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      01-20-2008, 11:50 AM   #1
Bastet
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Help please - Brake discs - is this normal ?

Could someone tell me if it's normal that one of the break discs is grooved (1st photo) ? All the others are really smooth (like in the second photo) but one has grooves. Should I be worried/take the car back to the dealer/just forget about it and enjoy driving ???
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      01-20-2008, 12:06 PM   #2
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Scored brake rotor

No, it's not normal, but not unusual. Probably got some debris caught between the rotor and disc. It shouldn't have much effect on braking, but I''d show it to the dealer. They may well go away on their own in a few thousand miles.

On GM cars rotor grooves of up to .060 inch are acceptable if the rotor meets all other specifications. Not sure what BMW specs say.
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Last edited by GregW / Oregon; 01-20-2008 at 12:28 PM.
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      01-20-2008, 12:07 PM   #3
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I do see the grooves in the first pic. I would say if no other brake discs have this scoring, you might want to take it in.
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      01-20-2008, 12:10 PM   #4
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Thanks guys ! I knew it - I hate returning to the dealers for something like this !
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      01-20-2008, 12:23 PM   #5
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Those brakes are not even broken in yet as the machining marks are still on the surface.Read this link about brake & rotor "bed in".I have been using the methods used here with very few braking problems in both street & race cars.

http://www.stoptech.com/tech_info/wp...contents.shtml
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      01-20-2008, 12:26 PM   #6
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Read this link about brake & rotor "bed in".
thanks !
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      01-20-2008, 05:55 PM   #7
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not normal. i would only be concerned if youre having vibrations or squeaking. if its not bothering you in any way, dont take it in, because you can be sure the dealer is gonna pile on the bullshit and youre gonna be spending $$$.
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      01-20-2008, 06:02 PM   #8
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not normal. i would only be concerned if youre having vibrations or squeaking. if its not bothering you in any way, dont take it in, because you can be sure the dealer is gonna pile on the bullshit and youre gonna be spending $$$.
I would not follow this advice.
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      01-20-2008, 06:04 PM   #9
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i don't think there is much downside here. it can make noise. it's not as if the groove is so deep that the rotor will crack. the dealer will want and love to replace the pads and the rotor, and that will cost dearly. if it starts vibrating, that would be problematic because that can affect performance, at which point i'd take it in, so i agree with the sexy member. or i guess the alternative would be to take it in and ask them to remove whatever is stuck on the pad, but they most likely won't want to do that saying they need to replace everything. if there is nothing stuck on the pad, one could argue the pad was defective.
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      01-20-2008, 07:37 PM   #10
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If there is something stuck between the pad and rotor, you would most likely hear it at all times. That space is fairly small. Also, it looks like you have three marks. Would be hard for three different pieces of debris to be there. Looks most likely your pad is the culprit.
If you don't hear it at all times, it seems like a problem with the pad scoring the rotor. Which the dealer would have to replace.
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      01-20-2008, 08:14 PM   #11
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i don't think there is much downside here. it can make noise. it's not as if the groove is so deep that the rotor will crack. the dealer will want and love to replace the pads and the rotor, and that will cost dearly. if it starts vibrating, that would be problematic because that can affect performance, at which point i'd take it in, so i agree with the sexy member. or i guess the alternative would be to take it in and ask them to remove whatever is stuck on the pad, but they most likely won't want to do that saying they need to replace everything. if there is nothing stuck on the pad, one could argue the pad was defective.
Wouldn't replacement be covered under warranty?
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      01-20-2008, 08:17 PM   #12
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Wouldn't replacement be covered under warranty?
If they attribute it something getting caught in the pad, they would probably argue that is not warranty related. If they attribute it to the pad itself, then they would have to cover it given it's a brand new car. In the US, it wouldn't be an issue as we have the 4 year warranty+free service deal, so it wouldn't matter what has caused it.
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      01-20-2008, 10:39 PM   #13
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Quote:
Originally Posted by Stahlgrau View Post
Wouldn't replacement be covered under warranty?
That would most likely be covered under free maintenance in the US, but they don't get this in Europe, despite paying more.
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      01-20-2008, 11:37 PM   #14
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+1 on those brakes not being broken in.
You can still see the diamond criss cross marks from original manufacturing.
Go bed them in on a freeway early morning and see what happens.
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      01-20-2008, 11:45 PM   #15
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Break in of brakes

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Originally Posted by OzStriker View Post
+1 on those brakes not being broken in.
You can still see the diamond criss cross marks from original manufacturing.
Go bed them in on a freeway early morning and see what happens.
Good advice.
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      01-21-2008, 05:37 AM   #16
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Our warranty covers pretty much everything during the first year, so I'll probably go show the discs to the dealership anyway, just to be on the safe side...
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      01-21-2008, 09:26 AM   #17
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Rotor scoring

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Originally Posted by Bastet View Post
Our warranty covers pretty much everything during the first year, so I'll probably go show the discs to the dealership anyway, just to be on the safe side...
I doubt this is technically a warranty issue (defective parts), but likely will be considered a wear issue. Good luck with the dealer. If they don't think it's important, just drive it and the rotor may even out.
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      01-21-2008, 10:00 AM   #18
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I would not worry about it,because one of the problems with drilled discs is that the scoring of the disc face is pretty normal.I am not a fan of drilled discs as when used on track they tend to have cracks that start ot the holes,whether they are cast or machined after.On Porsches they are cast and they also do crack after a few hard days.A lot of the scoring on your discs might have been caused by rust particles coming out the holes and getting collected on the pads.On a lot of street Porsches I have noticed brake pad material actually filling up these holes.I prefer Slotted discs,much more servicable for hard use.
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      01-21-2008, 10:41 AM   #19
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I don't think that those disks are broken. Long-term if you have breaks instead of brakes you'll be in the shop a lot.

Dew yew sea what eye did their?
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      01-21-2008, 11:37 AM   #20
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Quote:
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I don't think that those disks are broken. Long-term if you have breaks instead of brakes you'll be in the shop a lot.

Dew yew sea what eye did their?
Nice attitude, n00b.


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      01-21-2008, 12:54 PM   #21
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Nice attitude, n00b.


Best regards, south
Laugh a little there chief. Relax.

Minus whale because for all intensive porpoises life is two short.

Ultimate regards,

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      01-29-2008, 02:50 PM   #22
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Just thought I'd let all those who read this know that after a few days of working the brakes pretty hard the grooves are virtually gone. I'm quite surprised that they have reduced so much as i could easily feel them on the surface.

Makes me wonder how the discs and pads will wear the miles??? Only time will tell, but hopefully they'll last a good while.
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