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      05-25-2011, 07:37 PM   #23
elh0102
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Quote:
Originally Posted by KGB7 View Post
Thats called brake fade. The pad can have full contact with the rotor, but the pad will no longer have "grip" or "resistance" against a rotor. Thus the car doesnt stop.


http://en.wikipedia.org/wiki/Brake_fade





http://en.wikipedia.org/wiki/Disc_brake

Scroll down to;
Disc damage modes
But you asked, "how exactly would a pad deposit stick on to a moving rotor???" You said I did not answer that, so I tried again. Of course fade would result, but if you overheat pads, you will also get uneven compound transfer to the surface of the rotor.
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      05-25-2011, 07:48 PM   #24
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Quote:
Originally Posted by elh0102 View Post
But you asked, "how exactly would a pad deposit stick on to a moving rotor???" You said I did not answer that, so I tried again. Of course fade would result, but if you overheat pads, you will also get uneven compound transfer to the surface of the rotor.
I understand now what you are saying, i was looking for a different explanation.


Not always true.( the bold sentence).

If you have one large brake pad and a one piston caliper, then 1/4 the pad will do what you said will do. Dont forget, there is a steel plate that is forcing all that brake pad mush on to a rotor. That steel plate would also have to be warped. I have yet to see one that was warped.

If you have same pad with 6 piston caliper then most if not all of the pad will have full contact with the rotor.


Either way, Many people have brake dust build up and many if not most of them dont have warped rotors after 6k miles.

I used to have Brembo rotors and pads on my Dodge Durango, i warped the rotors after one summer of driving, simply because that summer i towed cars and boats.
Once i stopped towing, i replaced pads and rotors, and havent had to change anything for over 5 years. The last year of owning the SUV, i wouldnt wash it for 3-4 months at a time, the brake build up on wheels looked like rust, yet my rotors werent warped. Why? Because i know how to use brakes with out killing them under normal driving conditions.
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Last edited by KGB7; 05-25-2011 at 10:38 PM.
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      05-25-2011, 09:42 PM   #25
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FYI: BMW has quietly changed the rotor composition from '08-'09 cars to a revised rotor.
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      05-25-2011, 11:20 PM   #26
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Add me to another 08 that recently change the rotors/pads after having them done just recently.

I had the same experience with my steering wheel shaking when hitting the brakes at the 50mph range. I knew right away it was the rotors, just from going thru that same thing with my other cars. Took it to the dealer and they said they replaced the rotors and brakes (front only I believe).

Around 5k miles later, the same issue started up again and I just had the rotors/brakes replaced on the car. Not sure if it was front only or back also (forgot to ask).

Felt it was strange that it happened so soon.
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      05-26-2011, 12:31 AM   #27
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long shot but possible that the wheels are over-torqued to cause this?
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      05-26-2011, 12:47 AM   #28
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Quote:
Originally Posted by Bubbles View Post
FYI: BMW has quietly changed the rotor composition from '08-'09 cars to a revised rotor.
Was a TSB (or SIB, in BMW lingo) issued? That's good to know, just in case.

Quote:
Originally Posted by e92zero View Post
long shot but possible that the wheels are over-torqued to cause this?
Unlikely, but definitely possible. Even factory torque is too much IMO. Highest I've seen for aluminum wheels is 80. BMW calls for 88, and the torque wrench on BMW's jack kit clicks at 92 ft/lbs; just too much IMO. I use 85 ft/lbs myself, but can't find the reason why not 80 ft/lbs max, like all other cars. I initially thought maybe lug bolts needed more torque than lug nuts, but Ferrari calls for 75 ft/lbs, and they use bolts and forged wheels too . Weird.
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      05-26-2011, 01:19 AM   #29
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Quote:
Originally Posted by e92zero View Post
long shot but possible that the wheels are over-torqued to cause this?
I torque the wheels on my 740 to 105lbs several times a year, yet after 7 years i have no symptoms as OP has described.
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      05-26-2011, 01:40 AM   #30
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i just got my rotors replaced just got the car back today. The dealer did say mine were warped but just to make sure they replaced calipers and pads while they were doing it.
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      05-26-2011, 02:30 AM   #31
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Add me to the list. Mine is a 08 e90 M3 and have had 2 sets of new front rotors. The last time, the dealership made sure they were revised part codes and changed the rears too.

(BTW, I've had a brand new 2011 engine put in and a new rear exhaust. The original 2008 engine developed a knocking at startup and the rear exhaust started rattling at around 2900rpm)

Everything under warranty. (I demanded an extra year on my warranty - which they extended) Car is awesome now....
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      05-26-2011, 06:48 AM   #32
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Did you bed the new brakes in any of the 3 sets?

