CDLVancouver

ive done a search on this but nothing popped up for the 996...some cayenne stuff though.
in the cayenne forums they write about the rotors lasting 2 pad replacements.
my c2 is at 113k kms. ive done the fronts already and now that im putting the car into winter hibernation i figured that i would eventually get to doing the rear brakes. the rear rotors do have a decent lip on the outer edge of the rotor. i am assuming that with those km's and the lip that the rotors should also be replaced?
do you all also replace the wear sensor and the clips as well, or just re-use?
thanks

Dennis C

I replace the clips and hardware with mine. If the sensors haven't been activated yet and you're changing the pads and rotors proactively, then you can reuse the sensors.

San Rensho

If the brakes don't shudder in a high speed stop, then measure the rotors and if they are within spec, just replace the pads, even if there is a lip or score marks on the rotors.

rpm's S2

The connections in the old sensors can get pinched and broken. I sourced a set of sensors in case mine were toast when they came off. I re-used the old ones and returned the new ones.

I would very carefully consider re-using rotors. Not saying you can't, but its just a couple hundred more dollars. And I would definitely replace them if there was a lip or scoring.

Shark Attack

The tolerance for the rotors is very narrow. I would replace them anyway.

Dennis C

I agree with the comments on replacing the rotors. The Cayenne rotors are huge and quite thick, so it may not be a good comparison.

CDLVancouver

Ya the sensors and clips and such dont add up to much so had already added them into my cart. The new rotors plus shipping is around 450...225 of that is shipping! So im getting a bunch of other goodies thrown in too...a couple of oil filters and plugs and washers, tshirt!, battery tender charger, windshield wipers, new shock for my hood/lid thing, column switch, and pads... total comes out to about 1k all in.

Audi Junkie

Reuse rotors, no probs.

targa996

Its tempting to just change pads on rears .. harbor freight had low cost digital caliper ..easy to measure rotor to see if still in spec .. at a couple of points .. however if scored you need to turn them and then see after turning if they would still be in spec. If tracking the car, don't mess around, replace rotors at every pad change. I successfully reused sensors. If spring clips are not rusted you can probably reuse. Rotor screws are cheap. Caliper bolts are also recomendded changed .. my car has not been tracked and bolts were not corroded so I reused with anti-sieze .... there are a few debates on that ..would probably use new porsche bolts st $6 ea if I did it again ....

rpm's S2

Turning slotted rotors - bad idea. No good shop I know would do it.

spender

I did my own pad and rotor change with Van's helpful video series. In the course of my research leading up to this, I found that the conventional wisdom in the Porsche community was that a set of rotors would typically last for two pad changes - but that would be for daily drivers, not track guys.

Ubermensch

I would ignore any advice that does involve the word "measure". There's a thickness tolerance. If yours are within that tolerance then it's fine to use the rotors (assuming no cracks between the holes).

dotframe

I re-used the sensors but bought new clips. The old clips were pretty brittle. One even broke when I put too much pressure on it.

As far as rotors go, I grabbed this snippet from another post here on rennlist. I make no guarantee that the data is accurate. It helped me in my decision to keep my old rotors on for now. I'm pretty sure this is for a C4S/Turbo though so I guess you'll have to find similar info for your C2.

"Brake disc thickness, new -- front 34 mm, rear 28 mm
Brake disc wear limit -- front 32.0 mm, rear 26.0 mm
Peak-to-valley surface roughness of the brake disc after machining, max. -- 0.006 mm
Thickness tolerance of the brake discs, max. -- 0.02 mm
Lateral runout of the brake disc, max. -- 0.03 mm
Lateral runout of the wheel hub, max. -- 0.03 mm
Lateral runout of the brake disc when installed, max. -- 0.06 mm"

02TX996Cab

New and wear limit data are correct for a C2. Service manual shows that. It is also stamped on the rotors themselves.

My experience: I replaced pads at 50K miles (fronts were probably 80% used, rears more like 50% used...I wanted less dusty/messy pads, plus wanted to do a full inspection of the braking system); mic'd both rotors and they had over 50% of usable life left. Reused the wear sensor wires and clips. Installed new caliper bolts. Car has not been tracked. So while the rule of thumb of replacing rotors every second pad change appears to hold for my car and driving style, I recommend you measure your rotors each time to be sure, rather than guess and maybe be very very sad.