Mustang Brake System Tech Guide

One must first understand the basics of the braking system to fully understand where improvements can be most beneficial. The braking components across Mustang generations have varied somewhat, the general basics and core components remain the same.

The brake cylinder assembly, located between the engine and the driver’s side fender, responds to pushing the brake pedal. Above the cylinder assembly is a brake fluid reservoir. The reservoir is usually semi-clear plastic, allowing you to easily monitor the level of fluid inside of it. As you push the pedal, you add pressure to the system. This pressure pushes the pistons in the Mustang's brake calipers, forcing the brake pads to contact the rotors and induce friction. The friction slows your Mustang down.

Brake line pressure can also be altered by the ABS (anti-lock braking systems). The computer utilizes wheel speed sensors located at each wheel. If it sees a difference in wheel speed while braking, the ABS module will trigger solenoids to relieve pressure from the faster spinning wheel. This is why you experience a pulsing sensation if you're hard on the brakes. This helps control your Mustang in extreme braking situations by sacrificing stopping distance.

When braking, your car’s weight is transferred to the front, requiring the front brakes to do most of the work. Larger caliper pistons and multiple pistons will provide more clamping pressure on the pad and rotor. This increases stopping distance and overall braking performance. This, of course, is only as good as the tires and suspension you have and their ability to transfer brake torque to the road effectively. Your upgraded brakes may be able to stop you in a shorter distance, but if your tires cannot handle the stopping power then it’s a moot effort.

• Brake Pads
• Rotors
• Calipers
• Brake Lines
• 5-lug Swap (Fox Body Mustangs only)

Brake rotors spin along with the wheels since they're both mounted to the hub via the wheel studs. The brake rotor is high grade steel and will often get a coating of rust very soon after a vehicle is washed or sits in the rain. You’ll see this often with cars at a dealership waiting to be sold. This is nothing to worry about. The brake pads will clean the rust coating off the first time they stop the car.

Surrounding part of the rotor is the brake caliper. On Mustangs, brake pads sit on a pad holder, so you can remove the caliper without removing the brake pads. A piston on the backside of the caliper applies the pressure that squeezes the contact surface of the pads against the brake rotor, bringing your Mustang to a stop.

Drum Brakes: The Mustang hasn’t seen a rear drum brake for many years. However, on older Mustangs such as the Foxbodies, a front disk and rear drum brake setup was common. Instead of utilizing a disk, the drum brake uses a slightly different configuration with the pads positioned inside a steel drum. Disk brakes offer more stopping power, and a rear disk brake conversion is often at the top of the list for those with rear drum brakes. On top of that there are more mechanical parts involved with drum brakes, so routine maintenance is more complicated due to the various springs and clips needed.

Anti-Lock Components: With the introduction of anti-lock brakes, a few additional components were installed at each wheel. These are a toothed speed sensor ring and a speed sensor. The sensor sees the teeth passing by it, knowing that this means the wheel is rotating. When the brakes are applied and the sensor sees that the teeth are no longer moving by the sensor, it knows that particular wheel has locked up. The anti-lock control unit will then pulse the braking power to that particular wheel.

As a side note, the anti-lock braking system is also used by the traction control system. If the sensors indicate the wheels are spinning too fast for the car’s actual speed at the time, power from the engine is restricted until wheelspin is corrected.

Brake Pads: The factory brake pads can often be noisy, as they have a tendency to squeal when applied after they have several thousand miles on it. They also produce a lot of brake dust especially on the front of the car since the front brakes work harder than the rear. While braking performance from the stock pads is much improved in the newer models than in older Mustangs (Fox-Body owners know exactly what I mean), those who push their cars harder will undoubtedly look for more braking power and less braking fade when repeated high speed stops are made.

Factory pads are designed to be softer on purpose. Reason being, believe it or not, the softer pads provide more stopping power sooner than aftermarket pads. The idea is to provide as much stopping power as soon as possible when the brakes are applied suddenly (a situation a daily driven 'Stang might run into). The reason the brakes get upgraded is because of heat. Factory pads are more susceptible to brake fad; they can't take demanding stops repeatedly without essentially melting.

There are several aftermarket pad options to address these concerns. Carbon-based pads such as the HPS pads offered by Hawk are an example of this. They can take more heat AND provide better emergency braking. They still produce more dust than their ceramic cousins, but this is a good all-rounder option.

