E90 rotor machinable?

samchuang33 · 06-18-2013, 07:37 PM

Hey guys

My brakes are squeaking constantly at low speeds and after inspection we found the rotor has a obvious lip on the outside edge.

Can BMW rotor be machine?

Stuart@BMRAutowerkes · 06-18-2013, 08:17 PM

Quote:

Originally Posted by samchuang33

Hey guys

My brakes are squeaking constantly at low speeds and after inspection we found the rotor has a obvious lip on the outside edge.

Can BMW rotor be machine?

they're not meant to be... depends how much life left in the rotor though.

samchuang33 · 06-18-2013, 08:39 PM

Quote:

Originally Posted by Stuart@BMRAutowerkes

they're not meant to be... depends how much life left in the rotor though.

According to on board computer, front has 60,000ks left and rear 30,000. The pad still have more than half left and the disc should be still ok for another 20,000ks if not more.

_ink · 06-18-2013, 10:25 PM

I believe all rotors are machinable, however it's best to take it to your mechanic for a visual inspection as they will be the ones machining it.

kaitan · 06-18-2013, 11:06 PM

You can machine the rotors but provided that the rotors are still within the legal limit in thickness after machine.

samchuang33 · 06-21-2013, 02:03 AM

Thx guys.

I try to see if thickness permits machining.

DR-JEKL · 06-21-2013, 02:54 AM

Just because your rotor has a lip isn't the cause for your squealing, its most likely due to your pads/shims.

As the guys have mentioned, the min thickness is specified on the rotor itself on the cast marks (by memory the 335i was around 28.6mm and the 325i was 22.6mm min thickness)

You need a pair of micrometers to measure the thickness of the worn portion of the rotor, as there is usually a lip on the very outside edge (the pad doesn't contact the very edge of the rotor) which means you cant get a set of verniers in to measure the thickness.

Also don't always rely on the idrive, as it isn't entirely accurate!

mmmmQuattro · 06-21-2013, 06:45 PM

That wear lip isn't uncommon. How many km's have you done? Also, do you do a lot of stop / start driving.
We had to change our rotors at about 32km. Cost about $1000.

06-18-2013, 07:37 PM	#1
samchuang33 Captain 38 Rep 780 Posts Drives: MY 16 440i & MY20 X7 30d Join Date: Feb 2009 Location: Brisbane AUS iTrader: (0)	E90 rotor machinable? Hey guys My brakes are squeaking constantly at low speeds and after inspection we found the rotor has a obvious lip on the outside edge. Can BMW rotor be machine? __________________ 2020 BMW G07 X7 3.0d M Sport 2018 Audi FY Audi SQ5 2016 BMW F36 440i GC M Sport
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06-18-2013, 10:25 PM	#4
_ink Jedi samurai ninja turtle 619 Rep 3,021 Posts Drives: X3 M40i 2018 Join Date: May 2012 Location: Sydney, Australia iTrader: (0) Garage List 2018 X3 M40i [0.00]	I believe all rotors are machinable, however it's best to take it to your mechanic for a visual inspection as they will be the ones machining it.
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06-18-2013, 11:06 PM	#5
kaitan Lieutenant Colonel 73 Rep 1,546 Posts Drives: The Dark Side VAG TDI Biturbo Join Date: Nov 2011 Location: sydney, australia iTrader: (1)	You can machine the rotors but provided that the rotors are still within the legal limit in thickness after machine.
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06-21-2013, 02:03 AM	#6
samchuang33 Captain 38 Rep 780 Posts Drives: MY 16 440i & MY20 X7 30d Join Date: Feb 2009 Location: Brisbane AUS iTrader: (0)	Thx guys. I try to see if thickness permits machining. __________________ 2020 BMW G07 X7 3.0d M Sport 2018 Audi FY Audi SQ5 2016 BMW F36 440i GC M Sport
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06-21-2013, 02:54 AM	#7
DR-JEKL Major General 898 Rep 6,285 Posts Drives: Space Grey E92 335i 6MT Join Date: Jul 2012 Location: Newcastle Ozstraylia iTrader: (3)	Just because your rotor has a lip isn't the cause for your squealing, its most likely due to your pads/shims. As the guys have mentioned, the min thickness is specified on the rotor itself on the cast marks (by memory the 335i was around 28.6mm and the 325i was 22.6mm min thickness) You need a pair of micrometers to measure the thickness of the worn portion of the rotor, as there is usually a lip on the very outside edge (the pad doesn't contact the very edge of the rotor) which means you cant get a set of verniers in to measure the thickness. Also don't always rely on the idrive, as it isn't entirely accurate!
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06-21-2013, 06:45 PM	#8
mmmmQuattro Major 259 Rep 1,165 Posts Drives: f83 / E93 335 / E70 X5 40d Join Date: Sep 2007 Location: Adelaide, South Australia iTrader: (0) Garage List 2007 320 E91 M-Spor ... [0.00] 2009 335-E93 M-Sport [0.00]	That wear lip isn't uncommon. How many km's have you done? Also, do you do a lot of stop / start driving. We had to change our rotors at about 32km. Cost about $1000.
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