I’m looking at a car that is a CPO at a Porsche dealer. The rear rotors have really noticeable grooves in them. They’ve already given me a discount on the car they won’t change the rotors and they said they’re just fine

What do you guys think of these grooves?
Hopefully, you can zoom in and check them out.

Is it a dealbreaker? I don’t think so. Just thought I would check in as they could want ~ $2400 for a brake job if I take it in after the fact. Right now they’re offering to do them for C$1400 which I don’t know if it’s worth doing. Keep in mind we’re talking Canadian dollars here.

Thanks very much for the quick response (I’m supposed to pick up Up this afternoon)

 

1st car? All rotors get grooves in them.

Have to measure there thickness to see if replacement is needed.

 

Just upgrade to 350 or 380mm rears.

 

When I was actively shopping for 991.2's, I noticed a lot of S's had rotors that appeared to have those grooves/waves in them. Not sure if that is considered normal or not, but there didn't seem to be any vibration in the brakes when I test drove a couple.

You could ask the dealer to measure the rotor thickness. Since it sounds like you're local, just be sure to give it a test drive (if you haven't already) and see if you feel any pulsing or vibration under braking. If you don't feel that, I wouldn't worry about it. Like I said, this seems to be a 'normal' wear pattern for 991 S brakes.

 

I like how you think! I’m pretty sure I saw a set of 350’s Suncoast parts for a really good price. They were slotted but they looked good.

 

I went through exactly the same thing with a CPO. The dealer said that they were fine - and there were no braking problems at all. It just didn't look good.
I did a complete pad/rotor replacement and the new ones are starting to do the same thing. It seems to be normal for these brakes. You can see similar wear patterns
in random photos on the web.

 

Normal wear for rotors. If you are a DYI'er, they are easy to switch out....when it comes time!

 

Totally normal, if thickness is good.

 

2018 C2S 56,000 miles. I’ve got the grooves in my rotors.

 

My ‘17 C2S has the grooves on the rears with 45K miles. Stops fine, accelerometer shows I did a 1.13g stop the other day when an animal ran out in front of me on a back road. Oddly enough, first owner had the front rotors/pads replaced at 29K miles.

 

Grooves normal wear. Spider cracks at the drill holes are an indication to replace.

 

Doing a little bit of searching, it seems the holes cut tiny bits of pad off, and they get dragged around creating the grooves. I tried some fairly high speed deacceleration runs from 200kph or 220 down to 100 and I noticed a bit of shaking, but it more appeared to be coming from the front and the back. Hard to tell as I was hanging on for dear life - but this was strictly off-road, of course!

 

Porsche in their workshop manuals make clear statements about cracks and grooves in drilled brake rotors:
1. cracks around the drilled holes should not grow longer than to 5 mm ( 0.2 ").
2. No cracks are permissible at the outer perimeter of the rotor.
3. The grooves are not , as was assumed by Renn Rite, deepest at the holes, but at the outer- and innermost perimeter of the contact area of the brake pads, where the pads do not run over holes. There the thickness of the rotor is to be measured.
BTW: you will find the wear limit of the thickness stamped on the rotors.

I have a 991.1 GTS with ca. 50.000 kms ( 31.000 mls.) And yes, there are visible grooves on all rotors. The pads look as if good for another 50.000 kms., same the rotors.
Absolutely normal wear.

 

Thanks for posting this as I was looking for it in the $4100 brake job quote thread.

Here's how it works for the newbies:
.

• Grooves like this on a car you are buying from a dealer? Absolutely normal, nothing to worry about
• Grooves like this when you bring it to a dealer for a brake job? All four rotors must be replaced immediately for a Porsche parts MSRP of $1966

The most important thing to remember is that the dealership sales and service writer are both commissioned salesman. Nothing that either of them tells you can be taken at face value. The salesman is likely right in this case but he'd probably be telling you the opposite if you brought it to him for a brake job.

You can buy all four OE rotors, the exact same manufacturer parts on your car except not in a Porsche box, for $584 from FCP Euro. Replacing them is simple. So no it's not a dealbreaker, even if they did need replacement. But they don't, they are almost certainly fine.

But if concerned, thickness can be checked with calipers, and runout can be checked with a dial indicator. Both can be found on Amazon for under $30 each if needed. Also see the $4100 brake job thread as I posted links to the rotors from FCP Euro in the comments.

Edit: Here's the comment with links to the OE rotors from FCP Euro. You don't need new ones, but this shows that even if you did it's not a big expense.

https://rennlist.com/forums/991/1508...l#post20520995

 

This is great information thank you very much for all of this detail. What a coincidence we’ve both gotten 991’s with the same mileage - they’re sweet cars, aren’t they?

I bought the car drove it 550 km home and was giggling and laughing much of the way. WHAT A MACHINE!!!! ❤️