I've been on this forum every night for months trying to get my ducks in a row for my future build. I picked up a donor Mark VIII for 4.6 DOHC with 80k on it on the cheap and plan on using the IRS. I'm planning power steering and manual brakes.
99 GT Rotors and calipers up front and using the Lincoln rear brakes.
I've read about the MC options and it seems like many are using the 84 jeep or 94 Cobra setups.
Question is are people happy with this manual setup or is the larger Cobra brakes front and rear worth the extra cost? Anyone run into clearance problems with standard width IRS and 17" wheels and 99 cobra calipers? I guess Hydroboost isn't totally out of the question but i like the idea of manual brakes.
This car will be built for weekend cruising and some hard pulls every now and then.
I have a 4 piston Wilwood set up for the IRS. It is by far the best brakes available for it.
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Thanks Gordon. I'm sure many builders before me have said this but I plan to build my car and pass it on to my children when my time is up. The Wilwood Sets work and look great from what I've read and would be a great upgrade down the road, but I'm looking to start off on shorter budget.
I started out building a fun street car. I used standard T-bird brakes on the rear, and Fox calipers in the front. Brake pads were Hawk HP-S. I also used a manual dual MC.
For the street, I thought the brakes were excellent. Easy to modulate, and you could lock them up at speeds under 40 if you weren't carefull. I wouldn't hesitate to use stock brakes on a street car.
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.boB
Dart 427W, Momar 8 Stack EFI, 600'ish hp, TKO, 3.55 TruTrac, Red with Ghost Flames. More fun than should legally be allowed. http://home.comcast.net/~bobcowan035/site/
Most of the discussion on using stock brakes isn't centered on the cost. We all know they are a bargain, hands down. The main issue is balance. Some have no problem with the small single piston rears. Others who have stressed them on the track suggest they aren't the optimum choice. The trend there is to use calipers of a similar size as the front, because the weight distribution on a roadster is 49/51, unlike the donor at 65/35.
Once you start looking around for a rear caliper, the e-brake issue comes up. It doesn't seem to have an easy off the donor answer yet in a bigger caliper. Most use the internal drum set up, which isn't preferred. We'd like the lever acting cable set up. Wilwood offers an additional spot e -brake, which adds cost and complexity.
What we might prefer is a dual piston factory rear caliper with e-brake built in, and we haven't seen it - yet.
99 GT Rotors and calipers up front and using the Lincoln rear brakes.
Question is are people happy with this manual setup or is the larger Cobra brakes front and rear worth the extra cost? Anyone run into clearance problems with standard width IRS and 17" wheels and 99 cobra calipers? I guess Hydroboost isn't totally out of the question but i like the idea of manual brakes.
No problems I've heard of on wheel clearance, the bigger problem is the size of the Mustang rear pistons, better off with T-Bird / MkVIII calipers in rear, but you're still going to need some bias.
The guy who started the linked thread ended up integrating '94-'95 ABS to get the brakes working right. You can search his threads for the details on that (ABS).
In the linked thread pay attention to the challenge series guy (about page 5) who says he could outbrake anything on track except for cars with rotors the size of garbage can lids. With most any stockish rear calipers you're going to need dual master cylinders, 3/4" to the front, 5/8" to the rear. A little bit of a heavy pedal (modify the stock pedal to get ~6:1 ratio), but it'll jerk your eyeballs loose (with the brakes) if you want to.
Somewhere about page 10 or 11, someone lists a part number for a stockish master cylinder that has bias built into it. Maybe that's right, maybe it's wrong, but you're definately going to need to do something about brake bias if you want it to stop quick with stock rear calipers...
If you don't build some bias in expect to lock down the front.
I started out building a fun street car. I used standard T-bird brakes on the rear, and Fox calipers in the front. Brake pads were Hawk HP-S. I also used a manual dual MC.
For the street, I thought the brakes were excellent. Easy to modulate, and you could lock them up at speeds under 40 if you weren't carefull. I wouldn't hesitate to use stock brakes on a street car.
Same with me, same setup and I have complete confidence in my brakes.
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Good move on the power steering and manual brakes, that's what I have and love it. I'm running Mustang Cobra brakes all around, perfect. They also look good too.
Good chance this will not matter, but what wheels are you planning? 17's probably don't matter. If you go with 15's it might rule out some brake setups - especially if you are using true pin drives.
Please ignore this if you have already made plans, but if you are planning on using the MK VIII spindles, make sure they will fit. The IRS is setup for the TBird. I figure you probably have already planned for this, but just in case.........
