Comparing Popular SN95 Brake Kits, Brake Fluid, and Installation

[b.mad@MaddRetros]

I wrote an article about the brake kits, however, i ended up splitting it into 4. I will be updating this list on the website, so to get a more "up-to-date" list, please click the specs link below.

What to look for: https://maddmotorsportsdesign.blog/2017/11/05/your-guide-to-find-whats-important-for-you-and-your-brakes/

Brake Fluid: http://maddmotorsportsdesign.blog/2017/11/11/guide-to-the-top-brake-fluid-by-boiling-points/

Specs: https://maddmotorsportsdesign.blog/2017/10/30/brakes-what/

Install: https://maddmotorsportsdesign.blog/2017/11/12/installing-the-sn95-wilwood-brake-kit/

Edited November 23, 2017 by b.mad

[b.mad@MaddRetros]

When it comes to brakes, everyone thinks that bigger is better. However, they do not take into consideration the weight and the caliper itself. What setup will be superior, one with a 14" rotor and 6-piston caliper, or one with a 13" rotor and 4-piston caliper? You would think 14" rotor and a 6-piston caliper, however, that is NOT always the case. What are things to consider when purchasing a brake kit?

1. First and foremost, is the brake kit a direct bolt on, or do you need to custom-make something like a bracket. The moment you have to custom-make something, the price goes up. Most companies offer direct bolt on kits.
2. Why are you upgrading your brakes? Whether it be for show or for track, knowing the reason for upgrading your brakes is a good thing.

If you are upgrading your brakes, here are a few things to look for:

1. Type of caliper: You can have a monobloc caliper, or you can have a multi-piece caliper. Also, you can have a fixed caliper, or a floating caliper.
2. Type of material for caliper: The material matters because of the metal properties. Some materials "flex" more than others.
3. Finish: Yes, the finish makes a difference.
4. Number of pistons: This is important when looking at pad wear.
5. Piston area: This matters more than the number of pistons.
6. Rotor size: The rotor size affects the overall brake torque.
7. Rotor vane design: Straight vs curved vs solid
8. Weight: When looking at rotor weight, you have to keep in mind rotational mass. 2-piece rotors tend to be lighter than 1-piece rotors.
9. Cost and availability: You can have the baddest kit out there, but if you break something out on the track, you cannot run to the parts store and buy a replacement. You will need to special order the part, and pay more money than a standard part.
10. Brake bias: This is crucial when trying to balance braking.
11. Tires: Brakes do not stop a car, tires do.
12. Brake pads: Make sure you pick the right one for your application.
13. Brake fluid: picking one with a higher boiling point is important.
14. Brake lines: Stainless Steel braided, or rubber.

