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Hi all,

My rear rotors have about 10mm left on them. I believe the manual says at least 9mm minimum needed to be resurfaced. Am I just waisting my time here or do you guys think 10mm is enough meat for them to last a while? Would you replace? Just trying to save a couple of bucks.
 

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I believe 1mm is equal to about .040", which is a lot in terms of surfacing unless they're really trashed. I wouldn't surface them just because of slight grooving, only if it's really bad, or if they're out of plane enough to cause the pedal to pulse. I think there's way more surfacing/replacing of rotors than strictly necessary form a performance point of view.
Andrew
 

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Rear rotors on a transaxle car are not something to be lightly considered for removal. It's a big job.
Andrew
 

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I've not resurfaced a rotor on several cars for over 30 years. I replace pads while they have some good material remaining so the discs never get scored, and put now rotors on every third (fronts) or fourth (rears) pad change. Worked on Big 2 ton MBZ 560 SEC, 3 and 7 series BMWs, and three Alfas. (Except for the latest 325Ci, these all had the same ATE brakes of different sizes. I got so good at it that the 30 minutes to R&R all four tires took longer than replacing all four pads.)

Just stay away from those rock hard metallic racing pads. If the discs are warped (pulsing), it's from overheating late in the disc life (getting near too thin), and should be replaced anyway. Just don't let the pads get too low!

If you use slotted/drilled rotors, the pads will wear a LOT faster, especially if they are street class pads. Slotted/drilled are NOT needed except for AX/TT/Track day cars, which would also be using harder pads at least for the competition days.

You really should avoid using racing brake set-ups for street driving. Cold and hard pads take longer to stop for normal driving.

The one issue I have with not resurfacing is eventually you get a thick rim on the outer edge of the disc, where the pad does not contact. Makes installing the next pad set hard, at least. I usually just futz with it, but occasionally I've ground it off with a disc grinder, ignoring the tiny balance issues.

Practical Mechanics 101.

Robert
 

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Rear rotors on a transaxle car are not something to be lightly considered for removal. It's a big job.
Andrew
Breaking loose the bolts that retain the rotors is the tricky part. There isn't enoungh clearance for a socket and a 12-point wrench is likely to round the shoulders off the bolts. My Alfetta is long gone, but Dave Vegher advised me to purchase a 6-point socket from Snap-On and grind it down to about 1/2 the original height. Worked like a charm.

Mike R
 
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