I have all the parts to do the ATS Brembo fronts(mounting kit, calipers, slotted rotors, stainless lines, pads etc) and was wondering if there was an upgrade for rear besides rotors and pads...please keep us posted
Installing ATS Brembos on the Cobra.
- Thread starter GodStang
- Start date
Won't work for me, I have a fox body and run vacuum brakes.
With the vacuum boosters, there are different bore diameters to account for the difference in various piston sizes.
So for instance, my current brake setup mimics what comes on any 99-04 Cobra/Mach/Bullitt. 2-piston front calipers with 40.5mm pistons and the 38mm rear calipers. Total caliper surface area of 7420mm^2.
Now, swapping to the ATS brembos with 42mm pistons, and the Taurus 43mm rear calculator gives you a total piston surface area of 8446mm^2.
That's a surface area increase of roughly 14%
With the same MC, your stroke will increase, and pedal effort will decrease. Way to compensate is to increase MC bore diameter by a similar ratio.
Looking online at parts store sites, I see there are a few different bores for the 96-04 hydroboost setup. A 1", 1 1/16" and a 1 5/8" bore. I'm unfamiliar with what models come with bore sizes however.
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Took the caliper off the car to get more pics and see if the pad was fully seated on the piston. It does.
Red bracket is my standard SN95 cobra pad bracket. Pads and rotor are SN95 cobra. Only thing I swapped was the bare cast iron caliper in the photos.
While I haven't hooked up the parking brake, it's the same physical setup
Red bracket is my standard SN95 cobra pad bracket. Pads and rotor are SN95 cobra. Only thing I swapped was the bare cast iron caliper in the photos.
While I haven't hooked up the parking brake, it's the same physical setup
Is there any danger posed by not upgrading the m/c? It seems like the amount of pedal travel needed to stop the car will increase. Does that mean that it won't have enough travel to fully stop the car in a panic situation?
There's a discussion about this on another forum I'm on. The general consensus is that it would be ideal to change the master cylinder to keep the ratio between the pistons the same.
But.... I have Baer 6P calipers and didn't notice any real difference in pedal throw. And I haven't had any problems stopping quickly when needed.
The ratio of master cylinder to slave cylinder (the Caliper pistons) has a direct impact on pedal feel, lenght of travel and sensitivity.
It’s equivalent to leverage. If you increase the lever (by making the Caliper area larger and keeping MC the same) your stroke becomes longer (pedal travel distance) but your work is less. The main issue is running out of pedal travel by hitting the firewall before you’ve activated the brakes to max potential.
I don’t think that’s the case here. It’s not a significant increase in Caliper surface area, but it is an increase so it’s something to be mindful of.
Question I posed earlier was what is available in terms of oem hydroboost MCs to select from?
I can’t really help much there as I’m running vacuum booster brakes. But I calculated out I only needed to go 1/16” larger in MC bore with the ATS brembos and 43mm taurus rear calipers. That’s not a huge difference in MC bore size
As far as hydroboost Master cylinders I believe there are only 2 that are O.E cheap, 1 inch and 1-1/16th.
With that said I just checked Bear brakes and they now offer hydroboost 1-1/8 bore units but they are pushing $400, see the link below. As far as I can tell these are the only aftermarket hydroboost units available to us.
Totalling all this up I get about 11-1200 dollars depending on where you source your parts and whether you buy inserts or not. Not bad but I wonder how this setup compares to others on the market? Still doesnt sound bad when you compare the actual contents of the kits out there because you're only getting front calipers and rotors in most cases.
Baer Performance Brake Systems, Rotor Upgrades, pads and Aftermarket Automotive Components
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Thanks for the info, guys. I have new ATS calipers, the insert kit, and rebuilt rear calipers to put on after Christmas. I'm at $700 for new front and rear calipers, pads, hardware, offsets, machining and painting. If you don't do the rear, you'll have $550 in the whole kit. @Mustang5L5 will I still use the Cobra brake pads in the rear with the Taurus calipers? I think I remember the difference between GT and Cobra setups being thinner pads to accommodate thicker rotors.
Yes, still using cobra pads and rotors
@Mustang5L5 what size do you think you is needed?
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Problem is I can't find accurate info as to what bore size goes to what year and brake setup. Plenty of info on the vaccum boosted setups, but for hydroboost the info just isn't available.
I also see two sizes listed. A 1" bore, and a 1 1/16" bore.