• The type of caliper and the material of the caliper both play a part in the structural design of the caliper, which translates to flex. For this, we go to Wilwood Engineering's FAQ about caliper flex.
  • Q: Which is the more ridged Caliper, a two-piece or a monobloc?
  • A: Everything being equal, a properly designed two-piece caliper will flex less than a monobloc caliper. Stiffness is a function of the material’s modulus of elasticity. Steel bolts have an elastic modulus approximately three times that of aluminum bridges. There are some exotic aluminum alloys that were developed for F-1 racing that have almost the same elastic modulus as steel; however, they are expensive and not normally seen in after market brake kits. Steel has the added benefit of not losing its elastic modulus as things heat up. As a matter of fact, steel’s elastic modulus actually increases in stiffness as temperatures rise above 200 degrees F by approximately 30 percent, where it stabilizes at 400 degrees F. Aluminum on the other hand, loses approximately 50 percent of its stiffness by 300 degrees F.
  • Q: What is the difference between fixed and floating Calipers?
  • A: The primary difference between a fixed or floating caliper is in the mounting design. Fixed calipers are solidly mounted to the spindle or bracket, and floating calipers float on a pin that is attached to the spindle. Fixed calipers have opposing inner and outer pistons. Floating calipers have only inner pistons and rely on outer pad carrier movement to apply pressure to the outer pad. Floating calipers tend to be more forgiving to OE manufacturing tolerances hence they are used on the vast majority of production cars. On the other hand, fixed mount calipers that transfer PSI within the caliper into braking performance with a much higher efficiency are typically used on high-performance cars and for vehicles exclusively employed in racing for that purpose.
  • The finish of the caliper makes a difference when it comes to corrosion, wear, and heat transfer. Having a caliper with a finishing will protect it against rust and the elements. However, if you are racing, you are worried about heat. Nickel plated calipers also transfers heat out of the caliper body better than powder coat.
• The number of pistons and piston area are important because that tells you the force that is being applied.
• What is piston area, and how is it calculate?
  • As per Wilwood, the pistons area is the total surface area of all the pistons in one half of the caliper. The piston area can be determined using the formula: Area = pi x the piston radius squared x the number of pistons. For an example, lets use a six piston caliper and for ease of math, let's say that all the pistons are equal in diameter at 1.5 inches: 3.14 x .5625 x 3 = 5.29 square inches.
• Why is piston area more important than number of pistons?
  • "Larger caliper pistons will provide more clamping pressure on a given axle, and therefore increase the braking performance of that axle, providing the tires and suspension are able to transfer that brake torque to the road effectively. If the caliper pistons are too large for the application, they’re likely to cause excessive pedal travel and an adverse change in front to rear balance resulting in longer stopping distances. It is also possible that clamping forces can become so strong that pre-mature lock-up will occur, making brake modulation difficult."
• When racing, you want to avoid running drilled rotors. It is a common recommendation because it is said that drilled rotors crack easier than slotted rotors or solid rotors.
• When discussing how a larger diameter rotor helps braking boils down to one thing, leverage. Same applies to using a breaker bar to break loose a stubborn bolt. More force is applied to stop the car. However, a larger rotor comes with a higher cost, larger wheels, and added weight (rotational mass). So when deciding to upgrade, you have to make a list of pros and cons. Are the extra X pounds and $X worth the extra X of brake torque?
• When looking at rotational mass, a thing to consider is rotor weight. Generally, 2-piece rotors are lighter due to their design, and the use of an aluminum hat. Another advantage of a 2-piece rotor is the fact that it allows the ring to expand with heat, without affecting the hat, and since the hat is aluminum, that material dissipates heat better.
• The design of the rotor itself is crucial to its ventilation.
• Solid rotors are fine for light use, or use in the rear brakes for the street. The heat SHOULD not be high enough to cause issues. However, when you are harder on your brakes, you might want to look at a vented rotor. Not only does venting make a rotor lighter, but it helps with the cooling of the rotor.
• Straight vane rotors are very basic and provide minimal cooling compared to curve vane rotors. Curve vane rotors improve the cooling by channeling cool air from the center of wheel and act as a heat exchanger.
• When talking brake systems, something to think about is the cost of the system. It is important because not everyone has the same budget. Also, if you are at a race, and you warp your fancy 2-piece rotor, you cannot be to the local auto parts store and order a new one. You will need to order one online, and pay more money than the OE replacements at the local parts store.
• Why is brake bias important? Because brake bias slows you down. Bigger is not always better when your bias is off. When you slow down, majority of the weight gets thrown forward (weight transfer). Would it make sense to have a better kit in the rear than in the front? No, because the majority of the weight is in the front. A good thing to note is the locking of brakes. If your rear brakes lock up before your front, you have too much rear bias. If your front brakes lock up before your rears, you have too much. The key is to NOT lock up your brakes, because you do not stop. A lot of cars are equipped with ABS systems, which uses sensors on each wheel to determine if a wheel is locking up. It sends a signal to the module, which will regulate pressure to that wheel. However, ABS does not fix brake bias, it just masks it. You will need to spec out your system so that the front and rear systems work together and decrease your stopping distance.
• Why do tires play a role in stopping? Because friction. The more sticky the tires are, the more friction there is with the road. When upgrading your brakes, you must consider upgrading the tires too.
• When picking brake pads, you have to understand that a good brake pad is going to be noisy and messy. You will need to figure out if you want a race compound, or a street compound. There is no such thing as dual purpose pads. You can get a street compound with a higher temp range and use it for the track, however, it is still a street compound. And the higher the temp range, the more they will squeak when using them in the street.
• Rubber brake lines tend to flex and expand with heat. Stainless steel braided lines can handle more pressure, and would not expand with heat, just translates to better line pressure and better pedal feel.

