09-29-2023, 01:48 PM | #23 | |
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I tried to verify your statement about their being a different master cylinder and brake servo on the F-335i depending on which of the two brake packages are on the car from the factory. When there are different part options for a car model, then realoem shows them. For example realoem shows the different calipers, rotors and pads for the two factory brake configurations that I mentioned. But for the master cylinder and brake servo, realoem only shows one part number for each for my model. (34336851095, 34336851098) So my F-335ix would receive the same master cylinder and brake servo regardless of whether it came from the factory with standard brakes or the factory option M Sport Brake package. I also looked up on Realoem an F80 M3 built the same month as my car. It has completely different part numbers for master cylinder and brake servo. (34337849878, 34337849876) Note: Sometimes different model cars use different part numbers because one is more heavy duty or an improvement. But that doesn’t mean that they are interchangeable. It is important not to automatically make that assumption. Just as often there is a completely different reason for a different part number like a different parts supplier, a clearance issue or some compatibility issue that may not be obvious. The most common reason for brakes not performing 100% after brake component replacement is that a full fluid replacement with a brake bleed following the BMW ISTA procedure was not done. Air bubbles cling to the inside walls of the brake system, using ISTA is the only way to shake them loose, to then bleed them out. See FaRKle! video below. https://youtu.be/o7XsCMqZXw0?si=jndNITBrmeb4H-iZ |
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10-02-2023, 09:40 AM | #24 | |
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I am currently on the 340/345 combo and wonder if I should VO code SPBR into the car, as some coders have reported a more linear and immediate brake effect.
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10-02-2023, 10:27 AM | #25 | |
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My brakes are so responsive that I don’t want to mess up a good thing by playing around with coding them. It’s a BMW. I always have a list of things to do! |
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10-04-2023, 05:28 AM | #26 | |
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10-04-2023, 07:10 AM | #27 | |
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10-04-2023, 07:21 AM | #28 | |
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Fingers crossed it's sorted now. Just waiting to take it in. |
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10-04-2023, 09:20 AM | #29 | |
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10-04-2023, 10:41 AM | #30 |
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10-04-2023, 01:35 PM | #31 |
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SPBR = proper coding if you've only retrofitted calipers
2NH = if you swapped master cylinder. technically I believe S2NHA comes with reinforced brake lines as well from factory. So you should probably KEEP SPBR and REMOVE 2NH Last edited by rlesko; 10-04-2023 at 07:04 PM.. |
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10-05-2023, 04:55 AM | #32 | |
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Thank you |
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10-05-2023, 08:41 AM | #33 | |
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I coded SPBR with the following set up: stoptech SS brake lines, stock 4 piston brembo up front (340mm rotors), retrofitting 2 piston rembo in rear (345mm rotors). The car feels good and performs even better. |
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10-06-2023, 07:14 AM | #34 |
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Had the master cylinder replaced with one compatible with M-Performance brakes. Coded out 2NHA and only left SPBR on. Still nothings changed
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10-06-2023, 10:47 AM | #35 | |
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It was a bad idea IMO to change the master cylinder. Now you've introduced a ton of air into the system and you need to run the ISTA brake bleed procedure. Did you do that? Last edited by rlesko; 10-06-2023 at 10:52 AM.. |
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10-06-2023, 05:42 PM | #37 | |
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In any case, the path forward is to run the ISTA brake bleeding procedure and ensure only one of SPBR and 2NH is coded. |
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10-07-2023, 10:54 AM | #38 |
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I tried to skim this but I think there is a lot of misinformation or misunderstanding of how these brake systems work.
If you increased the volume of the pistons compared to your original brakes (you did) then your pedal travel will be longer no matter what you do. You're having to move a higher volume of fluid to achieve similar piston position/force. A lot of people assume the M perf brakes MUST improve brake feel because "performance!". But that's no the case. They are higher volume with more pistons/surface area and thus have a "looser" feel. Now, most of this is actually controlled by the takeup cylinder within the mastercylinder assembly. This is a cylinder that is relatively large and it's valved so it "takes up" the dead zone rapidly by moving a lot of fluid. Then when the pads start making contact and pressure builds, the actual master cylinders are used which are significantly smaller diameter. That gives you hydraulic leverage to apply more force to the pad for the same pedal force. Additionally, pads can have different feels relative to eachother with some feeling softer than others. And new pads that aren't bedded will also feel softer still. New lines don't contribute much to the feel. Those are mostly bullshit and I'd recommend just sticking with the stock lines. If you truly don't like the feel still, then I recommend you get a new master cylinder from an M3 or M4. I haven't done the research for the F chassis cars but on E90/82s the 1M/M3 cylinders are a direct swap and have a pretty big takeup cylinder that feels great. The real question is what master cylinder did you swap in? Unless it had a larger takeup then you're still going to have shit feel.
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10-07-2023, 11:17 AM | #39 |
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I’ve put in a master cylinder from a BMW M4 Competition. I know the m performance brakes have a bit more travel but this sinks to the floor!
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10-07-2023, 12:31 PM | #40 |
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10-07-2023, 12:46 PM | #41 | |
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Ok in this case you likely have not filled the system properly. I would do a couple cycles of INPA bleed then traditional bleed with full liter of fluid. Maybe do this a couple times and go through 2L. It's overkill, but there's no way air remains after this. use something decent like this https://www.amazon.com/ATE-706202-Or..._t1_B07338GQM8 Also are you bleeding both sides of the brakes? The performance brakes each caliper has 2 bleed screws. And the screws must be on TOP. If they are not on top, the calipers are on the wrong side (not even sure this is possible to fuck up).
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10-07-2023, 01:42 PM | #42 |
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What are the last 7 digits of your VIN? I looked up a generic 428i on realoem and got the exact same master cylinder as my 2015 335ix which is part# 34336851095. There was no difference in master cylinder if your car came with M Sport factory brakes or not. I need the VIN to verify this for your exact car.
The F8x and F3x are different models. Although a small number of parts are used on both and sometimes mounting holes line up, it doesn’t mean that F8x parts will work on an F3x. And it doesn’t mean that F8x parts are an upgrade for F8x parts. Factory rubber brake hoses will balloon slightly with brake fluid when the brake pedal is initially applied. This causes a slight delay before pressure is actually applied to brake pads. As rubber hoses age they tend to balloon more which causes more brake pedal delay. The stainless steel outer sheath on a brake line both protects it from road debris and prevents any ballooning. So there is no delay and pedal application goes immediately towards activating the pads. I’ve always used StopTech stainless steel lines but any high quality brand will work. Besides StopTech there are also F3x lines by Turner, ECS and European brand Goodridge. If one is out of stock you should be able to find another. See photos for some part numbers. Please post last seven digits of your VIN? |
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10-07-2023, 02:11 PM | #43 | |
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To answer your question "not even sure this is possible to fuck up", yes it is. I've seen photos posted on the UK Sub-Forum of BMW M Sport calibers which were installed upside down by a 'shop. Bleed nipples at the bottom of calibers is obviously going to make calibers very tricky to bleed.
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10-08-2023, 04:56 AM | #44 | |
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My pal had this in his shop the other day; someone had their ITR DC5 fitted with the K24 engine and all new brakes all round (some sort of concoction of Porshe calipers rather than sticking with the OEM ones) and kept having issues Had it trailered up to my pal and that was the first thing they saw when they took the wheels off in readiness to drop the engine etc... All 4 corners with the lines in to the top, bleed nipples at the bottom...
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