|
|
|
2010 2011 BMW 5 Series Forum F10 Car Vibration when Braking |
|
Post Reply |
|
Thread Tools | Search this Thread |
05-09-2021, 10:08 PM | #23 | ||
Major
514
Rep 1,442
Posts
Drives: 2011 535i 6MT
Join Date: Apr 2019
Location: Chattanooga
|
Quote:
|
||
Appreciate
0
|
12-27-2021, 06:17 PM | #24 |
Private
29
Rep 71
Posts |
99%+ of vibration when breaking issues are NOT cause by "warped" rotors. They are caused by uneven brake pad transfer to the rotors. That usually happens when you sit on the brakes for some time (or engage the parking brake which will affect the rears only) when the rotors are really hot. Your pad basically melts onto the hot rotor surface. Just don't do it.
Also, look into the physics of braking. Pad compound is supposed to transfer to your rotors for effective braking. The point is that it should be transferred evenly so that you get consistent friction as the rotor rotates. Braking hard does not cause warping or some other kind of damage to the rotors (unless you exceed that max operating temps MOT but you won't do that on a street car in the US unless you do 1000s of 0-60 and 60-0s). So anybody telling you that you used your brakes too much or too hard or whatever is full of it. If that was the case, race cars would have toasted brakes after a lap. One way of fixing a so-called "warped" rotor is to slap on really aggressive pads (I mean aggressive race pads) and then use them to basically machine off the previously deposited brake compound from your rotors and you can start over again. I've done that several times. Next time someone claims that you have a "warped" rotor, ask them how they know that exactly? What measurements did they take and how are they arriving at the conclusion of "warping"? Ask them to numerically define what warping is means exactly? You'll see that they don't have a clue in general. If they say, I put it on a lathe and turned it and it is fine now so it was warped, that is almost always BS, too. What they did was to simply remove the uneven pad deposits from the surface of the rotor. Not somehow "unwarped" it. I guess it is *possible* for a rotor to be physically warped but I haven't seen one in 30 years.
__________________
88 S14 M3 (NASA GTS3 racecar) / 11 6MT 550i M Sport / 14 6MT M5 Competition / 15 X5 50i M Sport (tow vehicle)
|
Appreciate
0
|
12-28-2021, 11:13 AM | #25 |
Lieutenant
194
Rep 520
Posts |
My issues with vibration were solved with replacing the upper control arms due to ripped bushing and a flash from the dealer on the electronic steering. I have a very old post somewhere on that service.
The vibration for me has returned but this time it's the lower control arm. Confirmed ripped bushing.
__________________
BPM Tuned, Advanced Fuel Dynamics, Paddoq Valved Exhaust, Paddoq Magnetic Paddles, EDC dampers, Dinan Springs, H&R Sway. DCT all day long.
https://www.youtube.com/channel/UCFu...fWjCtOz49FDMlg |
Appreciate
0
|
12-28-2021, 04:40 PM | #26 |
First Lieutenant
112
Rep 384
Posts
Drives: 16 X3 28d/18 540d xdrive
Join Date: Jun 2017
Location: Western PA
|
After reading about the use of aggressive pads to machine a problem rotor, isn't that what's done when rotors are turned by a mechanic or dealer. And it seems that after this is done, some still complain of vibrating brake pedals In some cases, even installing new rotors does not help. Perhaps the problem is not the pads or rotors, but rather a worn suspension part.
With my X3 things were not that complicated. I had warped front rotor(s) at 15k miles that were replaced. After 65K miles the problem has yet to return. |
Appreciate
0
|
12-28-2021, 05:19 PM | #27 |
Private
29
Rep 71
Posts |
Yes, as I said, really aggressive pads can essentially machine off transferred pad compound so one can start from scratch. The point is the rotors not "warped."
And, yes, there can of course be other reasons for vibrations. What I am saying is that your garden variety warped rotor diagnosis from a dealer is usually BS and the rotors are extremely unlikely to be warped.
__________________
88 S14 M3 (NASA GTS3 racecar) / 11 6MT 550i M Sport / 14 6MT M5 Competition / 15 X5 50i M Sport (tow vehicle)
|
Appreciate
0
|
12-29-2021, 08:29 AM | #28 |
First Lieutenant
112
Rep 384
Posts
Drives: 16 X3 28d/18 540d xdrive
Join Date: Jun 2017
Location: Western PA
|
Why buy and install aggressive pads, when one can just have rotors turned? Aggressive pads (usually semi-metallic) can sometimes score rotors rather than producing the even, smooth surface of a brake lathe. Moreover, rotors must warp at times, otherwise what's the point of run-out gauges.
