Opinions from folks running stock brakes

[johnpinetree]

Hi friends, another question:

Planning on an IRS and while the wilwoods look nice, I'm dead set on running stock mustang brakes. Just seems like for a car that is tipping the scales over 2k lbs stock brakes with good airflow and good pads should work really well. Also planning on figuring out some sort of abs, but I'll leave that for another discussion.

So, from what I gather, the 'stock' options from ffr are 11" fronts circa 99-04, and 11.65" rears from 2015+. Functionally and aesthetically having bigger brakes in the back doesn't sit right. So what are folks doing? Upgrading the fronts to 2015+ with whatever bracket magic that's out there? Finding smaller rears? Parachutes?

Thanks,

Juan

[GoDadGo]

Juan,

If you want to Stock Style Larger Front Brakes, then I think you can upgrade to the Mustang Cobra setup which would give you a much larger 13" Rotor if it bugs you.
Since I am not sure what guys are running, I'd check with Factory Five or one of the Professional or Master Hobbyist Builders before ordering.

https://lmr.com/products/03-04-Cobra-Brake-Upgrades

I'm running the Stock GT/Base Mustang Brakes on the front with Ford Explorer Brakes in the rear which gives me very similar size brakes on my 3-Link solid axle.
Hope this helps, but remember to double-check my recommendation because like you, I am a hobbyist builder too.

Steve
https://www.factoryfive.com/whats-new/customer-steve-l-graduates-his-mk4-roadster/

[wallace18]

Hi friends, another question:

Planning on an IRS and while the wilwoods look nice, I'm dead set on running stock mustang brakes. Just seems like for a car that is tipping the scales over 2k lbs stock brakes with good airflow and good pads should work really well. Also planning on figuring out some sort of abs, but I'll leave that for another discussion.

So, from what I gather, the 'stock' options from ffr are 11" fronts circa 99-04, and 11.65" rears from 2015+. Functionally and aesthetically having bigger brakes in the back doesn't sit right. So what are folks doing? Upgrading the fronts to 2015+ with whatever bracket magic that's out there? Finding smaller rears? Parachutes?

Thanks,

Juan

We used this" Stock" setup on a 427 MK4 build I did a while back. Bill has many happy miles with this setup with no issues.

https://thefactoryfiveforum.com/showthread.php?21008-Bill-amp-Laura-s-MK4-build-thread

[Joel Hauser]

I used the stock front and rear calipers off my 1996 mustang gt donor, along with basic OEM (cheapo) pads and discs. I did not use the master cylinder from the mustang because it does not fit. The folks at factory five told me to use a MC for a 1987 to 1993 mustang; I'm using a Dorman M93637. I had to modify the MC push rod, but can't remember why. I do not have a booster. Even though the car is very light, the pedal requires a LOT of pressure. However, I'm getting used to it, and I have complete confidence in the brakes. I think I just never bedded the brakes, so with use they have gotten better. When my pads wear out - in about 10 years - I will buy better pad with a higher coefficient of friction, like the Hawks others are using.

[nuhale]

I can only speak from my setup as I have not experinced one other than mine. I bought my build 2nd hand and already had the "stock" mustang setup. As far as teh 2015+ rears that's not the case for mine. I have the same era rears... not 100% on rotor dia front to rear but I thought they were same. Note that I have early MKIV with old IRS setup. Maybe the rear design changed with the new IRS.

I considered upgrading to wilwood but as I had everything already I opted to go with a power assist Hydroboost from Mike Forte and the "stock" setup. This came with some challenges along the way but was able to overcome and it's working quite well. I did install a proportioning valve to have adjustability front to rear. I understand that these cars need a little more rear given weight and balance.

I have 1500 miles on 7275 and had some "panic stops" along the way. Car ALWAYS stops on a dime without any issue. My primary use is a street toy so can't speak for track.

[rich grsc]

Hi friends, another question:

Planning on an IRS and while the wilwoods look nice, I'm dead set on running stock mustang brakes. Just seems like for a car that is tipping the scales over 2k lbs stock brakes with good airflow and good pads should work really well. Also planning on figuring out some sort of abs, but I'll leave that for another discussion.

So, from what I gather, the 'stock' options from ffr are 11" fronts circa 99-04, and 11.65" rears from 2015+. Functionally and aesthetically having bigger brakes in the back doesn't sit right. So what are folks doing? Upgrading the fronts to 2015+ with whatever bracket magic that's out there? Finding smaller rears? Parachutes?

Thanks,

Juan

What are you talking about:confused: Do you want the car to stop or not? You have to have more brakes on the rear of these cars than on a conventional car, they are weight biased to the rear. If you put smaller brakes on the rear, and you are going to have a very hard time with even, controlled braking. The more rear brakes, the faster it'll stop.

[Gumball]

My build was originally going to use the FFR 17" wheels, so I had the brake set-up that was OEM for the Mustang Cobra - 13" front and 11.65" rear. But, early in the build, I decided to go more period correct and wanted to use 15" wheels. The 11.65" rears work fine with those wheels, but the 13" fronts wouldn't fit. My solution was to buy an unused set of the OEM late-SN95 front brakes with the 11" rotor and twin-piston calipers from someone who wasn't using them from their complete kit.

My car now has nearly 17K miles on it and I find the brakes very effective. Even though I'm using the SN95 master without a booster, distribution block, or bias valve, I have no problem with effort or front/rear bias. Overall, I'm very happy with my brake setup, as is.

As for aesthetics, the roughly half-inch difference in rotor diameter on the rear is imperceptible through the FFR 15" wheels - both front and rear rotors will the area behind the spokes well and with proportion.

