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BMW 3-Series (E90 E92) Forum
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Crazy brake judder - about anything is replaced...
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10-14-2021, 07:38 AM | #45 |
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Drives: e91 330d m sport pre-facelift
Join Date: Aug 2011
Location: middlesbrough
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I had exactly the same problem for years replaced every thing twice and some !! The problem was guide pins being greased and bmw state they should not be greased in big bold capital letters as brake dust and road dirt gets stuck to grease and eventually hardens on the pins cease up causing caliper on the insides to push and stick to the inside of the discs pushing the wheels toe in !!! Look at the tread on rft’s there’s Olmsted a waves uneven pattern on the outside of the tyres this is more prominently visible on non rft’s , by the time the shudder stands the discs and possible control arms thrust arms drop links may be damaged so changing pins will not help unless discs and pads are changed at the same time and any damaged arms/links are changed first aswell it’s a £20 fix if you change them every couple of months and if you park up using hand brake only and not auto “P” which locks the discs on preventing pad debris sticking , hope this helps guys
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10-14-2021, 07:49 AM | #46 |
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My e90 does not need brake service often, but when it does I use 100% OEM parts and throw the old guide pins in the garbage where they belong. My braking has been absolutely perfect in this car every day. Yes the BMW pads put out some black dust, but they are nowhere near as bad as the OEM pads from years past (cleaning off BBS basketweaves was a real chore). I suspect most of the problems above result from crappy pads or incomplete brake jobs, or the damage resulting.
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10-17-2021, 10:29 AM | #47 | |
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10-17-2021, 04:54 PM | #48 |
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I drive a BMW 1M which as you'll know has all the same brake components as the E92 M3 and am also getting this hot vibration issue. Brakes are smooth as silk when cold, but drive hard for a few miles and the judder starts and only gets worse the hotter the brakes get. Nothing through the peddle, but violent shaking of the steering wheel which gets increasingly worse to the point where you can barely hold on to it. Makes the car totally unenjoyable to drive.
I am actually a brake design engineer by trade, I spent the last 7 years designing EBC's new line of brake calipers and 2-pc brake rotors. So I'd hope I'd be able to get to the bottom of this one and correct the issue. Firstly brake discs dont 'warp'. It is however possible to have run-out, but run-out is not temperature dependent.... if the discs had run-out the vibrations would be there whether cold or hot. Temperature dependent vibration is nearly always due to un-even pad deposits, because the 'transfer layer' deposited on the brake discs can break down if things get too hot. But I've ran thermocouples on the discs and know that on the 1M front discs peak at 460C on track, so on the road the discs are probably 300-350C max, which is very cold for performance brakes. So I'm very confident the brakes aren't overheating, and besides usually you can see uneven pad deposits with the naked eye (dark splodges around the disc). In my experience the problem is likely one of 2 things: 1) the calipers are binding/not sliding freely, causing hot spots on the disc which leads to an un-even transfer layer when these localised hot-spots get extremely hot 2) the brake disc is simply a 'bad' metallurgy and just doesn't allow the pad to bed-in properly to the disc I grease the caliper sliding pins every pad change, which for me is often as I'm regularly running new developments of pad materials. I'd say the sliding pins are greased every 1,000 miles or less, but even still every time I do a brake job the sliding pins on the front calipers are always very sticky. The front calipers never slide freely, whereas the rears always seem to slide free. Inevitably this will be due to front brakes experiencing higher temperatures when pushing hard, which might be effecting the grease on the sliding pins. Essentially the calipers fitted to the 1M are very basic/low quality single piston sliding calipers. For sure they should never be fitted to any high-performance car and it's no wonder so many owners choose to upgrade to a multi-piston fixed caliper design... however I've driven plenty of other cars very hard on track and those all had sliding calipers but never experienced this hot judder problem. So why does it seem to effect BMW's more than other cars? Which leads me to believe the brake disc itself is partly to blame. Either it's as simple as 'bad' metallurgy, or it could be to do with the pin-drive disc design which may distort unevenly with temperature (different to warping because warping means permanent deformation even after heat is removed). Over the coming months I will design a new front BBK for my 1M based around EBC's new 6-piston caliper. I'll also ditch the BMW pin-drive front discs and instead replace with a 2-piece fully floating disc which is the sort of thing you see on serious performance cars (Nissan GTR, Aston Martins etc.) My suspicion is simply that the OEM calipers/discs simply aren't able to cope with prolonged sporty driving. Sure everything might work fine for 'normal' (slow) driving, and might even work fine for the first few hundred miles of 'sporty' driving. However it seems pretty clear to me, even with a very well maintained brake system, the OEM hardware simply can't cut it. Fitting a front BBK might seem like using a sledgehammer to crack a nut, but if you add together the cost of relentlessly replacing discs/pads/calipers then it would pay for itself pretty quick. And I love everything about my 1M, except the brakes suck so bad it actually is ruining the car for me. I will not be changing any suspension components, tyres, getting wheel balanced etc etc etc... none of that stuff because honestly I'm pretty convinced none of that is relevant to a HOT brake judder problem. More to follow soon |
10-17-2021, 05:33 PM | #49 | ||
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Curious if anyone with upgraded less compliant control arm bushings has seen this (I expect not). And also if the problem also shows up with higher performance brake pads with stock bushings (I expect it has). Quote:
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10-18-2021, 07:20 AM | #50 | |
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10-18-2021, 07:23 AM | #51 | |
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10-18-2021, 08:57 AM | #52 | |
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12-06-2023, 07:43 PM | #53 |
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Any updates?
Has anyone nailed down any more ideas for where this judder might come from?
It's a big problem on my 2006 325i - and has been for years. Every time I replace pads and rotors, braking is great. Then about 1000 miles later, I get a slight shake while braking that builds over the next 1K miles until it's a fairly violent judder that appears at certain, but not, all speeds and times. It's super weird though - the judder is ONLY during braking, but the strength and severity seems variable. Sometimes if I'm coming from to a stop from highway speed, there's violent shaking from 60-20 - then goes away from 20-0. Other times, at lower speeds, it's there from 40-0 all the way. How hard I brake doesn't seem to affect things much. My indy's stumped, and we've tried different brands of pads and rotors, but it always comes back. I've tried babying new pads and rotors, and I haven't tracked the car in years... I know the car's old, but it's a disconcerting problem... |
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12-07-2023, 08:52 AM | #54 |
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This may sound and probably it's stupid, but if everything has been replaced with assuming good parts, could be a problem related to the caliper carrier? After a lot of heat cycles of cold/hot/cold, could this over time "relieve" some stress in the metallurgy of the carrier leading to a slight twist/torsion (tenths of a millimetre / 0.004 inches) that leads to the guide pins not being perfectly parallel between each other or between the carrier and the disc and so making the brakes shake?
Last edited by PhaceN52; 12-07-2023 at 09:38 AM.. |
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12-07-2023, 03:28 PM | #55 | |
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The vibration was very very similar to a cellphone in your pocket, quick but smooth vibration, not heavy. It happened only when hot, like after a mountain driving with heavy slopes. When cold all good. So my assumptions were the fluid was boiling, until I hand touch the caliper after a rough ride, and they were warm. No way the fluid can boil. One day I got heavier vibrations noise and noticed the caliper was moving. In deed, it was the aftermarket studs under heat , got longer and the caliper became loose. They are made for heavy use, and used for brembo BBK conversion by many driver... re-torque, then blue Loctite. did not worked. I simply used red Loctite and over torque those stud, for now all good, if it ever come back, no choice to replace those studs. |
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