Now back to your brake question :-)
I went with the brakes off of a 2001 Mustang Cobra with 17" Vintage pin drive wheels. I replaced the rear hubs in the TBird spindle with the Cobra hubs so I could us the factory braking system with no modifications (for ease of maintenance), hydroboost power brakes. I have had no issues with braking performance on the street.
Good luck and welcome to the fun!!
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My opinion on the matter is that rotors and calipers are not going to make any difference for street driving, so I would use donor calipers and rotors. The master cylinder diameters, I feel, is what is crucial to having a proper working system.
As MikeKelly wrote; 3/4'' front and 5/8" rear on a dual mc set up. A brake balance bar is great to proportion the effort front to rear perfectly.
I had the jeep mc (7/8") then changed to willwood pedals, dual mc w/balance bar when my body was off to paint. Great example of why going cheap will cost more in the end.
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Stock TBIRD and FOX front do work well, but Gordon's stuff works and looks way better, (Big bucks and ego)!
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Last edited by Bill Hughes; 07-23-2012 at 02:08 AM..
MikeKelly- Thanks, that thread was very helpful. A member spoke about using a Ford Tempo MC that had dual diameter pistons that worked with his hydroboost setup.
I love the idea along with using my Mark VIII rear calipers.
Anyone know is the same MC would bolt right up without the hydroboost or if there any other MC's that having dual diameters built in? I tryed a search but didn't come across anything.
I looked up an 85' MC on a parts site and it looks like it would work w/ out hydroboost....
My front calipers and brake pads are 40% larger and my rear kits are 4 piston while FFR sells a single piston rear kit.
__________________ gordon@levyracing.com Pro Builder and Go Fast Specialist
99/2000 NASA PSO Champion in a FFR
2005 FFR Challenge West coast Champions 2nd 2005 Nationals Sponsor for Tony B. ST-2 National Champion 2007
2009 TTC runner up-2010 TTB Runner up
Over 155 Turnkey FFR's in 16 years and still counting
A member spoke about using a Ford Tempo MC that had dual diameter pistons that worked with his hydroboost setup.
Anyone know is the same MC would bolt right up without the hydroboost or if there any other MC's that having dual diameters built in?
1- Your problem with that master cylinder / manual brakes / stock rear calipers is probably going to be tha master cylinder piston diameter. 7:1 is about the most mechanical leverage you can build into the brake pedal and still have enough travel to actuate the master cylinder (6:1 is more common). It takes about a 5/8" master cylinder to get enough line pressure on the (stock) rear calipers to do the job with a manual pedal.
2- So, yes, it would probably bolt up without hydroboost, but master cylinders built for power brakes typically are not going to have piston sizes that are going to work for manual brakes (in this application). The result would be a really hard pedal that requires more force than you can apply to stop the car (power master cylinder using a manual brake pedal setup, no booster).
I do not know what the piston sizes are in the Tempo master cylinder, but I suspect they're too big to use a manual pedal with.
It looks to me like the bias ought to be close, but I don't think anybody would ever be "happy" with it on a manual brake pedal (pistons too big).
Certainly shows some potential for a boosted system - be careful not to get the back end locking up before the front. I *personally* don't think you'll ever get good control of the bias without side by side master cylinders operated off an adjustable balance bar.
If you end up with the back end locking up first and no way to adjust it you've created a dangerous car (prone to snap spin under braking, it's a very bad thing, ask Ricky Rudd).
The thing to keep in mind here is that the Roadster was designed around Fox components which worked good. Over time all manner of parts have been thrown at the brake system, some of which worked great, some not so great. I would suggest sticking with a known combination rather than trying to break new ground with another permutation of parts Ford branded or otherwise.
I have '90 T-bird rears, Lincoln LSC fronts ( same as Fox but gives you 5 lug plus a 73MM caliper for better brake balance) and a 1984 Jeep master cylinder with Porterfield R4s pads. Nice pedal feel, car stops great and is easy to modulate on the street and track. Neither power assist nor a proportioning valve is needed with this.
HTH
Frank
PS: FWIW I don't know how locking up the brakes ever got to be a measure of brake performance but a good brake system is one that stops the car quickly and evenly without locking the brakes. When the brakes are locked you're toast.
I would suggest sticking with a known combination rather than trying to break new ground with another permutation of parts.