|
Appreciate
0
|
12-29-2021, 10:36 AM | #29 |
Major
1026
Rep 1,050
Posts |
lucid21 is correct. Anyone who wants to know more about this should read the white paper from Centric parts, which dispels the warped rotor myth and several others:
https://centricparts.com/getmedia/bd...c-8-2018_1.pdf |
Appreciate
0
|
12-30-2021, 12:05 PM | #30 | |
Private
29
Rep 71
Posts |
Quote:
High quality aggressive pads do not score rotors. Never had issues with Pagids or the more aggressive compound Wilwoods. Had major issues with Hawks. Having your rotors turned will cost you dearly unless you have lathe. Swapping pads will cost you 30 mins x 2 if you have the pads. I did that with an e90 m3 that i tracked a lot. Either that was to make the point that if scraping off uneven pad deposits fixes the issue you dont have a warped rotor. Not to say you should go by aggressive pads. |
|
Appreciate
0
|
12-30-2021, 12:39 PM | #31 | |
Private
29
Rep 71
Posts |
Quote:
|
|
Appreciate
0
|
01-01-2022, 08:57 AM | #32 |
First Lieutenant
112
Rep 384
Posts
Drives: 16 X3 28d/18 540d xdrive
Join Date: Jun 2017
Location: Western PA
|
Getting back to "the gross majority of warped rotors" , how does one know which is caused by irregular pad deposits and which is actually warped? What if these aggressive pads do not resolve the problem, does one return the set of used aggressive pads (to Centric) for a refund? This fix may be ideal for DIYers (like yourself) that just happen to own a set of "aggressive race pads", but would be doubly expensive for the majority of owners using dealers and independents for brake work.
Moreover, your estimate of time required for a DIY pad replacement does not apply to all BMW's. Assuming your M3 has Brembo-style fixed calipers (without brake wear sensors) it's possible to change pads in 30 minutes per wheel. However, doing the same on the F10's typically rusty sliding front calipers is rarely that fast and a task that few want to do twice. Despite my dissent, happy new year. |
Appreciate
0
|
01-01-2022, 09:41 AM | #33 |
Major
514
Rep 1,442
Posts
Drives: 2011 535i 6MT
Join Date: Apr 2019
Location: Chattanooga
|
Sounds all like semantics to me! At the end of the day if the rotor is the root cause choose your own method to fix it for crying out loud lol.
|
Appreciate
0
|
01-01-2022, 04:18 PM | #34 |
Private
29
Rep 71
Posts |
I can change pads on an axle in 30 mins with stock brakes. Does require some practice. Turning rotors is way more labor intensive btw. You have to undo large nuts and get the caliper carriers off in addition and then also actually machine them. This all is irrelevant though because, yet again, I offerred the aggressive pad approach as a means for me to verify what I had. Again I am not suggesting that you buy pads or do anything at all yourself. Not sure how many times I need to say that. I am suggesting not to stand on your brakes when they are hot.
Interesting the stoptech whitepaper says the pad approach only works with not too severe cases of uneven deposits. They have more experince so I defer to them. In terms of proof I refer you to the Stoptech guy who has examined 100s of rotors over 30 years or whatever. Ill sayvthid again: no daily driver is using brakes anywhere close tobtheir mechanical or thermal limits to warp them regrardless of how spirited of a daily driver they may be. I certainly didn't know how until I got specific training on how exactly to do that when I got first got on the track. And that is the first thing I teach beginners on thevtrack. Even if you knew how, you couldnt do it unless you speed and stop like a maniac down the Rockies on public roads or I guess you do multiple emergency stops in Germany from 200+ kph. In general, you may warm up your brakes but you wont get them anywhere their limits with the exception of fluid issues but that is a different topic and not about rotors. I sure dont when I drive around and I am glad I dont. I have, on at least two occasions, applied the parking brake after rushing to work and stopping at the bottom of a downhill off ramp and thus warming up the brakes right before parking. What do you know, I had vibrations after each occasion. I could even see the pad imprints on the rotors when I looked carefully thevsecond time. Just like the stoptech paper notes...I am extra careful with that now. What I have also observed a dozen times is beginners standing on their brakes after a track session or when there is trouble on thevtrack and stopping and then reporting vibrations in the next session. I can assure they did not know enough to bring their brakes to any kind of thermal limit. Happy new year to you as well. Last edited by lucid21; 01-01-2022 at 06:00 PM.. |
Appreciate
0
|
01-04-2022, 12:17 PM | #35 | |
New Member
0
Rep 5
Posts |
Have same problem
Quote:
|
|
Appreciate
0
|
04-09-2022, 03:24 PM | #37 |
Enlisted Member
3
Rep 31
Posts |
|
Appreciate
0
|
04-10-2022, 01:10 PM | #38 |
New Member
0
Rep 6
Posts |
Sorry for jumping on the back of this post, i changed my brakes both front and rear discs and pads however after around a 1000 miles i started to get a shaking steering wheel when braking at speed so i had the front wheels off to check what was going on all seemed well but i noticed on my last mot sheet i had one advisory which was front control arms slight play but should be good for around 7000 miles so i decided to change these for new ones however now having done that i have noticed that with the window open when i brake as i enter my driveway i hear a metal clunk and if i drive say at 5mph and keep hitting the brake pedal it will do it each time any idea what this could be?
|
Appreciate
0
|
Post Reply |
Bookmarks |
|
|