04-23-2016, 11:05 AM | #1 |
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Doing a pad swap, what is this white stuff?
Don't understand what this is, never seen it before. I am taking it out best I can but it's really in there... shouldn't affect anything in terms of vibration or braking, but it might be preventing proper cooling.
Not on the outside but on the inside.... weird... Anyone know what it is? Some factory paste or something? -J
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2019 BMW F36 440i w/MPerformance things
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04-24-2016, 06:58 AM | #3 | |
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04-24-2016, 10:10 AM | #4 |
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That's a genius place to hide cocaine.
OP: Your dealer must have applied anti-squeal paste on it.
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04-24-2016, 11:09 AM | #5 | |
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.... LOL that would be an awesome spot
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If this isn't normal I wont worry about it and just tear it out. Thanks! -J
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2019 BMW F36 440i w/MPerformance things
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04-24-2016, 11:46 AM | #6 | |
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Anyway, what do the pads from the cruddy side look like? I've never seen anything quite like that before and it looks as if there has been uneven contact with the pistons. Whatever it is, I'd suggest using distilled water (de-ionized on the rare chance it's accessible) in a kettle steamer and blast the Pistons clean. Last edited by lemetier; 04-24-2016 at 11:51 AM.. |
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04-24-2016, 12:20 PM | #7 | |
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I am going to take it out, I have de-ionized distilled, a few jugs, at my disposal. Thanks!
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2019 BMW F36 440i w/MPerformance things
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04-24-2016, 12:38 PM | #8 |
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Well this sucks. The white stuff might actually be some corrosion from the pistons! The inboard pistons on both sides are chipped / corroded a little on the contact surface and some on the inside. There's still a solid contact surface but.. wow. You can see it a little in the pics above.
Cheap Brembo garbage.... Looks like I am going to have to rebuild the calipers in the coming months. I am not certain whether there's paste which caused the corrosion eventually, or the pistons corroded causing the white stuff. Either way... not good. -J
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2019 BMW F36 440i w/MPerformance things
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04-24-2016, 02:00 PM | #9 | |
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The tension springs can become encrusted with gunk and as the pad wears down, the pistons are unable to maintain contact with the pad. Magnesium/Sodium Chloride makes its way in and at 150c and high moisture content, becomes reactive enough to destabilize the stainless and starts galvanic corrosion. The aluminum caliper then acts as an anode and begins to pit as well. The sodium, other electrolytes, and all the reactive metals in the brake dust are in a perfect environment with lots of surface area in a small space, creating a nasty mess. They'll need a complete rebuild and refinish at minimum, though it appears the caliper corrosion might have penetrated into the bores. If you're under warranty, it's something a dealer should look at and cover. It's impossible to clean the tension springs without removing the wheels so this really shouldn't fall back on the customer. Last edited by lemetier; 04-24-2016 at 10:30 PM.. |
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04-24-2016, 07:43 PM | #10 |
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Thanks for the detailed response and thank your friend at Brembo for me. Yep I'll have to do a rebuild. They should be covered by warranty but I wonder what BMW will say when I worked on my own brakes? Hopefully not a problem.
Unbelievable. -J |
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04-24-2016, 08:59 PM | #11 |
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put back on the stock pads, take it to dealer and tell them you have a vibration. let them see for themselves. that way they can't say u messed with the brakes. that is some fugly stuff for sure though. and quite frankly unacceptable on a 100k car.
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04-24-2016, 11:09 PM | #12 | |
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To be fair, my dealership is pretty good. I'll talk to them and work something out I am sure. There's no WAY I am the first person with this issue. I'm pissed too because I clean my brakes every time I switch wheels for season change. If it is indeed the tension spring causing this, I wonder if you can run without it? -J
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04-24-2016, 11:45 PM | #13 | |
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If you have a good relationship with a service advisor and only one caliper had the issue or both did and you've cleaned the residue off both, it could be worthwhile to go with the car and show the photos. If you don't have a comfortable relationship, it still may be worth it, but I wouldn't take the car. It really is a situation where cleaning is a problem, but more from the point that it's a location that is almost impossible to get any effective cleaning action into without an unreasonable amount of effort. If they deny the claim for any reason, you'll be stuck with a dealer rate rebuild minimum and possibly full caliper replacement. They wouldn't reinstall those Pistons and they'll have to come out to check. It's difficult to really gauge what's happening with the caliper, but there are spots that look as if they might have corrosion under the electroplated protective and finish layers. If it hasn't entered the bores,(rubber is an effective insulator but has varying capacity depending on the decay rate and its own composition). A bath in de-ionized, ph neutral, hydrophobic for the disassembled caliper, followed by a high-temp nano clear coat will do a sufficient job of sealing it off. If there is pitting in the bores, this particular caliper is right at the limits and reboring/sleeving isn't recommended. It's also not a huge cost savings compared to the deals that can be had from vendors/members on here. |
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04-25-2016, 12:03 AM | #14 | |
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If that buildup had been there long term, Pistons would have begun to seize in retracted and extended positions. The sound and feedback through the wheel would have been noticeable. The tension spring is necessary and the dampened pads help since they vibrate the spring to harmonically balance out squeal. |
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04-25-2016, 09:36 AM | #15 | ||
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It may not have been there long term, but I've noticed a slight deterioration of braking performance over the last few months. I am wondering if I should get the vibration dampers... Might be worthwhile. I'll let you know what happens. Thanks! EDIT: I should mention as well I just have stock wheels. Everything stock, until now as I've put on Carbotech pads, SS lines, RBF600 fluid. Sucks that I'll probably lose a L of that stuff re-bleeding :/ -J
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2019 BMW F36 440i w/MPerformance things
2021 BMW X3 M40i - For Sale 2003 BMW E46 M3 - Track toy 2016 Ford F250 Diesel - Carries things 2019 BMW F90 M5C - Sold and I regret it Last edited by darkrabbit; 04-25-2016 at 10:16 AM.. |
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