Help with squeaky brakes

[Yobao]

Hey guys,
So my E92 has been developing a bad brake sqeak recently. I bought it 2 months ago with aftermarket stainless steel line. I did not notice any squeaking until about a month after I got the car. I brought it into a BMW dealership and they thought it was the front brake rotors which has about 2K before it needed to be changed. The dealership swapped it out. I took it home and it was still squeaking. So I brought it back to the dealership and they said that it was due to warped rotors. My service advisor says that they were about to not honor the waranty because I had the aftermarket brake lines. They state that the line maybe causing too much heat during braking process thus warping the rotors. They went ahead and changed the two front rotors. The sweaking stopped in the front but minor squeaks were still heard in the back brakes. The squeaking is getting louder. The squeaks only comes on when I'm gently braking. Sometime the squeaks can also be heard at low speed (5-6miles/hr) without me touching the break pedal at all!
I want to know if you guys have any of these problems before. Should I swap out the stainless steel line for the OEM? It seems like I would have to if I'm going to get BMW to honor the waranty. The squeaking is really annoying and embarassing . Any advise would be appreciated. Thanks

[C|3R1C]

I've never read anything about SS lines causing squeaking but I do know if you use your brakes lightly, a slight film of brake dust can coat the rotors (aside from the normal transfer of material) and cause squeaking. Have you tried braking really really hard a few times to clean the rotors and pads?

[rzm3]

I really don't see any reason why stainless steel brake lines would cause your brakes to make noise. One of the easiest solutions is to use anti squeal pastes. Available from Autozone. I believe that BMW is also supposed to use it when replacing brake pads. Part number 81 22 9 407 103.

[Yobao]

cool, will try both methods and update to see if it works. thanks

[BimmerRob08]

Are the brakes all OEM, except for the brake lines? The brake lines would not cause the squeel. In my experiance with all brakes, squeeling comes from a build up of brake dust and it kinda glazes on the brake pads the only way to get rid of the squeel is to go do a brake run-in. Swopping rotors and pads will clear the squeel too unless it's metal to metal type squeel then it would be more of a grinding sound from like a pad wear indicator or something.

I've had this on my 2004 Saab 93 Aero, even my OEM M3 brakes for a while, my AP's, my dads Alfa Romero in all cases it was caused from light braking over time. So then I'd go do a brake-run in (repetative 50mph to about 10mph gradual braking to harder braking) this causes the brake pad material to transfer onto the rotor disc and clear the pads of glazed brake dust.

check out StopTech's or APracing's brake run-in procedures. If you do something of the kind, I think it'll clear the noise out for a long while, plus improve braking.

This of course is if it's just brake dust build up or the pads getting glazed. Disc warping would cause severe vibration in the steering wheel and/or felt in the pedal while braking. I don't think that is what you have from what you mentioned. I think its just the pads need to be run-in with some hard braking intervals.

Good luck.

[Car54]

Changing the lines back to stock isn't a bad idea either. There's more reports of incidents with crappy SS lines than there are with good condition OEM. If you don't ever plan to take it to the track...just swap them to OEM next brake flush.

EDIT: I don't feel that the brake lines cause any more heat. If you have a bunch of maintenance time left, best not to mess with the dealer techs on the wear items.

[M3PO]

It's not the lines and rotors. And rotors don't "warp". Brake vibration is caused by uneven pad transfer.

It's related to the pads. Use some anti-squeal lube (like ATE plastilube) to lube the back side of the pads and the pad slides. Also, make sure the dust/gas slot in the pad is not caked with dust.

[m3an]

Originally Posted by C|3R1C

I've never read anything about SS lines causing squeaking but I do know if you use your brakes lightly, a slight film of brake dust can coat the rotors (aside from the normal transfer of material) and cause squeaking. Have you tried braking really really hard a few times to clean the rotors and pads?

Originally Posted by RLDZHAO

I really don't see any reason why stainless steel brake lines would cause your brakes to make noise. One of the easiest solutions is to use anti squeal pastes. Available from Autozone. I believe that BMW is also supposed to use it when replacing brake pads. Part number 81 22 9 407 103.

lines don't and wouldn't be the issue but come on guys common sens= it's the dealers easiest way to get out of repairs and turn the customer away as they can deny repairs/warranty due to the item not being OE

[C|3R1C]

Originally Posted by m3an

lines don't and wouldn't be the issue but come on guys common sens= it's the dealers easiest way to get out of repairs and turn the customer away as they can deny repairs/warranty due to the item not being OE

Yea that was my first thought.

[BimmerRob08]

Originally Posted by m3an

lines don't and wouldn't be the issue but come on guys common sens= it's the dealers easiest way to get out of repairs and turn the customer away as they can deny repairs/warranty due to the item not being OE

I agree too. If they know they can BS someone that isn't as Auto savey, they'll try to blame it on something to get out of paying for it. But even though, one could argue that changing the brake lines to non OEM will ony void the warrenty on that part, which is how it should be. Not blame the line for something that they know is totaly unrelated to the issue.

[Car54]

Originally Posted by Willard1

There are three factors can affect it, brakes pad produce a lot of dust, the rotation between rotor and brake pad, drive a few days to let them settle down or is time to adjust your brake pad.

How do you do that?

[nbennettksu]

The OEM pads and rotors are a soft metal. They're noisy and dusty. Heat, moving parts... friction. Its gonna happen.

Originally Posted by Car54

How do you do that?

I think he was joking. Unless he is referring to the e-brake... but I believe the E9x self-adjusts; unlike the E46 which had to be manually adjusted.