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Thread: Question on 33 Hot Rod Brakes

  1. #1
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    Question on 33 Hot Rod Brakes

    I have ffr 33 hot rod kit completely built with the ff front suspension and duel piston calipers on front that came with the kit. I'm running a 94 mustang 8.8 rear end with single piston calipers. The brake pads & the rear rotors are after market non vented. The system is total bled out. The brake pedal is nice & hard. First time out for a road test the car would take the length of a football field to stop at around 40 mph slowing down gradually. I understand that the car has no power brakes and I understand that the brake pad and rotors have to brake in. But I have put 20 miles on these pads and rotors and they're still reacting the same. Before I spend the money to go Brembo brakes. If anyone has had this problem and has corrected it or has any suggestions please email me . Thank you

  2. #2
    EFI Rules and Carbs Drool Arrowhead's Avatar
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    No, your not the only one to have concerns about the brakes. There are a couple of things you can do to make them better. Since there are dual master cylinders, Wilwood reccomends bleeding the front and rear at the same time. This allows for full pedal travel and complete evacuation of any air. If you try to bleed only one at a time, the other cylinder will limit the stroke as the pressure builds. You can also play with the balance bar to get more pressure to the front or rear of course. Some builders have opted for some aftermarket rotros and pads from powerstop. Complete front and rear sets can be had for under $200 from ebay. The rotors are cad plated so they will stay looking good and the pads will give you additional bite. It's alo import to bed the pads properly so that some pad material gets transferred to the rotor for additional grip.

    There has also been discussions about master cylinder size, but I'm not sure if anyone has tried to change on or both.

    (How'd I do Dr Ruth? Inside joke)
    Last edited by Arrowhead; 02-29-2012 at 10:20 PM.

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    Senior Member ehansen007's Avatar
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    I had the same issue. Even asking Wilwood, all they could say is "well, pedal pressure is not your problem." The biggest culprit is master cylinder size. Front should be .700 for the front and .625 for the rear. Try this first as it's the least expensive. Then if that doesn't do the trick, order these from ebay. http://www.ebay.com/itm/FRONT-REAR-K...item3371cc6c6c

    They are great and really did the trick. They also look better. I even tried some Hawk pads and they do not perform as well as those included with the rotors. Best of luck!

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    Junior Member bretts33's Avatar
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    Just wondering why FF5 doesnt put the correct master cylinder piston size for the kit they are supplying? I can see an argument that says FF5 has no control of what brakes builders put on the rear but why do they continue to provide front masters that dont match the calipers they are supplying? Does anyone know what size the rear MC is that comes with the kit?

  5. #5
    EFI Rules and Carbs Drool Arrowhead's Avatar
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    They are both .75" master cylinders - at least they were. I heard a rumor that they were going to change the rear to .625, but have not heard from any of the newer builders to conform that.

    Erik,

    Have you made the switch and it made an improvement?

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    Member stang_killer's Avatar
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    ok, I have to ask. I have chassis built and getting close to putting body back on. I have 13" cobra fronts with vented/slotted rotors and Cobra calipers, Also running cobra brakes in rear with vented/slotted rotors. I have the stock masters installed. pedal is rock hard. I dont have a place to gokart and test brakes. Should I change the masters? Now is time with no body in the way.

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    Senior Member ehansen007's Avatar
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    I personally did not do this however I spoke to Robboy in Florida and he said it's much, much better. And he's an accomplished auto crosser who's building a wicked 33 for that purpose. I'm only wish I had done it with the body off. I'm also willing to bet that the .750 is a just a generic MC that they put in most of their kits with that pedal box but I'm not sure.

    But again, don't let pedal pressure fool you. Put the right MC's in there and check. I bet you get better modulation and feel through the smaller diameter MC's. And, for another $150 for pads and rotors, I bet you have a pretty good setup.

