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Warped Rotors At 2300 miles. Replace or resurface?

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CarcaineProblem

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To every one recommending hard stops, I did that a bunch of times to no avail. I didn't go to the dealer until the problem seemed to be permanent. The shuddering is intense regardless of speed or what I do. I de rusted the rotors by braking from 100-120mph a bunch of times. I kept driving with it for almost 500 miles hoping it would go away, but nope, it is still there. Even the dealer is shocked. They wanted to write it off as "flat spots in the tires causing the vibration", but there were no visible flat spots.

My only concern is what should the next step be: resurface/turn, or replace? The dealer is not budging on a replacement. They are insisting I just turn them but I dont feel good about it, especially with that service bulletin flying around. I realize it may be because the 15-17's were drilled, but I'm not sure if that's the case.
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Hack

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To every one recommending hard stops, I did that a bunch of times to no avail. I didn't go to the dealer until the problem seemed to be permanent. The shuddering is intense regardless of speed or what I do. I de rusted the rotors by braking from 100-120mph a bunch of times. I kept driving with it for almost 500 miles hoping it would go away, but nope, it is still there. Even the dealer is shocked. They wanted to write it off as "flat spots in the tires causing the vibration", but there were no visible flat spots.

My only concern is what should the next step be: resurface/turn, or replace? The dealer is not budging on a replacement. They are insisting I just turn them but I dont feel good about it, especially with that service bulletin flying around. I realize it may be because the 15-17's were drilled, but I'm not sure if that's the case.
Frankly I doubt resurfacing will cause a problem on a non-drilled rotor that wouldn't be obvious immediately after the work is done.

Meaning - the unique thing about the rotors are the pins that allow the rotor to expand on the hat. If you turn the rotors and that operation damaged the pins I think it would be immediately obvious. And it doesn't seem likely to happen in my opinion. Braking loads (and shock) are extremely high and I don't think that resurfacing will apply heavier loads or shock to the rotors. Machines for resurfacing brakes do not have 500 HP Voodoo engines powering them!

If this doesn't convince you, I think liability would prevent the dealer from doing something shady to your braking system. You could try to get something in writing to alleviate your concerns and so that you have recourse if one or more of the rotors fail at a later time.

Last option - go to another dealer and see what they will do for you.
 

stanglife

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To every one recommending hard stops, I did that a bunch of times to no avail. I didn't go to the dealer until the problem seemed to be permanent. The shuddering is intense regardless of speed or what I do. I de rusted the rotors by braking from 100-120mph a bunch of times. I kept driving with it for almost 500 miles hoping it would go away, but nope, it is still there. Even the dealer is shocked. They wanted to write it off as "flat spots in the tires causing the vibration", but there were no visible flat spots.

My only concern is what should the next step be: resurface/turn, or replace? The dealer is not budging on a replacement. They are insisting I just turn them but I dont feel good about it, especially with that service bulletin flying around. I realize it may be because the 15-17's were drilled, but I'm not sure if that's the case.
Have they even pulled the rotors off yet or are they guessing? If there's something stuck to the rotor, could be on the backside where you cant see it, is why I'm asking.
 

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plus you can't surface a rotor while it's on a loose hat. It has to be mounted solid to the lathe spindle. Slap the rotor onto a surface plate and put a dial indicator on it. If you also haven't ruled out a dragging caliper you're just going to destroy your new/resurfaced rotor in record time.
 

jmn444

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plus you can't surface a rotor while it's on a loose hat. It has to be mounted solid to the lathe spindle. Slap the rotor onto a surface plate and put a dial indicator on it. If you also haven't ruled out a dragging caliper you're just going to destroy your new/resurfaced rotor in record time.
loose hat?
 

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stanglife

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shogun32

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loose hat?
the rotor disk floats on the hat. the 2 pieces needs to be rigid if you're going to surface it. Otherwise you have disassemble and make a custom hub.

a partial hub indexed off the rotor mount surface with say 5-6 pins and then clamped could work but I don't know how flat or concentric the mount surface really is.
 

shogun32

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Hack

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wait what?
https://media.ford.com/content/ford...lby-gt350-suspension--chassis-and-brakin.html

' Two-piece brake rotors for Shelby GT350 and Shelby GT350R are the most powerful brakes ever fitted to a production Mustan '

' The two-piece rotors are assembled with an offset floating-pin system that allows for improved cooling and ventilation. '
Yes it's "floating", but it also isn't "loose". If you picture the pins pointing radially outward from a center point, once you have more than 1 pin the rotor and hub cannot move with respect to each other. The pins allow for thermal expansion movement, but that's it. There is no movement at all between the hat and rotor.
 
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Caballus

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If they are actually warped this won't help. However, if it's brake pad deposit it might. I've done it a couple times to stop squealing and it works like a charm. Assuming you have the means, it may be worth a shot.

Edit: Will be a good opportunity to install Caliperfexion studs as well.
 

Alain

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you can turn those non drilled rotors with no problems.

that service bulletin for earlier models was due to those rotors being drilled, can't turn those, they must be replaced if they go bad.

Good luck fighting with that dealership. Some dealerships are like politicians these days, they'll lie to your face and no one will hold them accountable.
 

shogun32

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There is no movement at all between the hat and rotor.
when you put a side-load on it with a cutter? if the pins have to be a sliding fit the ring is going to rock when you try to turn it. I guess not enough to matter. I think in thousandths of an inch. and if the turned surface is no longer really square with respect to outside and inner edge, the pads will just cant to compensate...
 

Hack

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when you put a side-load on it with a cutter? if the pins have to be a sliding fit the ring is going to rock when you try to turn it. I guess not enough to matter. I think in thousandths of an inch. and if the turned surface is no longer really square with respect to outside and inner edge, the pads will just cant to compensate...
Seriously, there is ZERO movement. None. Yes if you put a load on anything - even a one piece rotor - it will move some amount. Of course it will. That's how the world works. Everything bends under load. But the GT350 rotors are very beefy, strong units designed for track use. They are not Camry brake rotors that can't handle much load.

But what I'm saying is if you pick up a GT350 rotor and hold the hat in one hand and the rotor in the other, you will not feel any "looseness".

The rotors aren't manufactured in a crappy, low tolerance, Chinese way. They are seriously awesome units. I've handled the rotors before and they are beautiful precision pieces.

The iron ring on the outside is allowed to expand radially outward when you get the brakes hot, though. You hear a multitude of clicking sounds from the rotors when the car is sitting after a track session. My interpretation of the reason for that, is that the pins are a tight fit, but the pressure from the rotor expanding with temperature overcomes that tight fit and the rotor is allowed to move when it gets hot.

These rotors work as advertised. They are a major reason why the GT350 is such an amazing car.
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