If you’re looking for the ultimate in stopping power and a near complete elimination of brake dust, then ceramic-based pads are your go to. Ceramic pads provide quiet, powerful, and near dust-free operation that is superior to even the best carbon-based pads. When compared to stock replacement pads, high performance pads are a little more costly, but well worth it if you’re looking for improved operation.

Race pads are designed to actually perform better after they warm up (yes, race brakes don't stop the best when cold). After repeated stops, race pads actually bite harder than they would if you've been cruising on the highway for several miles. Needless to say, this isn't so handy on the street where you need 100% of your braking randomly and usually suddenly. Something else you'll want to consider is peak force. The peak force is the maximum decelerating effect that can be obtained. The peak force is often greater than the traction limit of the tires, in which case the brake can cause a wheel skid. In other words, don't get too much braking than your tires can handle.

There are 3 questions to ask yourself when buying new pads. How hard do you drive/brake? What type of driving do you do? What is this pad going to be used for?

• HPS = Semi all-rounder. Good on the drag strip (one big stopping event) and the street.
• Ceramic = Consider these as upgraded daily driver pads.
• HP Plus = Track/Autocross only. Not suitable for daily street use

Improved pads and rotors will help you enhance your car’s braking ability, but it will only take you so far. If you’re aspiring to move to the next level, conversion kits are the way to achieve this. Think of a conversion kit as a supercharger for your brakes, giving you a substantial increase of 50% or more stopping power. Consider it this way. With a conversion kit you get a bigger surface area so friction can do its job even better. That bigger surface area also allows the brakes to dissipate heat faster so you don't experience brake fade after a stop or two. Conversion kits vary widely in price, depending upon the route you wish to follow. Ford offers the upgrades found on its special edition Cobra and Mach I Mustangs, while renowned companies such as Brembo offer high end conversion kits that offer the ultimate in stopping power.

Should I upgrade my Mustang to a big brake kit? For high performance Mustangs, people tend to work on maximizing the amount of power that their motor creates, but they never consider when you drive faster you will need to stop faster. Upgrading to a “big brake kit” will increase the surface area of your brake pads and rotors, allowing the system to work faster and more efficiently.

• Larger rotors
• Tougher pads
• Bulkier calipers
• Hardier brake lines

Some kits are designed for the front only or the rear only, but there are some that feature everything for the front and back of the car. These kits are a one-stop-shop for your braking needs, giving you everything you need to make a drastic difference in your braking performance. If you want no-holds-barred braking, then a big brake kit is your logical upgrade.

The aftermarket rotors are often offered in two variations: slotted and cross-drilled. Both are a vast improvement over stock. Basically there are holes, or slots cut into the surface of the rotor. This allows heat to escape the surface of the rotor when the brake is applied. The brake calipers on the aftermarket kits are usually a three or four piston design. The benefit of this design is a more even, and stronger clamping force.

As far as wrenching on your Mustang goes, brakes are one of the easiest systems to work on. The brakes are relatively easy to get to and you only need a small selection of tools to get the job done. It can be a daunting job to think about, but as long as you follow the instructions for the install or watch a video tutorial, you should be good to go. 

If you have no interest or confidence in taking on the job yourself, almost any automotive shop will be able to take on the job for sub $400, but this may vary. It is best to get multiple estimates before getting any work done to your Mustang to ensure you are getting the best price.

One major component of the Mustang’s braking system is the master cylinder. It should be inspected periodically and replaced if defective. It is one of the most important parts on the car. It basically provides the hydraulic force to engage the brakes. As with all hydraulic devices, there are seals used that eventually leak. Be sure upon inspection the seals are okay and the brake fluid is at the proper level.

Another important thing to check is the brake fluid. It should be a clear, golden color. The brake fluid is designed to trap moisture and particulates in the brake system; therefore, it should be replaced every two to three years minimum. Many aftermarket brake systems will include a quality brake line that attaches to the caliper. If not, inspect your factory line and be sure there are no leaks or visible damage to the line. It’s a good idea to flush the brake fluid from the entire brake system when performing this install. Have a local shop do it if you’re not comfortable with the procedure as it will require the ABS pump to be cycled a few times to rid itself of any old fluid.

