Ok here is BMW new idea,,,this is the new expensive tool in the shop,,,yes we are starting to machine brake rotors when the rotors are warpped,,,me personal I don’t like this idea,,,,I never liked it when we did it along time ago when we had to remove the rotor and put them on a machine to turn the rotors,,,,now the machine comes to the car.
I have to say this is one hell of a machine,,,,I was impressed on how well this machine performed,,,these rotors had a warpage of .10 mm,,,,the portable brake lathe easily cut the brake rotor. Here is a little video of the brake lathe in action,,,,you noticed I’m now on the passengers front wheel,,,,and the brake lathe head has to rotate to the other side to cut the rotor.
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Recent Comments
bmwtechnician 
Looks very interesting, does that mean you guys will opt for recutting rotors as opposed to replacing them now ? Can this be used on floating rotors and cross-drilled rotors from the M-cars
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Yes we will be opt to turn rotors instead of replacing them,,,,,another way of saving money,,,,they say yes to floating rotors and cross drilled rotors
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I had this done on my CPO 2015 335ix as I had some shimmying in the steering while braking from freeway speeds. The on-car brake lathes used got my rotors back within spec and the cut is “true” to the hub as it’s connected right to the car. 4000 miles later and so good so far. They DID replace the front pads so that might have helped also.
I used to not like the idea as it thins out the rotor but it helps to eliminate rotor runout to true the rotor. I also had Honda do the front rotors on my Odyssey and it’s still perfect after 10k miles. Personally, I blame the selection of pad material. Most shimmys occur due to uneven pad deposit on the rotors when you brake hard and hold the brake pad against a hot rotor.
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Yes we also replace the brake pads,,,BMW is the last car company to use this system,,,,yes I don’t like it because it takes meat away from the brake rotor
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This is great stuff. My dealer quotes $1000 per axle brake pads + rotors, does it mean with this rotor lathe the price will drop to, say, $500?
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Lol,,,,good question,,,we haven’t used it for customer pay yet,,,,we have only used it for warranty repairs so far,,,it all depends how much the dealer wants to charge to use the brake lathe
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Hi Andraes, how much does this brake lathe take out, e.g. 0.5mm? BTW, my rear rotors are 20mm new, and minimum thickness is 18.4mm(or maximum 1.6mm of wear). My mechanic measured them to be 18.8mm(that means the last set of pads wore down 1.2mm), and said pads only is fine. So is it OK that the 2nd set of pads wears down the rotor from 18.8mm to 17.6mm(which is below minimum thickness of 18.4mm)?
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The brake lathe can take off less then .5mm it’s pretty cool,,,yes you are ok if the rotors go below 18.4 mm,,,as long as the rotors are above 18.4mm when pads were installed.
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Hello BMWTech,
I hope you and your family are staying safe. Tough times for everyone right now.
I have a question about brakes on my 11 328i Coupe. The brake service light came on and said I have to change my rear brakes, it says that there’s 0 miles left. However, when I went to inspect the rear brakes and there’s about 40% pad left and the sensor has not even touched the rotor yet. There’s actually a long ways to go before the sensor touches the rotor. Why is my car telling me to change brakes before the sensor is activated?
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Thank you,,,I hope everything is good with your family,,,the reason is the computer just takes a mileage calculation and try’s to figure out when the brakes are due.
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Technology has evolved to the point where the lathe should be detecting harmonics and eliminating them, thus the chatter band/brake you have installed should be unnecessary. How did you like making the cut head adjustments under the cuthead/rotor/hub/car? Did the machine tell you how much was cut and rotor thickness after the cut? Does not having the lights from the bench lathe and working in the wheel well present any challenges?
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I am not thrilled with this machine,,,but this is something BMW as recommended instead of replacing warped rotors we save money with turning a rotor,,,we don’t use a chatter band but we use little brake pads that glide on the rotor to stop the chatter when turning the rotor,,,no the machine does not tell you how much you have cut or the thickness of the rotor,,,you have to measure it yourself,,,having no light sucks,,,on the passengers side the machine is turned up side down to cut the rotor.
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