nels415

Is trying to resurface rotors a bad idea? They only have about 30k on them, but appear to have a significant amount of grooving. I don't seem to be warped at all. If I was to get them resurfaced and replace new brake pads (oem textars), should they be alright to use. Or is resurfacing a rotor for a 993 a no no?

whoops, meant to post this in the 993 forum. but still pertains to you guys since i have a c4s.

-nels

ca993twin

I may be a minority opinion here, but I'd rather have grooves in my rotor than take material off the rotor. Brakes pads will quickly (if bedded correctly) conform to the grooves, and there should be no downside. When you get a nasty lip on the edge of the rotor, or suspect it is warped, toss it. One man's opinion.

ScottMellor

Hmm. I agree with Steve. Alert Ripleys.
Rotors are heat sinks. Less material means less heat sink. I also replace my pads when they get to less than 50% for that reason.
I replace my rotors when the inter-hole cracks get out of spec.
My brakes always work at the track.
(Yes I know I don't go too fast but that's beside the point!)

enthusiast

I agree, don't machine them period! The grooves are normal.

chris walrod

if you install new pads on grooved rotors, you may want to go easy on bedding them in. This is because the new, flat pads will ride only on the high portions of rotor (until fully bedded that is) causing local areas of the rotor to superheat. This localized heating can cause hard spots and possibly warping. Of coarse this is only until the new pad is worn into the contour of the rotor.

nels415

okay, so I guess the consensus is to not resurface them, but rather buy new rotors or just go ahead and bed in new pads carefully.

993_996 enthusiast, you say grooves are normal, but is there an amount that would be considered abnormal?

thanks for the feedback guys.

-nels

hatchy

Not a lot of people can resurface drilled rotors, so if you do decide to do it, make sure you take it to a good shop.

enthusiast

nels415, I haven't heard of or use any scientific measurement on the grooves. Most of us, for street or track use, go by the feel of the brakes. For instance, in track use one can get a temporary build up of brake pad material on the disk surface. That condition has a 'feel' to it when one applies the brakes. Through the normal braking process the build up wears off and the brakes feel and perform normal again.

chris walrod's point above is right on about bedding any pads new or used to a worn disk.

Carrera GT

I'd vote for new rotors. If you want to machine the rotors and stay in spec for thickness, no biggee. I think the performance and heat dissipation will still be -- with big reds -- more than ample for street driving in a naturally aspirated car. For track days, I wouldn't go on the track with machined rotors or anything less than 70% pads and a very firm pedal feel.

Unfortunately, factory prices on rotors has skyrocketed in the last six months.

I recently went to cryo rotors on the front and I'm very pleased with the results. I'd also suggest going to the trouble of using street pads and track pads to extend the life of the rotors. Still, like tyres, wheels and suspension, the brakes are a wear item.

mooty

i won't resurface rotors on porsche, especially cross drilled one.

wow, adam, we are at opposite ends. you repalce pads when it's less than 70%, i replace them when i am at the backing plate ;o) just kidding, but i did run of pad two fridays ago at TH. had to pack up early.