Machining Cross-Drilled Rotors
#1
Fleet of Foot
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I've got some Zimmerman cross-drilled rotors on my S4 and I need to have the fronts resurfaced as I have hit the pad sensors and am installing new pads. Imagine my surprise at the apparent crime against humanity (and brake lathes the world over) for having the temerity to ask a few local chains to mount 'em up and do this job for me! "MY GAWD MAN! Our brake lathe will simply self-destruct!!!!!11!!" was the typical response. My rotors do not have a ridge on them, the holes are champfered (not that it matters) and probably only require the removal of a few thousandths of material to clean them up. These idiots, and I use that term unapologetically, claim the cross-drilled holes will ****** the milling bits from their mount and cast them into the bowels of hell. My reply was: 'well sure enough if you let the idiot savant apprentice in your back room ram the bits into the rotor and attempt to remove .060" from each side in one grand sweep! My next call from you would be to inform me that I need new rotors.' I worked several years for an independent shop and resurfaced more of these kinds of rotors than I care to remember, I even offered to show one of these "professionals" how I did it. No takers, hmmm....
Anyone else encounter this kind of flak with these kinds of rotors? Yes I know the cons wrt resurfacing any kind of rotor but believe me, these have plenty of life left in them, as long as they are properly machined, and I am not hard on brakes (front pads made it >60K).
Alas my quest continues...
Thanks for allowing me to vent.
Anyone else encounter this kind of flak with these kinds of rotors? Yes I know the cons wrt resurfacing any kind of rotor but believe me, these have plenty of life left in them, as long as they are properly machined, and I am not hard on brakes (front pads made it >60K).
Alas my quest continues...
Thanks for allowing me to vent.
#2
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I'd go to a better equipped shop.....tools and personel.
I did have a GM head mechanic tell me the OEM rotors were the hardest he had ever tried to resurface
I did have a GM head mechanic tell me the OEM rotors were the hardest he had ever tried to resurface
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#5
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Hah... I was just thinking mine needed resufacing as i did my pan gasket the other day, and I was also thinking the local shop might **** and moan about them being x-drilled.
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#9
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I do not remachine my rotors every time I change the pads--only when I have enither scored them , which is rare, or they have developed a surge from wearing unevenly somehow. The new brake pads will seat to the previous worn face very readily.
Jerry Feather
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#10
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They can be resurfaced but by having them ground instead of turned. Any shop that can do flywheels can do your rotors. From a shops perspective, why make several light passes when they can do several sets of rotors in the same amount of time? And of course if they do get a bit carried away, it will destroy their equipment and you won't like the finish anyway.
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#14
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More than a few rotor edge lips have been taken off by that method. There's no way to get them guaranteed flat, but at least the new pads don't hang on that nasty 1/8" lip...
#15
Under the Lift
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You can't see the backs, so leave them alone.
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I have drilled rotors. I haven't machined them with new pads. I've never machined the 928 rotors. I just change them out when they reach the wear limit (30mm, which is 2mm wear, evidenced by a 1mm edge lip on each side).
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
I have drilled rotors. I haven't machined them with new pads. I've never machined the 928 rotors. I just change them out when they reach the wear limit (30mm, which is 2mm wear, evidenced by a 1mm edge lip on each side).