    FYI, for the ebay kit, I autocrossed this weekend (see video post in the forum) and had decided to try the Hawk pads to see if I could get more bite out of the front. Turns out the pads that come with the ebay kit are best with those rotors so some research was done at some point. Those hawks had me almost blowing through the exit! I'm heading to the garage to switch them back!

    Erik

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    Member stang_killer's Avatar
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    ok, I may drop to the .7 and .625 for rear. I will see how the pads I have now are with the cobra rotors. they are drilled and slotted. Have ceramic pads for cobra setups not the stuff that came with kit. In fact have front rotors, calipers and pads to sell off. Waiting until I am done to do a garage sale of unsused parts. $100 for masters sucks but way easier to change now then when I have body back on. I did install the remote bias adjuster and have it hidden in my console. I know based on pedal effort with clutch that the smaller masters will give better feel with less pedal effort.
    Last edited by stang_killer; 03-01-2012 at 03:40 PM.

  9. #9
    EFI Rules and Carbs Drool Arrowhead's Avatar
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    I already have the Powerstop pads and rotors. Back when I was looking into changing master cylinders about a year and half ago, there were only a couple sizes available in the exact style required to fit in that pedal box, but I think thay added some sizes since.

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    Senior Member ehansen007's Avatar
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    Quote Originally Posted by stang_killer View Post
    ok, I have to ask. I have chassis built and getting close to putting body back on. I have 13" cobra fronts with vented/slotted rotors and Cobra calipers, Also running cobra brakes in rear with vented/slotted rotors. I have the stock masters installed. pedal is rock hard. I dont have a place to gokart and test brakes. Should I change the masters? Now is time with no body in the way.
    Okay, You may be okay Stang killer. The .625 would work well if you've got the stock GT rotors (10.5) with the single piston calipers on back but if you've got the Cobras, with the 11.65 rear rotor and single/dual piston, you've got more volume so you're probably good with .750. I bet same goes for the fronts. Sorry for the runaround. I was more focused on Terry P's application. It looks like the Factory five upgrade kit are 11.65 cobra rotors as well so maybe that's why they just go with the .750s.
    Last edited by ehansen007; 03-01-2012 at 04:20 PM.

  11. #11
    Director of R&D, FFR Jim Schenck's Avatar
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    The 3/4 front master cylinder is a good match for the 2 piston aluminum front calipers that come with both the 33 and the MKIV, I wouldn't change that unless you have matched all your other components and are still not happy. The rear 3/4 works fine for the T-bird calipers (which have 45mm vs 38 for the mustang) and for the Wilwood rears, but is not as good a fit with the Mustang GT or SVT brakes as would be a smaller 5/8 master. We have been looking into re-sizing the rear as the mustang brakes have now eclipsed the T-birds in terms of popularity, but there still is not one perfect size that will work for everyone. If you are using the Mustang brakes and are not happy with the pedal effort I would switch just the rear master to 5/8 and try it before doing any other changes. Also try autocross type pads that heat up quickly for a good street pad for our cars since we are light enough to not overwork them, something like a Carbotech XP-8 compound is what I like for a street car.

    Erik,
    For your Hawks it could be you don't get enough heat in them during a short autocross run, they might not be so bad if you are going to an open track type event.
    Jim Schenck
    Factory Five Racing

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    Junior Member bretts33's Avatar
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    I just got off the phone with Willwood. His comment was that .625 will create way to much pressure and said he would be very surprised if it didnt blow the seals in the caliper! This is also affected by the pedal ratio. I have made the powerstop rotor and pad change but have not been able to bed in my brakes yet. I also was leaning toward making this change next time the body is off but what the guy at willwood said scares me. He seemed pretty sure of himself. Does anyone know the pedal ratio for what we have?

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    Member stang_killer's Avatar
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    ok, going to hold with the current masters for my cobra setup front and rear. If I am not happy with stopping will try different pads.

