The mods you make on a project car should be dictated by how you use the car. It sounds like a "no duh" statement, but you'd be surprised that most enthusiasts don't stop to think about this. For example, if you have a project car that is infrequently driven on the street, or is trailered to the drag strip, you most likely perform engine and horsepower related upgrades. On the other hand if you have a car that doubles as a daily driver, and you commute in city traffic, it'd be wise to put money into other systems which will yield usable results. For instance, perhaps you need better tunes, or the suspension is shot, or as in our case, the car needs better brakes. Modifications of these sorts aren't going to help you go any faster, but the point is that going faster and making more power isn't always what you and your car need. Spending some money in other areas can also yield noticeable results and performance of another variety which makes your ride that much better.

Brakes are one such area that we often settle for, especially on newer cars. After all it is a reasonable assumption that a new car has modern brakes and therefore there isn't much to gain by upgrading. In reality, just like anything else, there is always room for improvement. Mustang braking systems have evolved considerably over time. Beginning in 1999 Ford began putting some admirable brakes on some of the big guns in the Mustang lineup. The SVT Cobra, Bullitt and Mach 1 models all came with track worthy 13" front rotors and matching calipers. While all Mustangs from 1999-2004 are equipped with four wheel disc brakes, the 13" front brakes was still a sizable step-up from the GT's 11" rotor setup.

Back in the '60's if the factory made an alternative component standard on a specific model you had the option to purchase that upgrade on the base model. Those days are long gone. Since the late 70's the only way to get parts only sold on Ford premium makes and models is to purchase it over the parts counter, or through Ford Racing, afterwards. For that reason if you buy a 2004 Mustang GT and want Cobra brakes, well don't tell the dealer because he could care less and Ford simply doesn't play that way anymore. Fortunately while factory performance programs have

Top: Stock 11" GT brake rotor.
Bottom: 13" Cobra rotor and caliper fills out the wheel nicely.

withered away the aftermarket has flourished. Companies like Performance Parts Inc. make their business sourcing and selling OEM performance parts. In some cases they deal directly with Ford, in other cases they deal with the original suppliers. In either case the end result is a supply of original good stuff for us to upgrade our not-so-worthy base models.

Back to brakes. The '99-'04 Mustang GT came with 11" rotors up front. Nothing wrong with that for most people, but for guys who like to drive hard you won't sleep well at night knowing you could be at Cobra specs for just $400. Since paying a local shop for a good brake service with new rotors and pads can approach that cost, we figure you may as well do it yourself and put what you'd pay in labor towards a killer looking and performing set of brakes. We ordered up an entire kit from Performance Parts, which includes the 10th Anniversary red Cobra calipers and 13" Brembo rotors. We also spent a few bucks extra to get Goodrich D.O.T. approved stainless steel hose. The hose isn't necessary but will resist stretching or ballooning under extreme heat and pressure. Since we plan to autocross our car we figured this is cheap insurance.
Furthermore, and if anything, it comes down to aesthetics. Let's face it, who want's a killer looking car with great 17" or 18" wheels when what is behind them is a tea saucer? You don't see any of the Euro sports cars coming with anything but painted aluminum calipers and big pizza pie rotors. So, follow along and convince yourself how easy and worthwhile it is, then go out and do it.

Removing the Stock Brakes

Late model Mustang disc brakes are some of the easiest to work on of any auto maker. With the car on jack stands we go to work.
Since we are replacing the stock rubber brake lines we start by disconnecting them at the hardline junction. Use a 3/8" flare fitting wrench to avoid rounding the nut.

With the hardline disconnected use a screw driver to pry out the retaining clip which secures the soft line to the body bracket.
Prepare for brake fluid to seep out all over the place. We positioned the open end of the line higher than the caliper to avoid excess leakage until we had the caliper fully removed.

Use a 15mm socket to remove the two bolts which secure the caliper to the spindle.
With the bolts removed the caliper, pads and connected rubber hose can be removed as a unit.

Remove the pushnuts from the rotor studs. There is generally two pushnuts, save them for the new rotors.

Removing the factory rotors may require a good whack with a soft mallet.

The rotors can then be slid off the spindle hub. Note that on '99-'04 Mustangs the hub is sealed and the rotor is a "hat style" requiring no disassembly of hub or bearings.
Before re-assembly we thoroughly clean the rust and scale from the hub to ensure proper seating of the new rotor.


(Installing the Cobra Brakes)

In This Article:
Increasing the braking performance of your '99-'04 Mustang GT is an easy task when you borrow some parts from the Cobra.

  Performance Parts Inc.
We opted for an OEM Cobra/Bullitt/Mach1 rotor, produced by Brembo. The 13" rotor provides roughly a 30% increase in surface area over the stock GT 11" rotor. This means more "swept" area by the brake pads, resulting in faster stops.

Cobra Brakes
The twin-piston Cobra caliper is produced by Australian braking firm PBR. The GT caliper is also a twin-piston PBR caliper, however will not clear the 13" Cobra rotor. The Bullitt Mustang also used the same caliper as the Cobra, but the script is replaced with a pony.

  Goodrich Brake hose
To further improve performance, safety, and pedal feel we are upgrading to braided stainless steel brake lines. These are not an OEM part but are DOT legal and produced by Goodrich.


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