reservoir, thus they take up a lot less space in the engine compartment.

As regular readers know, our latest build project is called the Fox 500, due to the fact that Editor Turner's personal '88 T-top hatchback is going to resemble some sort of SciFi Channel close encounter of a Fox platform and Shelby GT 500 running gear, once the talented and innovative crew at Paul's High Performance do all the hard work. So in keeping with this whole Fox 500 scheme, it makes sense to try and employ as much GT 500 supporting hardware as possible, right?

When new, Fox-body 5.0s suffered from infamously inadequate braking. With increased nose weight and roughly 500 ponies (to start with) coming onboard our blown 5.4-liter LX project, the guys at PHP accepted the challenge of trying to harness the enormous whoa-power of the Shelby's manhole-cover-size front brakes (available now through Ford Racing Performance Parts as PN M-2300-S). This idea wasn't without its tribulations, however, the most obvious being that no one at FoMoCo even remotely considered the idea of anything approaching 14-inch-diameter rotors when engineering the trusty old Fox. Think about it: These rotors are the same diameter as some wheels available on early Foxes.

Of course, our LX also needed some rear disc brakes for its shortened Strange 8.8-inch axle, along with a complete conversion to five-lug hubcaps, so we again turned to FRPP for its M-2300-K Cobra disc brake conversion kit. It encompassed everything we needed for braking out back and way more, including the essential SN-95 front spindles and an adjustable proportioning valve.

In order to squeeze the GT 500's broad-shouldered 5.4-liter into the Fox engine room, we also needed to switch to a compact hydraulic brake booster in place of the bulky factory vacuum booster, at least if there was to be any hope of retaining power brakes-something highly recommended in what we expect will become a regularly driven missile of a street car. Luckily, Hydratech Braking Systems had just what we needed: a bolt-in setup similar to that used on factory modular-motor SN-95 'Stangs.

So, before we run out of space, here's a quick look at the Fox 500's bodacious braking hardware. Now we just have to find rims-and maybe fenders-that will work with those gargantuan Shelby front binders.

We sourced our rear discs from FRPP's comprehensive M-2300-K kit, also snapping up its adjustable proportioning valve and, even more important, its SN-95-style spindles. Without these spindles, there would've been virtually no way to mount the Shelby brakes.

Even with the later-model spindles, the PHP crew had to make numerous revisions to accommodate the Shelby's massive Brembo calipers. Comparing the stock SN-95 example on the right to our modified spindle, you can see that considerable welding and redrilling had to be done to accept the wider mounting-bolt spacing of the GT 500 caliper. Don't try this at home, as the entire braking ability of the caliper-not to mention the retention of the whole rotating assembly on the car-is dependent on the strength of the spindle.

Additional welding/machining of the spindles was necessary in order to center the calipers over the rotors. There are many simpler ways than the Shelby GT 500 hardware to improve factory braking on a Fox-such as sticking with the FRPP M-2300K kit in its entirety. However, Editor Turner is stubborn. By the way, our modified rotors were treated to a black-oxide finish, and the formerly tapered tie-rod holes were enlarged to accept bumpsteer hardware.