Another popular upgrade option is aftermarket brake lines. The factory brake lines are often rubber-based, which tends to flex under heavy use. Aftermarket lines that utilize stainless steel with materials such as Teflon do not flex and expand under the extreme pressures the lines see when the brakes are applied heavily. The result is better braking response, and a much firmer feel at the pedal.

Unless equipped with special brake systems (IE, Brembo), Mustangs primarily come with 3/8 fitting sizes. These can be changed with aftermarket equipment. Few models will have an AN style fitting, mostly -24, but that is not as common.

Rotors make the contact with the brake pads in order to slow the vehicle down. Without the rotors, the brake pads would simply touch each other and a Mustang would not see any decrease in speed other than friction from the road and other outside factors. Rotors are designed to be smooth and spin with the rotation of the wheel. As a result, in order to slow the wheel rotation, you apply the brakes which slow the rotor rotation.

• Upgraded brake rotors increase stopping distance and overall braking performance
• Brake rotors are essentially the radiators of your brake system, keeping your pads hot enough to slow you down, but cool enough to control wear
• In addition to improved braking performance, aftermarket brake rotors can improve cooling and increase resistance to cracking from thermal stress

Brake rotors can be replaced as part of a conversion kit, or on their own. Heat is a byproduct of the friction between the rotor and the brake pads. To enhance braking power, you’ll want to combat the heat. Aftermarket rotor manufacturers do this in a variety of ways. First, they may use a different grade of metal for the rotor. Techniques such as cross-drilling or slots, sometimes a combination of both, also help provide more surface area and better airflow to aid in cooling. Both styles work well, but many times cross-drilled rotors tend to crack under extreme braking conditions.

One thing to keep in mind with aftermarket rotors is maintenance. Some shops will not machine slotted or cross-drilled rotors, which may make maintenance a little more trouble than it would be with stock components. So plan ahead, and make sure you have plans for when that day arrives.

There are primarily four types of rotors. The proper one for the application can depend highly on the intended purpose. A list of different rotors and descriptions are listed below. 

• Smooth: The smooth rotor presents the most surface area while also allowing for constant contact. Under most driving conditions, these are perfectly acceptable methods of driving. As a result, most factories place these on cars they produce. However, for the ones who want higher performance, there can be other options.
• Slotted: These types of rotors have small grooves placed into the rotor (so it is not 100% smooth). The theory is as brakes are applied, heat is generated. The slotted portions allow for the gases from the heat to escape and keep temperatures cooler. These are excellent for road racing, but retains the potential to accelerate brake wear. 
• Cross Drilled: Cross drilled rotors are the rotors with the holes all throughout the rotor. To some, these are the "cool" rotors. They use the holes to allow the gases to escape and keep temperatures cooler. They also can allow for water to escape with ease if driving in wet conditions.
• Drilled and Slotted: This type of rotor places a combination of the drilled and slotted together. These are especially beneficial to heavy vehicles towing heavy loads. 

While all the rotors have their place and application, they are not all qualified for the same job. Smooth rotors, while perfect for the majority of the time, have their performance limitations in regards to heat generation for road racing. After a few laps, brake fade will begin to set in and no longer perform well. 

Slotted rotors are preferred for road racing, however, they can create grooves along the edges of the slots. These grooves can become sharp and tear through brake pads, greatly accelerating wear. Cross drilled rotors, while beneficial in the past, have been almost replaced by slotted rotors. 

The reason for this is that cross drilled rotors tend to have problems with cracking due to the stress under extreme use. In a similar fashion, drilled and slotted rotors have the same susceptibility to crack under extreme stress. 

Slots in rotor faces are partly a carryover from the days of asbestos pads. Asbestos pads were prone to surface glazing and the slots tended to help scrape and de-glaze them. Similarly, cross drilling the rotor helped by providing a way to expel the gasses created when certain bonding agents employed to manufacture the brake pads began to break down at very high temperatures. This condition was referred to as out-gassing. When it did occur, the driver could still feel a firm brake pedal, but a large reduction in pad friction. This normally only happened at temperatures experienced in racing. However, with modern race pad technology, out-gassing is no longer an issue with pads designed for racing. With that said, slotted rotors are still advantageous to dissipating heat and is a must-have for anyone who plans on navigating road courses.