[b.mad@MaddRetros]

When choosing a brake fluid, you have to consider its boiling points. There are two, wet and dry. What is the difference? Dry is brand new, fresh, not contaminated fluid. Wet boiling point will be with 3.7% water by volume. Keep in mind that as soon as brake fluid touches oxygen, it will begun to absorb moisture. Sure, fluid with a high dry boiling is nice, but wet boiling point is just as important. If you boil your fluid, you will not stop. Here are the top 10 fluids in both boiling points:

Dry Boiling Point:

AP Racing Radi-CAL R4 644*F
Pagid RBF 626 626*F
Wilwood EXP600 PLUS 626*F
Motul RBF 660 617*F
Carbon Lorraine Racing 617*F
PFC RH665 617*F
AP Racing Radi-CAL R3 608*F
Castrol REACT SRF Racing 608*F
Motul RBF 600 593*F
AP Racing Radi-CAL R2 593*F

Wet Boiling point:

Castrol REACT SRF Racing 518*F
Motul RBF 600 420*F
Wilwood EXP600 PLUS 417*F
AP Racing Radi-CAL R4 399*F
Motul RBF 660 399*F
AP Racing Radi-CAL R3 399*F
AP Racing Radi-CAL R2 399*F
ATE Type 200 395*F
Pagid RBF 626 392*F
Carbon Lorraine Racing 383*F

 

[b.mad@MaddRetros]

Ever wonder what to look for when it comes to brakes? Please take a look at the info article about brakes here. After you figure out whats important, the next step is knowing what is out there. And after you decide on your brakes, you can decide what to look for in fluid. I have some information on the fluid here. I did a lot of research when picking my brakes, and going to share that info below. The information below relates to the SN95 Mustang and the most popular brake setups.

Specs will be as follows: Caliper name (piston number), weight w/bracket (LBS), piston size (inches, 4-piston calipers will have 2, and 6-pistons will have 3), and piston area (in^2). Rotor specs are as follows: Rotor Material/style, rotor size (inches), rotor/hat Weight (LBS). All information was given to me by the respective manufacturer and/or their dealers. In some cases, the information was measured by myself, and other information was taken from online sources. FYI, floating calipers (which are the GT and Cobra (front and rear) calipers), the area is doubled. So keep that in mind.

