new rotors feel warped when hot

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Old Mar 22, 2009 | 02:12 PM
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new rotors feel warped when hot

I just installed my OCAutosports rotors and Project U B-Force pads.

During the break-in procedure, when the rotors got hot, I felt the brake system "pulsating" (like it does when a rotor is warped). It was faint, but definitely there.

Then I took the car for a drive. When the rotors are cool, there is no 'pulse' in the brake system. But, once those rotors got hot, the brake pulse got really bad. Embarrassingly bad. My dashboard was shaking violently when I slowed from 60 to stop. Obviously, something isnt right.

Anyone have any ideas? These are the cross-drilled / slotted rotors from OCAutosports. A few other members have these - any of you guys have this experience? Is this normal behavior for cross-drilled / slotted rotors?

Its Sunday - so I'll call the OCAutosports guys tomorrow. Any feedback from G35Driver knowledge base is appreciated.
 
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Old Mar 22, 2009 | 04:59 PM
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Follow instructions in FSM to measure the oem specification for hubs and rotors............the maximum run out is 0.0028".
 
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Old Mar 22, 2009 | 05:16 PM
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There's one reason why I won't ever go cheap on rotors... even those cheap Kragen's blanks are better quality than a lot of cheap quality aftermarket rotors... I could be wrong and you've found a way to accumulate carbon build-up on your new rotors already somehow...

BTW, unless you've upped the size of your rotors, those slotted and cross drilled rotors aren't helping you stop faster... in fact, since you've lost contact surface with the drilling and slotting, your braking abity has now diminished a bit. But those rotors will stay cool!
 
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Old Mar 22, 2009 | 07:37 PM
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I bought these for looks. I dont track / race my car.

I did assume these rotors would perform like stock or slightly better. These are people on this forum that have bought these have reported good things.

Ill check them for warp... though I doubt these are warped, they are new.


What strikes me as odd is that the 'pulse' doesnt happen until they are hot. If they were warped, it would happen all the timw.
 
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Old Mar 22, 2009 | 10:17 PM
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I have them, no rattling, just broke mine in the other day, however I do have issues with squeaking, it might be the stillen pads.
 
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Old Mar 23, 2009 | 01:27 AM
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Originally Posted by stephenw
What strikes me as odd is that the 'pulse' doesnt happen until they are hot. If they were warped, it would happen all the timw.
Well, I have no experience with that shop or their parts, so I can't say if they're good or not. But it sounds like it could be a defective rotor if you just installed them (which really isn't a big deal, you just don't want a defective part on your car). I'd give them a call about it rather than asking the forums because all the answers on here can't help fix this issue...
 
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Old Mar 23, 2009 | 12:04 PM
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How does it feel when the rotors are hot but you aren't doing a hard stop? What does the brake pedal feel like? You might want to check to see if the rotor is clearing the hub bore on the hub assembly.
 
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Old Mar 24, 2009 | 08:41 AM
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Originally Posted by stephenw
II did assume these rotors would perform like stock or slightly better. These are people on this forum that have bought these have reported good things.

That really all depends on the quality of metal used. A lot of aftermarker rotor companies use cheaper steels to increase their margins. Cheaper steels react differently under heat and stress. One reason why i wish they included material cert paperwork with rotors when you buy them.
 
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Old Mar 24, 2009 | 01:36 PM
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Update...

I swapped the front right rotor out w/ the oem rotor, and went for a ride. My brakes were smooth, no pulse at all.

I called OCAutosports and spoke w/ them about this issue. They are covering the rotor under warranty, so I'll have a new rotor asap. They are also paying to have the old rotor shipped back to them for inspection.
 
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Old Mar 24, 2009 | 05:05 PM
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StephenP,

I just want to make sure that my guys are on top of this and that you guys have the utmost priority. Can you PM me your name, address, phone number and order number? Thanks.

David
 
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Old Mar 24, 2009 | 05:20 PM
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^^

I just ordered mine today and will have them installed by this weekend =) will keep you posted
 
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Old Mar 24, 2009 | 08:39 PM
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Originally Posted by OC Autosports
Can you PM me your name, address, phone number and order number?
David
pm sent
 
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Old Mar 25, 2009 | 05:02 AM
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Originally Posted by OC Autosports
StephenP,

I just want to make sure that my guys are on top of this and that you guys have the utmost priority. Can you PM me your name, address, phone number and order number? Thanks.

David
I should be receiving my set Thursday. I hope this doesnt happen.
 
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Old Mar 26, 2009 | 11:33 AM
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Originally Posted by UrangeAve
I should be receiving my set Thursday. I hope this doesnt happen.
I've sold many sets to members on here and they can vouch for me that it has not been an issue for them. We do however cover you in the rare event that this does happen. In fact, this is the first.

StephenP, we are in the process of sending you a replacement. I have your invoice on file and will keep you in touch. Thank you.

David
 
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Old Mar 26, 2009 | 11:36 AM
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nice customer service ..
good to see it still exists ...
 
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