At the end of the day when it comes to buying aftermarket rotors that are cross drilled, slotted or both for your Mustang, just know it is for aesthetic value, as well as heat and a slight weight reduction. If your Mustang is going to see a race track then slotted is the preferred choice. With certain pad compounds slotting can help wipe away debris from between the pad and rotor in turn increasing the quality of friction between the rotor and the pad.

For street and occasional light duty track use, they will hold up fine. One good benefit when it comes to street driving is both cross drilled and slotted rotors break up the water film formed when driving in wet conditions. This effect is most evident with cross drilled rotors, due to water flowing through the holes. It should also be noted, most aftermarket brake rotors are zinc plated. This improves corrosion resistance and also gives the rotor a nicer look because of its oxidation resistance.

Another option you will see is dimpled rotors. This has the same effect as cross drilling but not the weakness of drilling. Like other aftermarket Mustang rotors, dimpled rotors offer better cooling and out-gassing than stock. Since the dimples are small indentations in the face of the rotor and not holes that go all the way through, they offer better structural integrity than drilled rotors.

The ideal rotor to get can vary depending on the application. While a smooth rotor is perfect for a daily driver, they are not the best choices for road racing. Drilled (drilled and slotted) rotors look very beneficial in terms of aesthetics, but they are not the best for road racing either. 

Slotted rotors, while ideal for road racing as well as daily driver use, leaves the brake pads open to quicker replacement. The perfect rotor for you can be narrowed down by thinking about the most common type of driving and weather conditions you as a Mustang owner will see. 

The 11.5 inch front rotors typically require a 17 inch or larger wheel. However, if you upgrade to 14 inch rotors you'll need at minimum an 18 inch wheel.

When you buy a new set of rotors you will want to bed or burnish them in. You do this by making 8-10 60 MPH to 5 MPH stops. You will start to smell your brakes wearing in--this is a good thing. This process puts a layer of brake pad material on the rotor. Now your friction power is maximized and you can enjoy your new rotors throughout regular driving and the more extreme conditions seen when auto crossing.

Cooling Kits: You’ll also find various brake cooling kits on the market that use air to cool the brakes. Generally this is performed for the front brakes as they tend to do most of the work. The kits usually use openings that were designed for fog lights, or maybe even part of the openings that direct air to the radiator. Then ductwork channels the air towards the brake rotor and brake pads.

Line Lock/Brake Control​: The drag racing crowd will often use a unique brake accessory to help facilitate heating up the tires during a burnout. Often referred to as a “line lock”, the brake control is used to lock the brakes on the front wheels in place to hold the car still during a burnout. To do this a solenoid is activated by a switch after the brake pedal is pressed. The solenoid holds hydraulic pressure on the front brake lines, in the same manner if you had kept the brake pedal pushed down. The difference is that the rear brakes are not activated. This saves wear and tear on the rear brake components when compared to trying to use the entire braking system to hold the car still for a burnout. It also allows the rear tires to turnover easier and to develop more heat for starting line traction.

The e-brake generally works similarly to the way the foot brake does. However, the big difference is the e-brake uses a ratcheting system. Therefore, when the brake is set, it will stay in place and does not require constant pressure to apply the brake pad to the rotor. Also, the e-brake is entirely mechanical. There is no hydraulic system (it's separate from the traditional foot brake system). This is to counter the potential of a broken line where all hydraulic fluid is leaked or cannot be compressed.

If you’re looking for a way to enhance the appearance of your Mustang, but you don’t want to shell out the cash for new brake equipment, caliper paint or caliper covers may be what you’re looking for. The Dupli-Color kits are a good example of caliper paint, although there are many different options available. Some manufacturers even offer caliper paint that is an exact match to the exterior paint of your car.

Another alternative is caliper covers. Caliper covers are made to fit over your existing calipers, giving them the appearance of an aftermarket caliper. They also help reduce the amount of brake dust that reaches the wheel. Installation only takes a few minutes, and therefore even easier and less time consuming than painting your existing calipers.

So what should you go with? For the best results, we recommend the caliper covers. The caliper painting process can be messy and inconsistent. There is also a lot prep work involved. The caliper covers eliminate the mess with an easy bolt-on installation. 