[jcrumpley]

Hi friends, another question:

Planning on an IRS and while the wilwoods look nice, I'm dead set on running stock mustang brakes. Just seems like for a car that is tipping the scales over 2k lbs stock brakes with good airflow and good pads should work really well. Also planning on figuring out some sort of abs, but I'll leave that for another discussion.

So, from what I gather, the 'stock' options from ffr are 11" fronts circa 99-04, and 11.65" rears from 2015+. Functionally and aesthetically having bigger brakes in the back doesn't sit right. So what are folks doing? Upgrading the fronts to 2015+ with whatever bracket magic that's out there? Finding smaller rears? Parachutes?

Thanks,

Juan


My stock mustang brakes work fine using as manual brakes with wilwood pedals. I am using the 13 inch cobra front brakes from SVE and using the 13 inch in the rear on the IRS. Some IRS mustangs came with 13 inch in the rear so you can easily source those. Clearance on the rear caliper is close and you have to use at least 17 inch wheels. I am using the stock mustang IRS caliper mounts and not using any of the factory five IRS caliper mounting parts. I also added the remote wilwood brake bias adjuster, but it is not needed once you get the bias correct. You can experiment with different size brake master cylinders to get the fell you want. My pedal is very solid with a medium amount of pressure applied. It stops very well. You may have to alter the emergency brake parts if you use the original rear IRS mustang caliper mounts. I custom made mine.

[johnpinetree]

Thanks for the quick replies!

For clarification I think this is an IRS-specific thing: earlier gen mustang brakes in front and bigger, latest gen brakes in rear.

[johnpinetree]

My build was originally going to use the FFR 17" wheels, so I had the brake set-up that was OEM for the Mustang Cobra - 13" front and 11.65" rear. But, early in the build, I decided to go more period correct and wanted to use 15" wheels. The 11.65" rears work fine with those wheels, but the 13" fronts wouldn't fit. My solution was to buy an unused set of the OEM late-SN95 front brakes with the 11" rotor and twin-piston calipers from someone who wasn't using them from their complete kit.

My car now has nearly 17K miles on it and I find the brakes very effective. Even though I'm using the SN95 master without a booster, distribution block, or bias valve, I have no problem with effort or front/rear bias. Overall, I'm very happy with my brake setup, as is.

As for aesthetics, the roughly half-inch difference in rotor diameter on the rear is imperceptible through the FFR 15" wheels - both front and rear rotors will the area behind the spokes well and with proportion.

Really great data point, Chris thanks!

One more question, how does the pad surface area compare between the front and back?

[NAZ]

Hi friends, another question:

Planning on an IRS and while the wilwoods look nice, I'm dead set on running stock mustang brakes. Just seems like for a car that is tipping the scales over 2k lbs stock brakes with good airflow and good pads should work really well. Also planning on figuring out some sort of abs, but I'll leave that for another discussion.

So, from what I gather, the 'stock' options from ffr are 11" fronts circa 99-04, and 11.65" rears from 2015+. Functionally and aesthetically having bigger brakes in the back doesn't sit right. So what are folks doing? Upgrading the fronts to 2015+ with whatever bracket magic that's out there? Finding smaller rears? Parachutes?

Thanks,

Juan

If you are thinking of adding ABS you should start looking at how others have added ABS before you get too far along on planning: https://thefactoryfiveforum.com/showthread.php?38573-ABS-success!

Let me correct you on what you are referring to as "stock brakes" -- these are not stock, what you descried are two different sets of rotors and calipers from two different years of Fords. This is not semantics, those two cars have engineered brake systems specifically to these two cars and unless someone using these particular OEM components together in the same car as yours has done the leg work, you will be experimenting. If you don't have the knowledge, skill, and experience designing brake systems you will be at a disadvantage. If this combo of components has worked for others you may be OK using them for your car but be cautious about straying too far from proven systems. If you do want to design your own system, here's a calculator that may help you: http://brakepower.com/index.htm

But I'll also add that before you try to combine a bunch of components together you should study everything you can about brakes systems in general as there are many misconceptions about how brakes work.

[Fman]

One other option with GT stock brakes is to upgrade to power stop slotted and drilled rotors and better pads. I ended up doing this, with only 25 miles on my go-kart I can't really give you a true long term brake experience. What I can say is testing the brakes at 30-40 mph with some hard stops it has had no issues. I think for around town weekend cruise driving the GT brakes will be fine, if I were going to be tracking the car I would have gone with the Wilwood upgrade. And you can always add Wilwood later on down the road if you feel like you need better stopping power.

Front kit:
https://www.summitracing.com/parts/PWR-K1301-26

Rear kit:
https://www.summitracing.com/parts/PWR-AR-85160XPR

[johnpinetree]

Thanks NAZ, I'll do some more research this weekend. I hear what you're saying and appreciate your input.

After five minutes on the brake power website I'm starting to realize I need to do a deep dive... the plus side... this is exactly why I want to build a flipping car! This is great!!

[CraigS]

The oem brakes that come w/ a salvage 2015 rear suspension are great. Much, much better than the old Mustang rear brakes. The old stock system always had way to little rear brake capacity so the 2015+ brakes help a lot. You could use the larger fronts mentioned by jcrumpley. They may look a little more normal but they are not needed at all. Another advantage of the 2015 IRS brakes is that the parking brake works very well.

[Fixit]

I looked at it from two aspects:
1) The Mustang brakes were designed to stop a car twice as heavy, and you have the reliability & parts availability of a huge manufacturer.
2) Couldn't justify $3000