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    Director of R&D, FFR Jim Schenck's Avatar
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    Brett,

    The 5/8 master without power assist won't make so much pressure that it causes problems. The pedal ratio in the willwood box is 6:1 and the pressure it takes to lock the rears would be the same no matter the master size, they would lock long before the seals would blow out. We have used a 5/8 on both street and track cars with no issues.
    Jim Schenck
    Factory Five Racing

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    Senior Member ehansen007's Avatar
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    So we pretty much need a brake setup for a 1 ton mustang. Make it happen Jim.

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    Senior Member 1fastsedan's Avatar
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    Quote Originally Posted by Jim Schenck View Post
    Brett,

    The 5/8 master without power assist won't make so much pressure that it causes problems. The pedal ratio in the willwood box is 6:1 and the pressure it takes to lock the rears would be the same no matter the master size, they would lock long before the seals would blow out. We have used a 5/8 on both street and track cars with no issues.
    I thought the hot rod used the 5.1:1 ratio pedal box from Wilwood?

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    Thank you for all your responses, I'm going to go with changing the brake pads first. It's winter here I'll let you know how it works out when the weather breaks.

  18. #18
    Director of R&D, FFR Jim Schenck's Avatar
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    Wilwood makes a 5:1 assembly but the one we give is the one they list as 6.25:1
    Jim Schenck
    Factory Five Racing

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    Senior Member ehansen007's Avatar
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    Quote Originally Posted by TerryP View Post
    Thank you for all your responses, I'm going to go with changing the brake pads first. It's winter here I'll let you know how it works out when the weather breaks.
    I tried that as well. I first bought the Hawks on Jim's recommendation. They were second choice to the Carbotecs that are much more expensive. And they did nothing for me. The Brakemotiv rotor pad combo worked the best. I think it's a combination of a lighter metal (maybe even cheaper China steel) with the cross drilling lightens it more and the pads they give you that make it stop better. For $150 for pads and rotors it's hard to beat. But if you go with the Carbotecs, I'd be interested to know how they work for you. I just noticed that Cabotec actually has Factory Five listed as a reference for pads. Is this your work Jim?

    http://www.ctbrakes.com/pads.asp?Make=Factory-Five

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    Hi ehansen007

    Thank you for all of your postings. First of all are we talking about the 33 hot rod kit? I think you are? The problem with the brakes basically is the compound of the pads. We have to understand as 33 builders that this car has no power assist. A brake pad that is a soft compound for grip and a rotor with a rough surface is going to give us our best stopping power. Keep in mind a vented rotor does nothing for the stopping power. It's only to cool the brakes and in the same sense holes drilled in rotors and slotted rotors let you stop better in the rain. And I don't know why we should have to spend all this money to correct a brake problem when we bought the kit with brakes included that is suppose to stop the car?

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    Dreamer j33ptj's Avatar
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    Can a power assist be installed (electric perhaps??)?

    Would that solve the problem, but is there enough room in the engine bay to install it???

    Robert

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    Yes it can, I have the design for my system frozen and will offer it as a kit when complete. The down side is the expense.

    I spoke with one builder recently that installed a vacuum system as well. This would be a less costly system to install.

    It's interesting to read this thread. You can go over to the Cobra side of the "other forum" and find page after page of the identical comments, responses and solutions to the manual brake concerns. There are a number of threads that compare the two. Not one comment that a person changed from manual and was disappointed. Many that state they wish they had done it sooner. With over 8,000 FFR Cobra kits out there, a large number now have power brakes. With me, it's not a debate, I have experienced both and know what system I prefer.

    It can be done at a reasonable cost as well. The benefits and piece of mind can't be questioned from a safety stand point.

    My first cobra had manual brakes and i had a similar experience to that outlined above. Almost rear ended a car behind a semi truck. Every car built after that had power brakes and I strongly recommend it to customers as well.