As you can see, there’s a lot more to the braking system than simply a set of pads and rotors. Next time you have a little cash burning a hole in your pocket, remember your car’s braking system. There are several upgrade options that can easily set your car out from the rest of the Mustangs on the road!

Upgrading brake systems can create issues with clearances for wheel fitment. Simply changing rotors and pads will not affect clearance, however changing the brake caliper itself can cause issues. While at first glance it is easy to assume it is in direct relation to the wheel diameter, this is not always true.

The barrel of the wheel itself (how far it goes into the center, from the outer rim towards the center basically) has a large impact on clearances. While a 20" Saleen wheel will not fit certain calipers, an 18" AMR wheel will accommodate all of the calipers. Each wheel is subject to its own fitment clearances and restrictions.

As for stock wheels, it can vary. If a mustang came stock with a performance pack or track pack, there should not be any clearance issues changing calipers (unless a much larger caliper is being utilized). If it came equipped with the basic level wheels, most likely different wheels will need to be obtained in order to use larger calipers.

The first step is printing a template usually found from the manufacturer’s website (usually as a PDF file). You’ll need to save it to your computer in case you need to print multiple copies. After you open the file, you’ll see a cross section illustration of the caliper and a measuring scale. When printing the template, you must confirm the scale is correct with a ruler or tape measure. Only after you have verified the template has been printed to the correct size can you glue the entire page to a piece of stiff cardboard.

With a pair of scissors, cut around the BOLD dotted lines, but be sure to leave the “hub” section of the template intact until you have accurately measured the inside diameter of your wheel’s hub. After determining the correct inner diameter of the hub hole, trim the final size of the hub area on the template using the preprinted measured lines.

With your brake caliper template ready, place it into the backside of the wheel you want to check. The hub area of the template should fit down into the hub opening of the wheel. Now you can check for clearance around the barrel and the spokes. Most manufacturers recommend at least a 0.100" (2.54mm) clearance to any point in the wheel.

Bad Fit: the caliper portion of the template will extend too far past the spokes of the wheel, which would not allow you to run the wheel with the particular big brake kit.

Good Fit: the caliper portion of the template sits well above the spokes of the wheel with plenty of clearance in all directions. The wheel could safely be used with the brake kit with no clearance issues or rubbing.

Be sure to pre-test fit the kit with the wheels you’re looking to run with the help of the manufacturer’s brake caliper template. By pre-test fitting the brake kit before making your purchase, you will save yourself from the possibility of any clearance issues or major headaches.

• Make sure you have access to a good printer for the template and double-check the scale
• Measure once, cut twice
• Check the hub diameter and trim the template appropriately
• Match up the template to your Mustang and to determine a bad or a good fit
• Other upgrades exist outside of big brake kits

If you’re not quite ready to upgrade to a big brake kit just yet, you can still improve the braking performance of your Mustang by installing a new set of brake pads, rotors, and hoses.

When you hit the brakes on your Mustang, the pistons in the caliper push on the brake pads, which causes the brake pads to clamp the rotors. The force of the pads on the rotors creates a lot of friction, and with friction comes heat.

As the pads get hotter and hotter, they lose their ability to keep friction on the rotors, which is called brake fade. To prevent brake fade, you need to increase the thermal capacity of the braking system or increase airflow over the brakes to cool them down.

The best way to increase the thermal capacity of the brake system is to install larger rotors on your Mustang. The larger the rotors, the more material there is available to absorb and dissipate the heat generated during braking. You can not just install larger rotors on your Mustang, because they will interfere with your calipers.

You need to install one of many aftermarket big brake kits such as Brembo or Wilwood. These kits include larger rotors and more powerful calipers. An inexpensive way to upgrade your brakes if you have a V6 to install GT brakes, or if you have a GT you can install Cobra or GT500 brakes.

You will also want to replace your brake fluid as well, since the stock fluid is not really equipped to deal with large amounts of heat, and has a relatively low boiling point compared to performance brake fluid.

The best type of brake fluid is what the manufacturer recommends. While DOT 3 and DOT 4 fluid can commonly be interchanged, they can not be replaced with DOT 5. The main difference is the boiling points of the fluid. DOT 3 has a wet boiling point and dry boiling point of 284 and 401 degrees Fahrenheit while DOT 4 and 5 are 311/446 and 356/500.

