Brakes Need Help Identifying My Cobra Brakes..

35thGTLimited

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Mar 10, 2007
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The Pocono's
EDIT: Short version: It's such a wall of text, basically I'm trying to identify what year my brakes may be, my car is a 2000GT, and I guess just knowing if the 99-01 Cobra brakes were the same, that'd be enough. But my main reason for asking.. When I come to a stop, right at about 3-4 MPH, the brake pedal very gently vibrates a bit and gets slightly stiffer, then as the car comes to a complete stop, the pedal feel goes directly back to normal. This isn't intermittent, it's always, since I bought it, about 2,500 miles, no other issues, they perform very good in fact.


I bought this car about two months ago, mostly just because I spotted it at an incredible price, and I don't need to daily drive it. Normally I wouldn't go anywhere near such a heavily modified car, but what can I say, I haven't had a 'fun' car in nearly ten years, and when I test drove it, it just infected me.

So, I'm not expert, and I've only ever owned GT Mustangs, except for a Fox body LX I had way back.

So my question, this car (2000 GT Convertible) has Cobra brakes, but I have no idea what year they're from. They are definitely not the Cobra R brakes, and so I'm assuming 99 - 01 Cobra, and I just don't know if there's any difference. All I have is a picture, if it's not good enough I can take a few more pics later today. If there's anything else I can do to help identify, please let me know. Also I fully understand how... complicated I may have made things for myself by buying such a modded car without even being a novice mechanic. Basically, nothing is stock except below the heads, everything has been done. I'm still figuring things out as I go along. Sorry for rambling, here's the pics I have.
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Well I guess if there are any experts that happen to see this post, my issue is the following. When I come to a stop, right at about 3-4 MPH, the brake pedal very gently vibrates a bit and gets slightly stiffer, then as the car comes to a complete stop, the pedal feel goes directly back to normal. I have no idea if it could be the calipers, but I figured this behavior must be related to the ABS. Which leaves me in a difficult place, again, being a novice, and also not knowing what to tell the shop when I take it in. Though they say they're very knowledgeable of these cars and feel they can figure it out. I'd like to save some money, fix it myself, and learn something in the process. Thanks a million for any input. I'll keep a close eye on the thread, but I'll be going to sleep soon for a bit, just now finishing up a third shift. Sorry again for the wall of text, I'm over tired, very, very tired, I guess this is the effect it has on me. Thanks!
 
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Sounds like your ABS, if the car is equipped, is activating for some reason as you stop.

Are your tire sizes way off? Any ABS light?

I had the same cobra brakes on my 2003 GT. No problems, car stopped awesome and brakes felt great. I'd say your issue is unrelated to the actual type of brake on the car, and more a mechanical issue with either the ABS system, or perhaps the pads have worn down and you have some metal on metal contact, which would require pulling each caliper off and looking.
 
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Yeah the wheels and tires are way over sized, just had an inspection so I'm pretty sure the brakes are good, but maybe I should double check just in case they glossed over it. The wheels are 20", and really wide, not sure if that can contribute to the problem. 245/30/ZR20 in front and 295/30/ZR20 in back. Not sure what I'd do if the size affects it, I really like the wheels and suspension, it makes the car feel very modern and drives very nicely. Sadly I don't have a set of stock wheels to throw on it and test if there's a difference, I'll look around just to see if I can score a good deal. Oh also, no ABS light, though like a month ago when I was cruising on the highway, it came on for like 2 minutes then went off, haven't seen it since then, about a thousand miles since then.

It doesn't affect performance at all, just weird, and strangely consistent, the harder I am on the brake, the more noticeable it is, if I super gently roll to a stop easy on the brake, doesn't do it at all. I think I have a shop nearby who does a lot of aftermarket work on cars, especially Stangs, I'll take it to them. Thanks for the input.
 
Yup, it's your tire sizes. There is too much of a difference in diameter. Your fronts are 25.8" in diameter, and your rears are 27".

The abs system can only handle a small difference between front and rear tire diameter. 3% or less. You are almost 5% difference, so the abs is getting confused and activating.

The fix is to adjust your tire diameters to be closer to each other


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Let me double check. Okay, I had it written down wrong for some reason.. Let me try this again, sorry I get lost a bit, too many cars atm, I struggle to keep track.

Fronts are 245/35/ZR20
Rears are 285/30/ZR20

No idea if that is any better, or worse? Edit, just used a calulator (for R tires, not ZR, but I'm pretty sure that won't matter here) and it's 0.4% off. Should be okay?
 
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Isn't their a different sensor or way to reprogramming for larger tires. You could always find someone that could change out rotors/ calipers to non abs, depends on how much you want to keep tire/wheel combo. It's probably cheaper and easier to get rid of wheel combo .if it were me I'd run an abs scanner tool into your port, to be sure. It might be a simple fix. Their might be a way to reprogram for larger wheels. You can't be the first one to do this. Could be a abs module or computer acting up.


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Isn't their a different sensor or way to reprogramming for larger tires. You could always find someone that could change out rotors/ calipers to non abs, depends on how much you want to keep tire/wheel combo. It's probably cheaper and easier to get rid of wheel combo .if it were me I'd run an abs scanner tool into your port, to be sure. It might be a simple fix. Their might be a way to reprogram for larger wheels. You can't be the first one to do this. Could be a abs module or computer acting up.


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Yeah, going into the shop either this coming Tuesday, or the following. I definitely want ABS, and no way I'll give up the wheels, they cost a fortune, hoping it's just something minor.
 
Fronts are 245/35/ZR20
Rears are 285/30/ZR20

Those sizes are better. 26.8" front and 26.7" rear. Well within what the abs system can handle. So I don't think tires/wheels are the issue. Swapping wheels temporarily would be a help in eliminating that cause.


Still sounds as is the abs still is activating. Could be a bad sensor or some debris screwing with the sensor. Hard to diagnosis over the net though.


You could always pull the abs fuse. The ligh on dash will come on and your abs/traction control is now disabled. Now try to duplicate the problem. If it's gone, it's the abs system. If still there, it has nothing to do with abs



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Okay, yup, it's def something with the ABS, just did that, it's rainy and slick as hell, was not hard to verify lol. It will go into the shop hopefully this week, if not next Tuesday. I have my Taurus if I must let it sit. Thank you very, very much for your insight, it's appreciated quite a bit. Very nice people around here willing to take time to help others. Nice to see. All of the Tech and Gaming forums I go to, it happens, but it's always messy.
 
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