• Wilwood Engineering:
  • Front FSL4: 5 lbs, 1.88"/1.62". Total area: 4.84
    • Spec-37 Iron/GT Slotted/Plain: 12.88"x1.25", 13.7 lbs
    • Spec-37 Iron/GT Slotted/Plain: 12.19"x1.25"
  •  Front FNSL6: 5.5 lbs, 1.62"/1.12"/1.12". Total area: 4.04
    • Spec-37 Iron/SRP-BLK Drilled/Slotted: 14"x1.25", 19.6 lbs
    • Spec-37 Iron/SRP-BLK Drilled/Slotted: 12.88"x1.25", 13.5 lbs
  • Rear Combination Parking brake (1): 6.1 lbs 1.62". Total Area: 2.06
    • Spec-37 Iron/SRP-BLK Drilled/Slotted: 12.88"x1", 12.3 lbs
• Baer Brakes:
  • Front Pro+: 5.5 lbs, 1.625"/1.375"/1.1875". Total area: 4.66
    • Rotor: 14"x1.15", 22lbs
    • Rotor: 13"
  • Front Track4:
    • Rotor: 13"
  • Front Extreme+
    • Rotor: 14"
  • Rear SS+: 3.5 lbs, 1.375"/1.375". Total area: 2.97
    • Rotor: 13"x0.810", 13 lbs
  • Rear Pro+: 5.5 lbs, 1.625"/1.375"/1.1875". Total area: 4.66
    • Rotor: 14"
    • Rotor: 13"
  • Rear Extreme+
    • Rotor: 14"
  • Rear 1994-2004 Cobra/Bullitt/Mach 1 EradiSpeed+ Rotor Upgrade
    • 11.63"
  • Front 1994-2004 Cobra EradiSpeed+ 2-Piece Rotor Upgrade
    • 13"
  • Rear 1994-2004 GT/V6 EradiSpeed1 Rotor Upgrade
    • 13"x0.5", 15 lbs
• Stoptech Brakwa:
  • Front ST40: 8.4 lbs, 1.33"/1.57". Total area: 3.32
    • Rotor: 14"x1.25", 18.1 lbs
    • Rotor: 13"x1.25", 17.2 lbs
• OEM Brembo Brakes:
  • Cobra R:
    • Front Caliper: Weight N/A, 1.41"/1.57". Total area: 3.5
      • Rotor: 13"x1.1", 19.1 lbs
    • Rear Caliper: Weight N/A, 1.49". Total area: 1.74
      • Rotor: 11.65"
  • 2007-2009 GT500
  • 2011-2014 Brembo/Track Package
  • 2011-2012 GT500
  • 2013-2014 GT500
  • 2015+ Brembo/Track Package
  • 2015+ Shelby GT350
• Cobra (94-98):
  • Front Caliper: Weight N/A, 1.49". Total area: 3.49
    • Rotor: 13"x1.1", 19.1 lbs
  • Rear Caliper: Weight N/A, 1.49". Total area: 1.74
    • Rotor: 11.65"
• Cobra (99-04):
  • Front Caliper: Weight N/A, 1.59". Total area: 3.97
    • Rotor: 13"x1.1", 19.1 lbs
  • Rear Caliper: Weight N/A, 1.49". Total area: 1.74
    • Rotor: 11.65"
• GT (94-98):
  • Front Calipers: 12.0 lbs, 2.59". Total area: 5.27
    • Rotor: 13.6 lbs, 10.84"x1"
  • Rear Caliper: Weight N/A, 1.49". Total area: 1.74
    • Rotor: 11 lbs, 10"x0.5"
• GT (99-04):
  • Front Caliper: Weight N/A, 1.73". Total area: 4.7
    • Rotor: 13.6 lbs, 10.84"x1"
  • Rear Caliper: Weight N/A, 1.49". Total area: 1.74
    • Rotors: 11 lbs, 10"x0.5"
• S197 V6/GT

 

 

[b.mad@MaddRetros]

After reviewing various brake specs and choices, I decided to go with the caliper that had the greatest piston area and featured a thicker pad, which happens to be the FSL4 Wilwood nickel plated caliper. The purpose of the nickel plated calipers protect from corrosion and wear and it transfers heat out of the caliper body better than powder coat. The caliper also features therm-lock pistons. Therm-lock pistons resist fade and extend service life by reducing the heat transfer into the caliper from the pads. At the time, the car was a daily driver, so I needed a brake pad would be ok in both scenarios.  The Wilwood BP20 brake pad had the highest temp I can find for the street. The Wilwood race kit featured a 12.88" rotor, however, I upgraded to the 14" rotor, which is the GT 72 curved vane rotor. "Wilwood's GT 72 Curved Vane Spec-37 rotors are manufactured from a proprietary iron alloy developed to withstand extreme temperatures with the highest possible degree of resistance against distortion, warping, cracking, and wear. The formulation for this alloy is a derivative of technology and materials that were significant in the development of the extreme duty military spec rotors that are manufactured by Wilwood. Combined with our proven GT Series asymmetrical face slot pattern and individual dynamic balancing, you are assured the smoothest braking available."

Since I wanted to run Wilwood's products, I got their highest temp fluid, EXP 600 PLUS. As you can see, it is top 3 in both boiling points. Please see the list.

Because the FSL4 caliper is thicker, I had to space out the bracket so that the rotor sits in the middle. In doing so, it caused the spindle bracket bolt to NOT have enough thread going through the hole for me to be comfortable. So I bought a longer bolt. Also, because the rubber hose does not connect to the caliper, it will be a good excuse to upgrade to steel braided hoses (and you have no choice).

