MaxLTV

So my pucks chipped to the level I'm no longer comfortable with, and I want to take care of that as Porsche would not do it for me.

By the way, I know for a fact that pucks do not crack from running pads too thin. My pads in one caliper disintegrated at a track and I kept running for some time, because it did not feel too bad, and pucks in that caliper did not crack. But my pucks did crack in the other caliper earlier when I ran with tapered pads. Anyway, that's beside the point.

I'm trying to understand what's the best replacement option - just pucks or entire pistons. (here are the links - Pistons: http://www.racingbrake.com/12ea-SS-P...-p/bp-608p.htm and Pucks: http://www.autoquestcars.com/custom-08 )

Both options require removal of pistons, so labor should be the same.

In terms of heat conductivity, it's hard to say but steel seems to win. Its heat conductivity coefficient is very similar to titanium BUT steel pistons can have much thinner walls while being stronger. Total heat transferred is Transfer coefficient * Cross-section area, and the latter is much smaller for the steel version. Also, this set up gets rid of the OEM aluminum piston, which is very conductive (>10x conductivity of steel, given that's it's also much thicker).

In terms of longevity, steel also seems a better option, because it's a one-piece design, so no bolts, loctite etc involved.

What worries me is how that plays with the caliper - steel and aluminium have different heat expansion ratios with aluminium expanding 35%-50% more than stainless steel. But the piston will be hotter than the caliper, so smaller expansion ratio for pistons may actually be a benefit. Anyway, I'm not sure.

Lastly, is there anything I'm not thinking about? (please don't say resale )

tstafford

Subscribing to thread.

Question for OP: How many track miles do you have on the car such that this has happened? Seems like a wear item so I'm wondering when I should budget for this one.

MaxLTV

My front pucks started cracking and chipping on the first set of oem pads back in 2014. I switched to a different pad brand and the chippping slowed down. Then one caliper was replaced because of unrelated damage, and two years later it's still fine, but the original one is chipped badly. Total 20K miles, ~30 track days, but more than half of damage happened within the first 2k miles on oem pads that tapered badly. That's why I think it's related to pads and/or tapering. Rear is ok.

qbix

Intersted as well but I think that ceramic pucks are there for a reason. If that was that simple why Brembo with I imagine huge experience would not just make one piece steel pistons which would be more cost effective for them?
I don't know how hot the steel pistons would get but treated with high temps over time might change their properties drastically and lead to a maybe catastrophic failure?
If thermal conductivity is same as titanium I would go for titanium just for that single reason.
In my opinion the best solution would be to get ceramic pucks and treat those parts as consumables.

Spyerx

If they replaced caliper has been fine I’d just replace the caliper. By time you get into removing and disassembly labor plus parts how d
fsr off are you in price? Oh and I’d not buy anything from rb. That’s just me.
Brembo uses steel and ti on its factory racing calipers.

RobT 394

Realize this is the 991 forum and my 997 experience may not apply. The pucks crack due to heat. The nannies on the car cause excess heat. On 997 the rear is constantly at work if you drive with nannies on. Pucks crack. Could be same on 991 or could be all 4 corners work harder.

Replacing the brembo pistons and pucks is not hard just time consuming and a little messy. For my money I would go back with brembo OEM parts. FVD used to sell them if you are DIY person. They are not cheap.

Easiest solution is pull calipers and send to John Hayworth at Hayworth Racing Brakes. Believe the company and website is this: http://prosystembrakes.com/

MaxLTV

OEM pucks are not available , and replacing them with aftermarket pucks is just as messy as replacing pistons because it requires taking calipers off and pistons out.

The new caliper shows no cracking so far, but other cars with same-locking newer calipers had cracking, so I do not expect it to hold up too long. Treating the entire caliper as consumable is probably not justified.

GT3ZZZ

Here you go:

https://rennlist.com/forums/991-turb...-ceramics.html

Spyerx

Calipers are consumables.

MaxLTV

Why? If only a small part of it breaks, why not replace just that part? I'd argue that entire GT3s are consumables too, and no person should be driving one that's more than 2-3 years old, but with how much fuss it is to buy a new one, replacing some wear items on old timed out cars seems worth it.

Yargk

Perhaps over long enough time scales, but I think there's a lot of useful caliper life left after just the pucks crack!

Spyerx

They are wear components. Critical ones at that. At some point it’s nit about the pucks but piston bores that are wearing or metal fatiguing. Just like hubs bearings suspension components etc.

ed of the day did you price out a caliper vs the parts and a rebuild? On the 997 they aren’t that different and you can get rebuild kits. cup racers mostly just replace the calipers as a result.

Yargk

Agreed, but if the pucks fail after 20 track days and caliper cost and installation is 4k, then if you replace the caliper at the puck failure time you're paying $200 a track day for calipers. Seems like entirely new calipers should be a 50+ day replace item item. (on the 991/981 cars, I'm guessing it's 1.5-2k parts and labor to go with titanium pucks from AutoQuest and 1-1.5k if you go with the SS RacingBrake pistons)

TRAKCAR

My RS just spent its 3rd week at the dealer for its 24,000 total and 12,000 track miles service intervals. Also have a few cracked pucks affecting one front and one rear caliper. The solution is under review.

Anyone have the caliper replacement cost?

MaxLTV

Yeah, but it's probably a much longer time frame than replacing pucks. I know of many calipers with 5+ times as many track days on them as I have on mine without calipers failing. I saw wheels, hubs, suspension arms and bushings and other parts failing far more than calipers cracking due to metal fatigue. They almost don't flex compared to the rest of the car, so fatigue should be much smaller.

Replacing calipers is $5K+, re-building is ~$850 with pucks replaced and about half that without replacing from what I've heard so far. So a compelling proposition, especially taking into account that replaced calipers will crack just the same as old ones in few months.