  23. #23
    Senior Member ehansen007's Avatar
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    Quote Originally Posted by TerryP View Post
    Hi ehansen007

    Thank you for all of your postings. First of all are we talking about the 33 hot rod kit? I think you are? The problem with the brakes basically is the compound of the pads. We have to understand as 33 builders that this car has no power assist. A brake pad that is a soft compound for grip and a rotor with a rough surface is going to give us our best stopping power. Keep in mind a vented rotor does nothing for the stopping power. It's only to cool the brakes and in the same sense holes drilled in rotors and slotted rotors let you stop better in the rain. And I don't know why we should have to spend all this money to correct a brake problem when we bought the kit with brakes included that is suppose to stop the car?
    The 33 always! I am definitely no expert on the subject and sometimes things just work better. And there are so many different opinions out there. I tried going the route you're about to and it didn't work for me. Upgrading to Hawk pads on stock rotors was slightly better by about 10%. Then the Brakemotive (ebay) rotor pad kit gave me another 10% on top of that and the rotors look better and won't rust. I'm sure there's a reason and I surmise that it could also be that the the cross drilled are a bit lighter and maybe even the composition of the steel is different and performs better with the pads it comes with (I tried the Hawks on the cross drilled and they were worse). So, basically, we've had a few guys on the FFCARs forum (including Dan Ruth, who's done his share of racing and race car prep) try these Brakemotiv setups out and they just worked. So, I won't be getting out my clipboard and my lab coat when they just work for that price! I've done my share of testing!

    For the record, you won't find a race car with drilled rotors. Some are slotted but but that's about it. I agree with the principles of high heat on racing brakes. Mine's more of a street car.

    As far as what comes with the kit, they are designed to be swapped from a mustang which is a car with power brakes. However, our car is extremely light and it shouldn't matter that we don't have power brakes but they don't work very well for sure. But you're right, they should stop the car out of the box. With that said, there is much room for improvement in MC sizing and pad rotor combos. Personally I think they should just supply the brakemotive-like setup or better pads and maybe change the MC. But that's their decision.

    For reference here's a little piece I found a while back on the subject with some real testing and results. I hope you find them useful as I do.

    "There are many claims as to the benefits of drilled vs slotted rotors on stopping power. This guide is intended to provide some facts about drilled and slotted rotors. As a member of the SAE (Society of Automotive Engineers), I was pleased to see a paper "The Effect of Rotor Crossdrilling on Brake Performance" by two GM engineers published in 2006. They examined three vehicle platforms with cross-drilled rotors vs standard rotors to measure convection cooling capability, fade characteristics, wet braking, pedal feel and lining wear. The result is summarized as follows:

    For the sports sedan, the coefficient of friction was 21% higher for drilled rotors than standard front rotors at 340F and higher using 15 brake snubs at 62mph. The track simulated 124 mph fade test showed 37% better brake output for drilled rotors. The drilled rotor brake temperature was about 150 degrees cooler.
    For the performance car, the coefficient of friction was significantly higher for drilled rotors especially at high temperature.
    Wet braking at high pedal pressure was the same for drilled or standard rotors. Wet braking is not significantly improved by drilled rotors.
    Pedal force was much more consistent with drilled rotors over the brake temperature range. That is, to stop at the same deceleration rate, the driver does not need to modulate pedal pressure based on different brake temperatures. This reduces driver fatigue and improves brake response.

    The authors also reported that drilled rotors prevent pad resin glazing on the rotor. So we now have solid evidence that drilled rotors have benefits over standard rotors. However, I have not found any published paper to show how slots affect brake output. So I reviewed inertial dynamometer tests using ISO NWI 26867 from Link Testing in Detroit with slotted rotors vs standard rotors. The results showed no significant difference in the coefficient of friction during the fade sections, hot stop section or pedal sensitivity portion of the test. My hypothesis is that slotted rotors do not contribute to rotor cooling whereas drilled rotors improve convection heat transfer to cool rotors and reduce brake fade. I should also point out that the pad lining wear for the slotted rotor was very severe during the test, i.e. the pad was chewed up over 20% more than the lining with stock rotors. While I believe that slots will help remove gas and debri from under the pad, I am not sure that this has a significant effect on brake torque for normal street driving. Perhaps the effect of slotted rotors is more significant on the race track, and conversely, I believe that drilled rotors are better for street and highway driving. For most drivers, I recommend drilled rotors over slotted rotors, and this conclusion is supported by the fact that Corvette, Ford GT, Porsche, Mercedes and BMW come with OEM drilled rotors"
    Last edited by ehansen007; 03-03-2012 at 02:08 PM.