Tools Needed

• 15mm wrench
• Extra wrench for leverage
• Torque Wrench (In-lb and ft-lb)
• Roll of 0.032" safety wire
• 271 (red) Locktite
• 242 (blue) Locktite
• Rubber mallet/hammer

After you take off the wheels and put the car safely on jack stands, you will need to do the following to remove the factory brakes:

1. Behind the rotor, you will see the spindle and the rear side of the spindle, you will see two 15mm bolts. Take the 15mm bolts and loosen up the bolts. You will need to interlock another wrench to create leverage because it will be difficult to remove.
2. Once the bolts are removed, you will "hang" the caliper so that it does not get damaged. You can use a bungee cord or a metal coat hanger.
3. Once the calipers are out of the way, you remove the rotor. You can wiggle it and it will slide out. However, it can give you a hard time, so take a rubber hammer and tap it a few times.
4. Since the assembly off, it might be a good idea to take off the dust shields and install spindle mounted duct mounts. You will need to drill out the rivets.

To start the installation of the Wilwood kit, you will need to assembly the rotors.

1. 1. Place the rotor on top of the hat and orientate it so that the holes match up.
   2. Use the supplied washer and bolt to join the rotor and hat together.
   3. I recommend that you bolt all the bolts and hand-tighten the bolts. The reason for that is to help make sure the rotor and hat are bolted up correctly to avoid any issues when applying the red Locktite.
   4. Remove one bolt at a time, apply red Locktite, and torque down the bolt to 155 in-lb.  Using an alternate sequence, repeat Step 4 for all bolts.
   5. Next, you will install the safety wire. You will slide the wire through both holes in the head of the bolt.
   6. Using safety wire pliers, you will twist the safety wire.
   7. Using one end of the wire, you will repeat Step 5.

To install the Wilwood Kit, please do the following:

1. If it is installed, you should remove the caliper bridge bolt.
2. You will use the supplied caliper bracket and use the factory bolts to secure it to the spindle.
3. Install the rotor. The rotor has an arrow that tells you the correct rotation.
4. You need to install the appropriate washer onto the caliper mounting bolts. Because the caliper is radial mount, you will slide the caliper onto the bracket. The caliper has an arrow that tells you the correct rotation.
5. You will need to install the brake pads.
6. Verify the fitment. You want the rotor to sit in the middle of the caliper. If the caliper is off-centered, you will need to remove the whole assembly, including the caliper bracket. You will want to install the appropriate washers/shims. The shims should go on the spindle side, as shown below.
7. After the the rotor spacing has been figured out, you will need apply blue Locktite and torque the caliper-spindle mount bolt to 60 ft-lbs. The reason I do not recommend red Locktite is because you won't be able to take it out.
8. Once the caliper bracket has been secured, it is time to figure out caliper spacing for the brake pad contact. You would like to have the brake pad at the edge of the rotor. To achieve this, you will use the supplied caliper spacers.
9. After the caliper spacing has been figured out, you will need to install the caliper bridge. Do not over tighten it, it just need to be tight enough to not have any play.
10.  To tightened the caliper to the bracket bolts, you first install the appropriate washer, then the locking nut. You will need to torque the nut to 30 ft-lb.
11. Next you will need to install the hose. Make sure you route them so that they do not interfere with the wheel and cause it to leak.
12. After that is installed, you will want to refill the brake fluid reservoir, and bleed the brakes. To bleed the brakes, you will need help. There should be one person inside the car to pump the brakes, and the other to open the bleeder. When bleeding the brakes, you will need to start from the rear right tire, then the rear left tire, then the front right tire, and lastly the front left tire.
13. The person in the car will pump the brakes 2 times, and hold the 3rd while the person outside will open the bleeder. Repeat until you have a steady stream of fluid coming out.
14. Repeat for all other tires.

Comparison photos:

Final:

Disclaimer: Madd Motorsports does not guarantee performance improvements or other benefits. All information is deem accurate to the best of Madd Motorsports' ability, however, it is not guaranteed. Madd Motorsports or any company mentioned above are not responsible for any injuries, any damage whatsoever, or for incorrect installation. This is a guide meant to help, it is in no way guaranteed.