07-30-2021, 08:57 AM | #1 |
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Factory brake issue?
My 2017 530ix (29k) had pulsing brakes. Dealer said it was warped rotors, and machined them to be true again (at my cost). Pads were fine, and not changed.
Since then the brakes have been very soft, and occasionally I really have to really press down on them to stop in the usual distance (pre-machining). Two questions: 1. Warped rotors at 29K? Normal driving (60m a day/highway). Is this an indicator of a brake system problem? 2. Do I need a certain "break-in" time to get the pads reseated and the brakes to perform like BMW brakes again? Thoughts on why they are not performing as before after the rotors were trued. Air in the lines? Thanks for the help. |
08-03-2021, 04:50 PM | #3 |
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Rotor warping is rare... only measurement of run out would tell for certain. More likely you had brake pad deposits on the rotors, which can be removed (usually) through a series of hard stops. Machining will take it off as well...but if they were warped, they are more likely to warp again, now that they are thinner...assuming the same conditions that cause the warping is still present.
IF your rotors where warped, a visual inspection of the pads is warranted, to ensure they were not overheated or glazed. When was the last time your brake fluid was bled? Per BMW, it should be done at year three, then every other year there after. So with a 2017, you should have had your brake fluid changed sometime in 2020 depending on your inservice date |
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08-10-2021, 12:14 PM | #4 |
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I have a CPO 540i that just crossed 30k that I've had for maybe 2 months. My steering wheel would vibrate while braking when I hit 30mph.
I set up an appointment and the service rep immediately said "oh it's a warped rotor, they are very soft" I've had several BMWs with M Sport package and never had 'soft rotors' before or needed brakes so quickly. The pads had 70% life still on them. He explained later that they develop 'hot spots' in the rotors usually from auto-crossing or just lots of frequent heavy braking which is what causes the pulsation. They replaced all pads and shaved all the rotors and also bed the brakes. If I keep the car long enough, I'll likely upgrade the rotors.
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08-10-2021, 01:37 PM | #5 | |
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Rotors can warp, but it is probably less than half the case. https://www.motortrend.com/how-to/18...ed-rotor-myth/ https://blog.fcpeuro.com/warped-brak...-internet-myth |
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08-12-2021, 09:37 AM | #6 |
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FOLLOWL-UP
Thanks for the input. The brakes did seem to get a bit better with use, but still not great. Went back to BMW and had the fluid changed. Now they are working fine. Am looking to upgrade to M-Sport brakes when the pads are shot. Any thoughts/guidance? Thanks again ! |
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11-26-2021, 06:16 PM | #7 |
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2018 540i non msport
around 35k miles, my front rotors starting pulsating and very quickly became very warp. I bought new rotors, bmw brand, installed and now I have pulsating after around 18k miles of use. I resurfaced the old rotors which still had enough meat left and they are sitting in my garage. I will most likely install them, resurface the 2nd set and keep them on hand for when the 1st set warps again. Kinda bs but whatever. what are good upgrade options? |
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11-26-2021, 06:51 PM | #8 | |
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12-01-2021, 06:00 AM | #9 |
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I've been looking on Brakenetic's website and I can't find any Slotted Rotors for M sport brakes. What are the part numbers you used?
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12-01-2021, 06:28 AM | #10 | |
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12-27-2021, 11:16 AM | #11 |
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The only vehicles I ever had warped rotors on were:
1 - loaner/rental cars 2 - My wife's X5 after about 70k miles For my wife'x X5 resurfacing fixed the issue for about 40K miles but now it's back. The only vehicles I've had warped rotors on <70K miles were rental cars. I had one at about 4k miles with warped rotors. |
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