atb

Have big reds on my car and was just curious if the Porsche cast in hole rotors I have can be turned or if the only option is to have them replaced.

Just curious. I have a track day coming up and was thinking of doing a quick turn if possible, there are some ridges appearing.

69gaugeman

I don't think ridges or grooves are going to be an issue as long as the thinest point is larger than the min thickness for the rotor.

I don't have any racing brakes experience but a lot of passenger car brake experience.

69gaugeman

I wouldn't turn the rotors unless it is pulsating. Are you intending to change the pads?

RyanPerrella

i think you want to have them turned just to have them resurfaced if nothing more.

Ive always wondered this as well, would love to know.

AO

I don't beleive they can be turned in the traditional sense. They need to be ground, but I don't know of too many places that do surface grind turning (at a reasonable price).

Jack Riffle

Yes, they can be turned but it is not cheap. My front 996 rotors and rear s-4 cross drilled rotors cost me $110 to have turned. It requires a special machine and also all of the holes must be re-chamfered and cleaned out. Oh yeah.....and they can only be turned one time.

Daniel Dudley

Fluid change might be more in order if you haven't done it for a while. Hot brakes and moisture in the fluid can lead to rapid brake fade, odd lockups or even pedal to the floor situations. Not fun.

RyanPerrella

why bother to turn them if they are that much work.

If i go to larger brakes i will be using 993 TT rotors on 965 aluminum hats. The rotors alone cost a whopping $172.50 each, Thats so damn cheap, i would never think of having them turned.

Good to know they are turned but it would seem to be a labor intensive process. was 110 for all four or what?

Last time i had rotors turned it cost about $20 each but think the going rate is anywhere from $10-$20 per corner.

Jack Riffle

It was $110j ust for the two front rotors, and believe me, 996 rotors are not cheap. The really tricky part is finding a shop that has the proper equipment. You aren't going to get this done at your local NAPA store.

pearlpower

I have personally turned well over a thousand rotors in my last profession, many were cross drilled and slotted including my own personal iron. I also owned my own lathe at one time and now that I have a larger garage am looking to pickup another one. They turn the same exact way as a normal rotor would. Why would it not?

Nothing more to do vs a regular rotor. No harmonic issues, no issues with the bits. Some places are cautious turning them as they have no experience and shy away. I go through rotors often in my cars (hard canyon drive almost everyday and drive 200+ miles a day). Never an issue.

morganabowen

Thank you, that is the response I wanted to see

Jack Riffle

Not really sure why they are different, but I do know I went to five different places who all said they didn'y have the proper machine to turn them with before being reffered to a shop that did. Don't kill the messenger.

the flyin' scotsman

Jack ............the diff is perhaps doing the project oneself with the skills and machines vs. approaching a shop asking to turn "Porsche" brake rotors.

I'm amazed sometimes when true mechanics still shy away when you mention your car is a Porsche.........its just a car!!!!

Personal experience: I had my OEM front rotors turned by a 30yr exp. GM mechanic.............he said he'd never seen rotors so hard

RyanPerrella

HONESTLY, is there really any skill required to operate a brake turning machine? Seriously, no disrespect here.

Ive seen it, the guy measures the thickness, mounts the rotor in the machining, sets the depth of the cutting tool and it rotates. Then repeats on the other side of the disc. Pretty simple to me.

I see thats there would be issues with refinishing the holes throughout the disc because if you didnt you could potentially eat through pads in no time, how thats done wether by hand file or with an electric drill with some type of bit or what is beyond me.

Glad to know its possible.

pearlpower

Actually anyone can be trained to drive a car; it takes training to drive one properly. Same goes for anything including turning rotors. Properly mounting a rotor using the most compatible adapters and able to READ a rotor while it is turning takes a bit of experience. Just slapping on a rotor and hitting ON does not do it though many rotors get turned that way.

The holes on cross drilled rotors holes should be chamfered to begin with and turning the rotor will eat away a little at that but if it gets to the point of eliminating the chamfer altogether then the rotor is most likely too far gone.