Upgrading to 350mm rotors on my C2S.

https://www.ebay.com/itm/Porsche-997...s/222778581927

I've got the bolts, but struggling to find an appropriate alternative via McMaster / Grainger / otherwise on the 11mm spacers required. Also not willing to pay Girodisc or anyone for special anodized ones.

Has anyone pieced this together? Short of buying round stock and cutting to size yourself

 

I thought there was a member here that made them, maybe not? I have a lathe, I can make these for you if you want, just shoot me dimensions. Pretty sure I have the right aluminum sitting around. I don't want to step on anyone toes if they are making them already though.

 

https://www.ebay.com/itm/Porsche-997...72.m2749.l2649

 

Literally posted that this is not what I wanted - considering they're selling $25 of hardware for $125.

 

Ummm, the bolts are pretty expensive to get the right grade and length, and making the spacers is possible but not really worth the time. When I thought about piecing the kit together myself it was going to be about $85 + time so I ordered it.

If you can get it for $25 good for you. Make sure those bolts are the right ones. They are only holding all 4 calipers on....

 

Grade 12.9 M8 cap screws in the right length from McMaster are $8.45 for a box of 10.

 

I don’t believe the bolts McMaster stocks are the correct pitch.

(edit - never mind, my info is several years old)

 

M8 bolts are def too small. M12x1.5 should be the thread pitch you want. I don't know length.

 

Another option could be a Rennline stainless caliper stud mounting kit where you install a stud into the wheel carrier, then the caliper slides onto the studs and they have stainless nuts that then secure the caliper onto the studs. I bought a set of these to use on the PCCB calipers on my 997, but honestly, PCCBs are so maintenance free that I've never gotten around to installing them over the past 3 or 4 years since I never need to do brake service on that car.

https://www.rennline.com/Brake-Calip.../CS-BCSK/95MM/

If you think the length is what you need, I'd be willing to sell them to you at a little discount from new. That won't address the spacing issue though, but you could probably stack stainless washers or find a solid aluminum spacer the exact thickness you need. You could also visit a local machine shop and they could make you a spacer. When I was doing the PCCB conversion on my Cayenne Turbo S I took the front calipers to a machine shop and had them mill away 15mm of the caliper mounting post length so I could use a radial to axial mounting adapter as I was putting 958 calipers on a 957 Cayenne.and there wasn't enough space to make a proper adapter with the caliper legs the original length.


Original Caliper Mounting Leg Depth

New Caliper Mounting Leg Depth after machine shop work

Here you can see the face of the machined mounting leg

Custom made Radial to Axial mounting Adapter from Epytec in Germany

Had Ti64 make me a set of custom Length Flanged Titanium Mounting Bolts

Caliper mounted to wheel carrier with custom Titanium Caliper Bolts




I showed that caliper depth measurements because I think I still have the pieces that were cut off of them which might work as spacers for you since the difference between the original and machined measurements is about 14.55mm. The Cayenne caliper is larger though and the mounting bolts are M14, so the holes would be larger than the studs or bolts you'd be using to secure the 997 caliper. For a spacer, I'm not sure that matters too much or you could add an M14 to M8 or M10 (whatever the 997 bolt size is) bushing to make up the difference.

On the Rennline / Tarret stainless stud kits I have, the double end threaded studs are 100.75 mm long so you could check to see if that's the length you'd need to secure one end into the wheel carrier, have enough length to pass through the caliper with a 15mm spacer and have enough thread sticking out to properly secure the nut. The advantage to these stud kits are really for track guys that are constantly removing their calipers to swap rotors and pads for track days as you only thread into the soft aluminum wheel carrier once to secure the stud and then all the future off and on is done on the stainless stud. Constantly unthreading and rethreading steel bolts into the aluminum wheel carrier will eventually strip out those hub threads.







If any of this stuff would help you with the project, let me know. Another option would be to get Ti64 to make you custom caliper mounting bolts in the length you need with the flanged top nuts like I did for the Cayenne, Let me know if you want me to look for the leftover pieces from the Cayenne calipers to use as spacers. I'm sure they're in the garage somewhere so may be able to find them.

 

Appreciate the offer Petza - but I think it's more specialized than I need. I think it's hardware that should be around $50 all in to do right. And I think the information should be out in the open for others doing this easy upgrade.

 

Here's the conclusion:

I could have gone with slightly cheaper 80mm mcmaster hardware, but my reading says I need M12x1.5 in 85mm, which is what the Turbo/GT3 use:

https://www.porschemarinparts.com/oe...lt-9a700758500

That's $44 shipped for factory hardware.

Next, the spacers:

So you can find the hardware for this upgrade for about $60 all in.

 

M12 is 12mm, you will only have 1/8" wall on those spacers once you drill them out from 3/8" to 1/2".

 

Made that correction - swapped out to 1" OD, 1/2" ID spacers.

 

Sweet, did you find some?

 

Slightly off the original topic, but I did this upgrade and thoroughly enjoy it on my C4S. I actually paid the Rennlist member the funds as I realize, it took some time for him to do the R&D. Sure, it material cost is cheap, but heck, better than me spending weeks trying to figure out what fits and does not it.