+1
Looking at the 20mm / 28mm (non-adjustable) bias of the Tempo MC worried me - boost it and you've got enough pressure, but what happens with the GT rear calipers, what happens with the larger pistoned Tbird / MkVIII rear calipers? Which calipers on the front? What pads? What rotors?
Too many variables - it's got potential but you'd have to do your own testing on a case by case basis - and be very wary of getting too much going to the rear.
Mike
Quote:
Originally Posted by Frank Messina
P.S. I don't know how locking up the brakes ever got to be a measure of brake performance
I don't know how locking up the brakes ever got to be a measure of brake performance
After thinking about that question I believe it originated (on this forum) from FFR builders who tried putting unmodified power brake pedals behind unboosted power brake master cylinders (or some combination thereof) and were not happy with how their brakes worked.
PS: FWIW I don't know how locking up the brakes ever got to be a measure of brake performance but a good brake system is one that stops the car quickly and evenly without locking the brakes. When the brakes are locked you're toast.
It's actually pretty simple. Think of it like your traction budget, but narrow it down to straight line traction vs. brake function. Straight line traction is trying to keep the tire rolling along the pavement. Brake function is trying to stop it.
If you can lock up the tires, that means you have more brake function than you have traction budget. If you're a good driver, you have everything you need for threshold braking. Bigger/better/stronger brakes will probably not help you much; and might even be dangerous . Considering the tires most people put on these cars - even with the light weight - that's pretty good brake function.
To safely bring the vehicle to a short and safe stop requires careful brake modulation - either by computer or by driver's foot. But if your brakes are not good enough to bring you close to that razor edge, you'll end up with an extended stopping distance.
And, you're right. Once the tires lock and you begin to slide, you've relinquished all control and you're just along for the ride. That's where brake modulation comes in.
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.boB
Dart 427W, Momar 8 Stack EFI, 600'ish hp, TKO, 3.55 TruTrac, Red with Ghost Flames. More fun than should legally be allowed. http://home.comcast.net/~bobcowan035/site/
Thanks for the lecture Bob, but I actually understand how it works believe it or not. The point I was trying to make is that merely getting the tires to slide, which in the case of rock hard BF Goodrich Radial TAs for example is pretty easy to do, does not tell the whole story about a braking system. I'll just leave it at that.
Sorry, Frank, didn't mean to lecture. I spend a lot of time teaching complicated subjects, so I tend to break things down to simple levels - which is way below your level.
What I meant to say is that if you can lock up the tires, you either have too much brake power, or not enough traction. I vote for the latter.
__________________
.boB
Dart 427W, Momar 8 Stack EFI, 600'ish hp, TKO, 3.55 TruTrac, Red with Ghost Flames. More fun than should legally be allowed. http://home.comcast.net/~bobcowan035/site/
Sorry, Frank, didn't mean to lecture. I spend a lot of time teaching complicated subjects, so I tend to break things down to simple levels - which is way below your level.
What I meant to say is that if you can lock up the tires, you either have too much brake power, or not enough traction. I vote for the latter.
I guess to state it a different way...
If you can lock up the tires you need more traction (better tires). If you can't you need more braking ability (better brakes). Usually money will be the limiting factor in this back-and-forth.
Wouldn't the largest components of being able to modulate the brakes be a longer brake pedal travel and/or master cylinder sizes? That would allow you to make the smaller inputs and adjustments to maintain maximum braking on the edge of locking them up?
What I meant to say is that if you can lock up the tires, you either have too much brake power, or not enough traction. I vote for the latter.
Quote:
Originally Posted by JeepFlyer
I guess to state it a different way...
If you can lock up the tires you need more traction (better tires). If you can't you need more braking ability (better brakes).
*My* answer is no, no, no.
The brake pedal should *easily* work better than the happy pedal in these cars (especially when you're talking "street"). It's a 2200# car (with huge tires) and the commonly employed brake components work right in cars that weigh a lot more. You very rarely hear anyone on this forum complaining about the happy pedal, but the "brake problem" threads number in the dozens (hundreds???).
These cars will stop plenty fast when you get all four wheels braking, but all the potential combinations of brake components make that pretty easy to get wrong.
And different drivers have differing expectations of the brakes. Some will rarely (if ever) pile on the brakes hard until they get in a bad situation (may never happen).
The bottom line is the cars will stop really, really fast if you get the components working together right. They won't stop at all if you put the wrong pedal or master cylinder in it, and that's where *most* of the brake problem threads seem to lead.
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