12-10-2016, 11:49 AM | #1 |
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M240i brake fluid
Hi.
I have 2 questions: 1. What's the DOT spec of the OEM brake fluid in BMW, particulary a 2017 M240i ?? DOT4 ? DOT 5 ? DOT 5.1? 2. Is it recommeded to change the OEM brake fluid for a Motul DOT 5.1 brake fluid like this ? https://www.amazon.com/gp/product/B00CMZQMKS/ |
12-10-2016, 04:44 PM | #2 |
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I've. Even trying to figure this similar thing out. For normal street use, stock fluid is all you need, but if planning on tracking at all, then something higher temp is recommended. I'm assuming factory is DOT4.
The problem With the higher temp stuff is that it needs to be replaced more frequently because it absorbs more water, quicker. But from what I've been able to find, ATE Gold is one of the better ones that's not as bad with water absorption, not quite as high temp as the others though, but still higher than stock. My question is, how much is needed to do a full flush? |
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AlexM240i101.50 |
12-11-2016, 11:37 AM | #3 |
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ATE 200 is good stuff. I like it, you should be fine with one can. But i would get two to be safe, especially if you are turkey basting the master cylinder to remove the old fluid.
I have used all sorts of full synthetic dot4 fluids. OEM, ATG Type 200, Valvoline, Johnsens. The best/most expensive fluids, have a high temperature "wet" boiling point or approximately 3.7% moisture content (industry standard calculation for 2 years of service life), vs dry which is 0% (new in bottle). Check out this fluid comparison chart thingy: https://www.lelandwest.com/brake-flu...ow=1&SF=4&ST=2 fancy baster https://www.amazon.com/Norpro-Deluxe...ter+automotive fancy brake bluid https://www.amazon.com/ATE-706202-Or.../dp/B003VXRPL0 Motul 600 https://www.amazon.com/Motul-8068HL-...ng+brake+fluid Motul 660 https://www.amazon.com/Motul-847205-...ng+brake+fluid Castrol SRF https://www.amazon.com/Castrol-SRF-R...ng+brake+fluid Johnsens's https://www.amazon.com/Johnsens-5032...+4+brake+fluid Last edited by zipphreak; 12-11-2016 at 11:52 AM.. |
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12-12-2016, 01:45 PM | #4 |
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I believe that that BMW recommends low viscosity brake fluid for the M235i/M240i due to the much higher frequency of electronic brake application required during stability control.
ATE's low viscosity fluid is SL.6 ATE SL.6 viscosity at -40C is 700 mm2/s |
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AlexM240i101.50 |
12-12-2016, 06:18 PM | #6 | |
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The Motul DOT 5.1 has low viscosity ?? |
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12-12-2016, 06:31 PM | #7 | |
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12-15-2016, 11:59 PM | #11 |
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Keep in mind that the water that is absorbed will then be working to corrode the internals of the brake system, so the track fluids that need to be changed twice as often have some additional liability for a long term driver. It can be a real PITA to keep up with all those changes, and many people get slack and just change them at the start of each season.
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12-16-2016, 12:19 PM | #13 |
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Nice Video
I have a Motive Power bleeder but have never filled the tank - only used it for pressure so it doesn't have to be cleaned. Takes more time for sure.
. Also using the ATE TYP 200 fluid -- good fluid for an OEM replacement non track . . . |
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AlexM240i101.50 |
03-20-2018, 10:11 PM | #14 |
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Track Day Fluid? Usual choices are high viscosity.
I did a car control clinic last year, and the brakes were fading badly at the end of the day. This year I want to do some more ambitious HPDE and AutoX runs, and all the forum posts say to upgrade to a track oriented fluid.
Motul RBF 600 is a popular choice (but pricey), or maybe ATE 200. But after reading this thread, I'm concerned about the viscosity of these fluids. the -40F rating for the Motul is 1750, and 1400 for the ATE 200. That's way over the ~700 of low viscosity fluids. So, are there any high boiling point DOT4 fluids that are low viscosity? Looks like ATE SL.6 is a LV fluid, with better than OEM boiling temps. But it's a long way from the track oriented fluids. Anything better out there? Or, does everyone just switch back to low viscosity fluids in the fall? (I live in Minnesota, so a -20F day is fairly normal. I'd like my ABS to work well in the snow/ice/cold.) |
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03-21-2018, 07:41 PM | #15 | |
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the expensive is the Castrol SRF for $60 https://www.autohausaz.com/pn/CA-218...SABEgKUx_D_BwE |
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03-21-2018, 08:42 PM | #16 |
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anyone here try pentosin? My shop just put some in my 2 series.
dot4lv is the product. I think it was approx $ 12/quart |
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03-22-2018, 11:24 PM | #17 | |
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Still, my serious SCCA racing brother swears by the RBF 600. And it sure seems to be the popular choice on this forum. I'm resigned to spending the money on it. My question though is still about using these very high-viscosity fluids in this car on a routine basis. The standard fluid is a low-viscosity to improve the action of the ABS and all the stability tweaks it is doing. I'm guessing that while the fluid is hot on a summer race day it's thin enough not to matter. But, on a cold rainy day, when you really need the ABS and stability control, will these high-viscosity fluids reduce their effectiveness? And especially in the winter? Anyone notice issues with high-viscosity fluids in colder weather? Do people flush back to stock low-viscosity fluids for the winter? I know that high-temp fluids should be flushed annually anyway. Guess it isn't a big deal to say they have a six month life and go back to LV fluid for the winter. Would like to know what people do. Related question. Nobody has referenced activating the ABS during a flush. Is it necessary? What if I'm going between high-temp and LV fluids? And how do you activate the ABS pumps if I want to? |
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03-23-2018, 12:24 AM | #18 | |
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04-07-2021, 07:22 PM | #21 | |
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If you run the ABS bleed procedure, it depends how quick you are opening/closing bleeders and running the process. At least 1.5 liters, and I usually use 2. That's also why I only do the ABS cycle bleed in the fall when I'm putting cheaper Pentosin LV fluid in. Don't want to waste that precious Castrol SRF. |
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04-07-2021, 11:20 PM | #22 | |
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Any chance you have the details on the procedure? |
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