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      07-30-2018, 06:30 PM   #23
dparm
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I'm 90% certain there's air trapped in there. Sometimes you get tiny bubbles stuck to the inside of the caliper. I saw others recommend hitting the caliper with a dead-blow hammer, which is sold advice.

I'm also vehemently against Motive bleeders. Those things cause too many problems with letting air in. I do it the old fashioned way.
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      07-31-2018, 08:37 AM   #24
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Have you tried hitting it really really hard with a 10lb hammer?
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      07-31-2018, 08:39 AM   #25
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Quote:
Originally Posted by sgreer78 View Post
Sam, Dave has a tool that can cycle ABS pumps if you decide that's what you want to do. I still think there's some issue with your rotors and those Ferodo's not getting along. Before I do my pads I'm going to have my lips turned down.
Oh yeah...my stock rotors had a lip around the outer edge when changed at 55k miles or so? Do yours have a lip on the inside or outside?

And I also have a 10lb hammer you can borrow
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      07-31-2018, 05:29 PM   #26
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I have lips inside and out. So I guess at least they're wearing evenly.
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      07-31-2018, 06:02 PM   #27
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Originally Posted by M3Post View Post
That's what she said..
She said top and bottom.
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      07-31-2018, 09:07 PM   #28
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i'll bleed old fashioned this weekend if i can. re: hammer, hit the caliper with it? no lips on the rotors to speak of, car has 26k and i assume the rotors are the originals
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      08-01-2018, 11:53 AM   #29
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will take some better pictures of the rotors when I get back from work trip.
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      08-05-2018, 11:21 AM   #30
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back from cali and checked - i'd say negligible lip on the driver's side rotor, about 1mm on the passenger's. i'm happy to get new rotors if that will fix the problem, but i think i would see some kind of wear on the pad from the rotor if that's what's causing the issue correct? i've got new oem hardware to install, but i'd like to wait to do those until i determine i need new rotors, so i don't have to take everything apart another time.

https://www.turnermotorsport.com/e/p...r-pair/?pdk=AQ

will those do?

one other thing, is there anything in the rear i should be inspecting? i've been assuming 80-90% of the pedal feel & braking comes from the fronts, so i haven't been looking at the rears all that closely.
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      08-05-2018, 10:28 PM   #31
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some pics: all the rotors have i'd guess a small amount of lip, maybe 1mm or so, I can see how this could impact pedal feel and also possibly explain why the oem pads feel ok, but i'd like to be sure before spending a grand on new rotors..













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      08-09-2018, 10:40 AM   #32
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dropped off the rotors this morning - took long because two of the rotor bolts had stripped, fucking things.

guy there said it was a reach to put the soft pedal on the rotors, which i agree with, but he said not a bad idea to turn with new pads nonetheless. hope i haven't already put too many miles on the pads. will possibly get them back on the car later tonight, install the new rubber bushings & pins onto the calipers, and rebleed etc. this weekend.
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      08-17-2018, 03:34 PM   #33
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Quote:
Originally Posted by kyoo View Post
back from cali and checked - i'd say negligible lip on the driver's side rotor, about 1mm on the passenger's. i'm happy to get new rotors if that will fix the problem, but i think i would see some kind of wear on the pad from the rotor if that's what's causing the issue correct? i've got new oem hardware to install, but i'd like to wait to do those until i determine i need new rotors, so i don't have to take everything apart another time.

https://www.turnermotorsport.com/e/p...r-pair/?pdk=AQ

will those do?

one other thing, is there anything in the rear i should be inspecting? i've been assuming 80-90% of the pedal feel & braking comes from the fronts, so i haven't been looking at the rears all that closely.

Those Turner rotors would be fine.

A 1mm lip is basically nothing. I'm not sure if there's even a spec for this, but I wouldn't worry until it's like 3mm and the pads are tapering or whatever. The rears are actually doing more work than you'd think because of how the ABS computer will use them to keep the nose of the car from diving too much. I can't remember BMW's acronym for this, but it's part of the EBD. We're still talking very small amounts of pressure to accomplish this, but it's not zero.

I would disagree with the other poster's claim about orange indicating high temps. It is basic surface rust because you have iron exposed to water and the air. Any iron rotor will do this over time unless it's coated.

At this point I don't know what else to tell you beyond rebuilding or replacing the calipers and putting everything back together exactly to spec with new hardware. You should be able to pick up a rebuilt caliper without breaking the bank. Calipers will need rebuilds eventually -- especially if you are putting a ton of heat into them at the track. I'm getting my Brembos rebuilt after about 20 track hours, for example.
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Last edited by dparm; 08-17-2018 at 03:40 PM..
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      08-17-2018, 04:05 PM   #34
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yea, turning the rotors didn't do anything. it's bizarre. i'll keep flushing i guess. only difference then is pads or fluid.

as a reminder, the only thing i changed were the pads before i immediately noticed softer pedal. i did let out some fluid at the time since i was pushing the pads back, so those are the only two variables. i've flushed a couple times now with no air in the lines but yea i will have to try the abs thing, alternatively, hit abs, flush, hit abs, flush

Last edited by kyoo; 08-17-2018 at 04:23 PM..
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      08-17-2018, 05:39 PM   #35
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Quote:
Originally Posted by kyoo View Post
yea, turning the rotors didn't do anything. it's bizarre. i'll keep flushing i guess. only difference then is pads or fluid.

as a reminder, the only thing i changed were the pads before i immediately noticed softer pedal. i did let out some fluid at the time since i was pushing the pads back, so those are the only two variables. i've flushed a couple times now with no air in the lines but yea i will have to try the abs thing, alternatively, hit abs, flush, hit abs, flush

BMW doesn't even recommend turning the rotors due to the decreased mass resulting in less thermal capacity.

It's entirely possible that you damaged something when changing the pads, or by coincidence, the calipers are starting to fail.
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      08-20-2018, 08:50 AM   #36
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Quote:
Originally Posted by dparm View Post

It's entirely possible that you damaged something when changing the pads, or by coincidence, the calipers are starting to fail.
That would make sense if the OEM pads felt soft too, but only the Ferodo's are giving him trouble.
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