I *think* the GT with the larger front calipers (larger by way of dual 44.5mm pistons) used the 1 1/16" bore, and the cobra used the 1" bore. Unconfirmed though. SO really this is step one to ID years and bore sizes to what brake combo.
If that is the case, I would swap the cobra 1" to the 1 1/16" with the ATS and 43mm rear calipers. How easy is that to do? Unknown. Ford has a habit of swapping around fitting sizes to prevent MC mixup on the factory line. May not be a direct swap without adapters of some sort.
This is uncharted territory really. Someone's gotta be the first to try it and figure out what works and what doesn't. Seems like we are still brainstorming ideas to figure out a good, safe combo of parts to use here.
But for the vaccum boosted guys (94-95 cobra and fox guys), I think the ATS fronts, 43mm rears and a 94-95 1 1/16" bore MC is the combo to use and what I will be trying out on my car.
If you shop for an 03-04 Cobra MC the one that comes up for it is 1 1/16". Not saying that is stock sizes though. The 96-98 GT is the 1".
I've seen info stating that all the V8 99-04 cars had a 1-1/16th master and the V6 cars had a 1in. But I've also found other info stating that all 99-04 cars came with a 1-1/16th Master cylinder.
When I look at LMR they only list the master for the V8 cars and state that it's a 1-1/16th. No mention of the V6 setup though.
If I get chance today I'll do some cross referencing and see if I can figure out if there is a difference between the V8 cars and V6s.
It does look like either way if you have a 99-04 V8 car you should have the larger master.
V6 cars have vacuum brakes. They do use the 1” bore MC.
One thing to keep in mind is pedal geometry changed slightly in 1996, so that plays a role. That’s why you can’t look at what I figured out for the vacuum brajes and apply it to hydroboost.
I think you need 1/16” more MC bore. But I’d hate to have someone buy a $400 aftermarket MC to try this out.
Has anyone officially tried out the ATS front/43mm rear setup with oe master cylinder?
One thing to keep in mind is pedal geometry changed slightly in 1996, so that plays a role. That’s why you can’t look at what I figured out for the vacuum brajes and apply it to hydroboost.
I think you need 1/16” more MC bore. But I’d hate to have someone buy a $400 aftermarket MC to try this out.
Has anyone officially tried out the ATS front/43mm rear setup with oe master cylinder?
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I'll know in the next week or two. I have all the parts here, I just need to paint and assemble. I'll do some very subjective testing immediately before the swap and report back.
Sorry I am little confused here.
So are you saying that for us hydroboost guys you think we need a 1-1/8 master cylinder?
From what I've found on both rock auto and tasca ford websites all V8 cars use the same part number master cylinder that has a 1-1/16th bore. Adding another 1/16th would obviously take is to 1-1/8th which is aftermarket territory.
I'm unsure. I think so, but hydroboost is strange because when I owned my 2003GT, I installed 2003 Mach 1 front brakes, and never touched the MC. Car stopped great and I even autoXed that car and pushed those brakes hard. If the MC was "wrong", I never knew it and the car never showed it. The GT calipers were 20% larger than the Cobra versions and the MC handled that fine. Keep in mind, those 99-04 GT calipers are using 44.5mm pistons as well.
Hydroboost seems to be a lot more forgiving. Whereas the vacuum cars seem more sensitive. I've had a number of brake setups on my Fox and have changed the MC three times to compensate. Each time was 1/16" of a difference, and each time it made a HUGE difference in pedal feel and stroke.
So sorry if I seem rather incomplete, but I don't want to give out any info as "matter of fact" unless I am 100% it is in fact true. So in this case, I do not know. I am speculating.
After checking multiple sites I am now 100% sure all V8 99-04 cars use the same 1-1/16th master cylinder. Every site shows the same part number for GT, Mach1, Cobra and even the Bullitt. So you had the correct master cylinder when you upgraded to Mach1 calipers.
I wish there was more information out there regarding hydroboost setups so I could understand everything better and contribute more. I find it interesting that things seem to change so much with vacuum assisted brakes over hydroboost assisted brakes. If my car were running I'd love to find a way to help out.
I totally understand where you're coming from and appreciate the work that you're doing for all of us. I wouldn't want to put something out as fact at this point either. Lastly I appreciate the fact that you have faced the bias issue head on instead of telling people "it's fine" or "it's just like the Cobra R brake setup".
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Is there a list of the all the offsets that fit? I got my brakes on today only to discover that my wheels rub. It looks like I'll need a 3/8 spacers to clear. Not bad but if the wheels poke out a lot, I'll be annoyed
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