So, my "backyard" mechanic decided he wanted to machine the rotors down to a flatter surface and stick in some new pads without asking while the axle and bearings were being replaced. I'm fine with that as long as it's perfectly acceptable to do this sort of thing with rotors. I just thought I'd ask you guys to find out if this is done on a regular basis. I realize that with a slightly narrower rotor, that the build up heat occurs that much sooner, but I'm not sure of the tolerance at hand. Any thoughts?

 

Machining rotors has become an acceptable standard and they all come with their own specs for minimal thickness. Made a lot more sense when rotors included the hub and a lot more expensive, but is still acceptable. I prefer not to for the cost benefit ratio. It won't hurt, but it really doesn't make too much sense at the price of non hubbed rotors either. Ooh where about in NY?

 

I'm in Westchester, just north of the city. We'll see if they're smooth enough I guess after driving around a bit. Yeah, I see that a pair of new ones can be had for less than $100. He wants $25/rotor, so it's not bad with no additional labor for the pads and machined rotors, as they were off anyway. Thanks...

 

Well, good rotors cost double that. Assuming you have good rotors to begin with, it might be worth machining them.

 

Yeah I think you'll be fine. As long as the guy does a decent job they'll be good as new. However next time you need brakes I would definitely suggest replacing the rotors rather than having them machined again

 

I'd agree on the next time, there's no way you should ever be machining rotors twice. On the other hand if you're saving that much it might be worth it tom you. As far as the good as new, well they're obviously not as they're thinner and will warp sooner. They should get you by for a while though.

 

Keep in mind Audi oem rotors are fairly thin as rotors go to begin with. If your rotors are really worn then machining them may put them out of spec. And like CCA4 says - never machine them twice.

I do have a new set of slotted ECS rotors sitting in my garage if anyone is interested.