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    Tim,

    Three 33s were built in my area and all have brake problems. Soft pads with the GT front brake setup improved braking but did not bring the stopping power up to an acceptable level. I would like to see more information on the electric brake booster. With my under construction 33, a vacuum unit is not an option due to the fact that it will not work as designed due to my camshaft. I have only 11 - 13 inches of vacuum with the cam grind. One available option is a caliper and disk upgrade. Do you know of anyone who has personal experience with the optional 6 piston Wilwood Calipers and the larger disks? Any help will be greatly appreciated.

    Ken Frederick

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    The rotors are cad coated so they will remain looking excellent and the shields provides you with extra chew. also transfer it to bed the shields effectively so that some pad content gets moved to the blades for extra hold.

    Dulles Airport Limo Services | Dulles Airport Limousine | Dulles Airport Limousine Service | Dulles Limo | Dulles Limousine
    Last edited by Schmities; 11-13-2015 at 08:08 AM.

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    Senior Member Jay Mann's Avatar
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    Quote Originally Posted by Ken Frederick View Post
    Tim,

    Three 33s were built in my area and all have brake problems. Soft pads with the GT front brake setup improved braking but did not bring the stopping power up to an acceptable level. I would like to see more information on the electric brake booster. With my under construction 33, a vacuum unit is not an option due to the fact that it will not work as designed due to my camshaft. I have only 11 - 13 inches of vacuum with the cam grind. One available option is a caliper and disk upgrade. Do you know of anyone who has personal experience with the optional 6 piston Wilwood Calipers and the larger disks? Any help will be greatly appreciated.

    Ken Frederick
    I installed the complete Wilwood front and rear optional brakes. Using a .75 m/c front and .625 on the rear. I bedded the brakes by repeatedly stopping hard from 60 mph until they faded (smoked) then drove for an hour to cool, as per Wilwood instructions. I have no problem locking up all four corners if I push on the pedal. I installed the Wilwood biaas adjuster to get the balance right. I had the car on an open highway in a rainstorm on the weekend. It stopped straight and true from 60 mph with the tires in the water. Excellent moduation and feel.
    www.33coyote.com
    Built with the help of my dad and sons
    coyote/TKO 600, Wilwood Brakes,Boyds tank, QA1 shocks
    Speedhut Gages, rag top, bike fenders, power steering

    "Never let physics or common sense get in the way of a good idea"

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    I have just ordered my hot rod kit and I bought a used 98 mustang corbra differential with the 11.65" brakes. The kit comes with 11" brakes in the front, is that going to be a problem?

    Muggs

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    Are you running an AOD trans?
    If so, you may have your tv cable mis-adjusted causing the trans to stay locked up and pushing you even at idle

  29. #29
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    Quote Originally Posted by Muggstang View Post
    I have just ordered my hot rod kit and I bought a used 98 mustang corbra differential with the 11.65" brakes. The kit comes with 11" brakes in the front, is that going to be a problem?Muggs
    The kit NOW comes with the 3/4" MC for the front and the 5/8" MC for the rear. I think with your combo that should be fine size wise based on what Jim Schenck
    told me at SEMA the last two years. He had me change my rear MC because on the earlier kits like mine they had the 3/4 on both and it didn't balance out right.

    He is a big believer in the new Hawk pads but I opted for a pad from EBC that has way better cold bite. I won't be racing mine so they will always be running cold
    and likely never build the heat needed to make other pads work well. YRMV
    Dale

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