Most Mustangs take about 2 liters of fluid to flush the whole system. However, that can vary based on the condition of your Mustang's brake system. For safety's sake, 2-3 liters is a good bet for a full and proper flush.

Swapping your factory brake pads is a fast and inexpensive way to reduce brake fade. Factory brake pads are designed for longevity, quiet operation, and low dust. While this is good for daily driving, the compound used will overheat higher operating temperature than OEM. The increased braking performance comes at a cost though, the different pad compounds offered are generally more noisy than stock pads until they are warmed up. They also require more heat to work properly, so the first few stops in the morning might squeak and may not bite as hard until the pads are warm.

The final step to controlling your brake fade is to increase the amount of airflow over your brakes to help cool them down faster. You can do this by installing drilled rotors. Installing rotors full of holes may seem counterintuitive since we discussed adding more rotor material to increase thermal capacity, but drilled rotors have more areas for heat to escape.

They allow more air to flow through and around the rotor, allowing it to dissipate quicker. Brake cooling ducts are another popular upgrade for the brake system. These are generally installed on the front of the car with scoops drawing air from the front lower grille.

This air is channeled through tubes that are connected to the back of the dust shield. This extra air will rapidly cool the brakes down, especially when used in conjunction with drilled rotors.

To recap:

• Brake fade is caused by being unable to dissipate heat during/after braking
• Brake fluid is rated by the fluid’s boiling point. If you frequently overheat your brakes, better fluid is a good idea for a simple upgrade
• Larger rotors provide more surface area to absorb and dissipate heat
• Larger rotors will require different calipers, so it’s more cost effective to get an entire big brake kit
• Harder brake compounds can take more heat, but also need a few stops to warm them up. Not always the best choice for a daily driven Mustang
• Drilled and slotted rotors shed heat faster than standard rotors, but eat up brake pads faster

For a Mustang that is daily driven, raced occasionally at the drag strip, or is used for autocross, a good set of pads, drilled rotors and upgraded brake fluid is about all you will need. These upgrades will make for a Mustang that can handle increased braking temperatures with relative ease.

If you plan on road coursing your Mustang, it would be wise to invest in drilled rotors, upgraded pads and fluid, cooling ducts, and a big brake kit. With the full treatment you will be able to keep your Mustangs brakes running cool and fade free for many years to come!

This process should be done when you replace your Mustang's brake pads. This will help prevent excessive noise and vibration. Bedding new pads also remove impurities from the friction surface and lays down a thing layer of pad residue on the rotors. Brake bedding is done by heating and cooling the brakes after repeated "braking events".

How long it can take for new brakes to be fully bedded:

• New brakes pads & new rotors= 800-1000 miles
• New brakes pads & worn rotors =200-300 miles 
• New brakes pads& badly worn rotors= can take up to 2,000 miles

Procedure steps:

• Find an open stretch of road that will allow you to get up to appropriate speeds (45 mph) and have the distance to decelerate (you'll need to do this a few times)
• Accelerate to 35 mph and apply moderate brake pressure to reduce your speed to 5-10 MPH. Do this 3-4 times
• Now increases your speed to 45 mph and brake to 10 mph. Do this 3-4 times as well
• DO NOT come to a complete stop. You can risk melting the pads completely, causing a glazing effect. This hinders your brake pads' effectiveness
• Once you're done your 45 mph runs, park the car and allow the brakes to cool for an hour. Try to avoid using the brakes when parking as well as avoid engaging the e-brake

Emergency brakes in Mustangs can be a bit of a mystery to some. This is because they use old technology. The primary braking system is a disc brake but inside, we find an older style drum brake set up for the emergency brake system. If you’re used to servicing drum brakes, the spring and lever system within can be a bit intimidating, but older Mustang owners will tell you there’s nothing to be afraid of.

Drum brakes are a bit of a pain, especially when it comes to wrestling springs and clips, but they are a very simple design and easy to service. To replace e-brake shoes, the discs will need to be removed. From there, you will need to remove the retaining springs and clips. During servicing, you may want to consider replacing these parts too. Then, it’s as simple as putting the new shoes in place and securing them with the appropriate springs and clips. Be sure to take pictures as you work for reference, even if it isn’t your first time.