I went through a set of rotors in the first 10k miles - thought it was due to a curb incident on a track that did damage to the bearing and upper control arm - but maybe not.
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      05-26-2011, 07:57 AM   #33
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Quote:
Originally Posted by rfowlerm3 View Post
I am absolutely being honest. Anyone else out there experiencing this problem?
Never heard of such a thing. I've had 5 BMW's too.
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      05-26-2011, 07:42 PM   #34
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Quote:
Originally Posted by elp_jc View Post
Was a TSB (or SIB, in BMW lingo) issued? That's good to know, just in case.

.
It won't be included in a TSB/SIB. It was a "quiet" change due to the rotor issues from early production years.
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      05-26-2011, 09:37 PM   #35
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check this out to see if you have uneven deposits

http://www.essexparts.com/learning-c.../swapping_pads
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      05-27-2011, 08:03 AM   #36
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Why doesn't one of you Guys who are convinced you have warped rotors take them to an engineering shop (off the car) for a proper examination by people who know what they are doing.

Just because the BMW Tech tell you they are warped doesn't mean they are.
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      05-27-2011, 08:38 AM   #37
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This shows that a lot of people who post on this forum don't have a clue what they are talking about.
Before making a statement make sure you have something to back it up.

http://www.stoptech.com/tech_info/wp...rakedisk.shtml
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      05-27-2011, 09:45 AM   #38
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I have had an issue with BMW shops over-torquing lug nuts with an impact gun. If you are going to the same garage, they will be repeating the error everytime you take it back. So if the new rotors are incorrectly torqued, and you repeat your habits, you will get the same result.

I always retorque my lugnuts as soon as the car is returned to the BMW specs. I have been surprised how tight that the wheels have been torqued by a shop. This is a direct result of the time allotment for jobs, for rotor and brake service, which I believe is 1.1 hrs for the tech. They are not going to be too concerned about dropping the car, loosening and retorquing the lugnuts, they will go around and check the wrench clicks and they are done regardless of the actual torque
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      05-27-2011, 11:24 AM   #39
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They aren't warped. You have pad deposits on the rotors like others have mentioned. Remove your wheels, clean the rotors and re-bed your pads properly (evenly distributes brake pad material on your rotors) and problem solved.

http://www.automotivetoolsonline.com...3_p_10014.html

http://www.automotivetoolsonline.com...11_p_9901.html
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      05-27-2011, 01:17 PM   #40
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Quote:
Originally Posted by RussRamz View Post
They aren't warped. You have pad deposits on the rotors like others have mentioned. Remove your wheels, clean the rotors and re-bed your pads properly (evenly distributes brake pad material on your rotors) and problem solved.

http://www.automotivetoolsonline.com...3_p_10014.html

http://www.automotivetoolsonline.com...11_p_9901.html
+1. This works. I will be doing this again next weekend.
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      05-31-2011, 10:10 PM   #41
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Quote:
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Question; Manual or DCT? AND... No I don't want to make this another one of "those" threads. Also, front, rear, or both sets warped?
Manual. Front only as we've tested the rears and there are no problems with the rears.
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      05-31-2011, 10:12 PM   #42
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Quote:
Originally Posted by Bubbles View Post
It won't be included in a TSB/SIB. It was a "quiet" change due to the rotor issues from early production years.
Bubbles, How do you know this? Have you seen anything in writing from BMW etc? Please let me know anything you can provide will help! Thanks!!!
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      05-31-2011, 10:13 PM   #43
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Quote:
Originally Posted by FifthStreetz View Post
I had my rotors warped after 9K miles as well. Same exact symptoms as OP, shake in steering wheel when braking above 50MPH And i dont "abuse" my car.

My buddy assumed it was also pad deposit, but when I went to dealer, they checked the rotor and the oscillation was pretty bad. My M is also a 2008

Hopefully that is the only and last time, anyone else have this issue besides OP and I?
How many miles have you done since you had them changed around 9K miles?
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      05-31-2011, 10:16 PM   #44
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Quote:
Originally Posted by warzilla View Post
Add me to another 08 that recently change the rotors/pads after having them done just recently.

I had the same experience with my steering wheel shaking when hitting the brakes at the 50mph range. I knew right away it was the rotors, just from going thru that same thing with my other cars. Took it to the dealer and they said they replaced the rotors and brakes (front only I believe).

Around 5k miles later, the same issue started up again and I just had the rotors/brakes replaced on the car. Not sure if it was front only or back also (forgot to ask).

Felt it was strange that it happened so soon.
Sounds exactly like what I went through. How many miles have you done since you had them changed a 2nd time? I'm pretty sure BMW is trying to hide the fact that the rotors on 08 M3 models are faulty.
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