Porsche Brembo 996 BBK Conversion-- let's figure out how to fix the dust boots/seals

[Obioban]

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/229329-porsche-brembo-996-bbk-conversion-let-s-figure-out-how-to-fix-the-dust-boots-seals?p=238109#post238109

Let's start off with the issue: The factory 996 seals don't seem to be able to take the heat of tracking. These were <500 mile old OE Porsche:



This seems to be a fairly known issue in the Porsche community (probably worse for us, with our heavier and more powerful cars):
https://rennlist.com/forums/parts-ma...ure-seals.html

However, their solution is NLA with stoptech shitting the bed:
https://www.ohioperformancesolutions...-rebuild-parts

Stoptech shitting the bed, I say? Yes:

StopTech is broken and these rebuild kits have been difficult to keep in stock. The acquisition of StopTech (and Centric Parts) by First Brands Group was a total disaster. First thing the new owners did was cancel all open orders with existing suppliers and shift production orders to their own factories. No matter that they didn't have the tooling or the experience. So the rebuild kits quickly went on backorder and certain sizes have been unavailable for nearly a year.

Reach out to Pat McCleish <autobrakesolutions(at)gmail(dot)com>. He's a former brake systems engineer at Centric who left shortly after the acquisition. Now he has his own caliper rebuild parts company and he works with the former manufacturers for StopTech and Centric. So he can get you everything you need. Plus he's got extensive expertise on Porsche, exotic, and antique calipers. He's your guy!

That seems relatively self solving-- reach out to Pat and get what used to be OE Stopetech seals.

The reason I'm not quite satisfied with that answer is that stoptech boots/seals were never amazing-- most people I know with stoptech brakes, that are reasonably quick on track, replace their seals every 1-3 years. Brembo seals are good for a decade+.

So, what I'm really looking for is a good way to buy OE brembo BBK seals in 996 caliper sizing, front and rear. Pat seems like a reasonable fallback (1-3 years is certain better than the OE Porsche good for <1 day on track at speed).

The OE Porsche seals are made by brembo, but, given how they (fail to) hold up to the heat of tracking, they must be using a different material than Brembo does in their BBKs.

So, I suppose 3 questions:
1) Does the 996 caliper have the same size piston:bore ratio as other brembo calipers, so the brembo BBK seals would plug and play in?
2) Does anyone know where Brembo BBK grade replacement boots/seals can be purchased?
3) ... what size boots/seals does we even need? Best I can find is "28/32/38mm Brake Caliper Rebuild Kit Porsche 996/997 GT3"
Does that means those are the sizes for 996 GT3? Or 996s and 997 GT3?

... I have an email in to Pat, to see if he can source Brembo seals. Will update this thread if he can.

[repoman89]

Just going to say that I’ve had good luck with the Girodisc dust boots. I only have a couple years and maybe 10 track days and 3000 miles on them but that’s better than OE Porsche apparently. Rotor temps typically around 600-650 F in the paddock after a cool down lap.

[bmwfnatic]

I found several websites selling blue colored seals, supposedly made from a Silicone high temperature material.

https://racingbrake.com/bp-404bs/

On this website you can nicely navigate by make and model and caliper part number.

I have no experience with this website or boot style, maybe someone else does, just putting it up for debate.

[elbert]

I've also used GiroDisc boots and seals, and have good results so far. Granted, this is for rear calipers only, which aren't getting quite as hot as my front brakes.

I bought some Brembo seals and boots (for my front Stoptechs) from Hoerr Racing (hrpworld), as Girodisc was out of stock at the time.
They respond fairly quickly to emails and might be able to help you about the Porsche calipers.
Apexperformance.net also sells a lot of Porsche stuff and might help as well.

For the rear calipers, sizes are 28 and 30 mm. Can't help regarding the fronts.

[repoman89]

Fronts are 36 and 40mm

[Obioban]

Update.

Pat says,

Hi Ian..

I don't sell any brembo OE parts, I only have aftermarket replacement components. I have boots in both black EPDM rubber as well as grey silicone (high temp). As you know, under track conditions, all bets are off as far as making guarantees regarding the lifespan of the anything. All we can do is try and see what happens. Titanium heat shield shims may also be a decent idea, and certainly can't hurt.

We have kits and pistons available for both your front and rear calipers. Front kit is part number K3713 (put an "S" at the end for silicone boots) and the rear kit is part number K3709 (S at the end for silicone).

They can be found at autobrakesolutions.com

Let me know if you have any other questions.

[Tbonem3]

Grey stop tech are condom thin. I think I've seen dark blue brembo hi-temp boots before.

You don't have to use boots. Or, use the factory brembo and let them degrade, they're just keeping debris out.

Then rebuild inner seals annually or 2 yrs.

[heinzboehmer]

Was just talking to some local people about heat management with these calipers the other day. The stock noise isolators that stick to the pads are made of what appears to be steel with a rubber coating. Bry5on ran the math and found that a heat shield made of 0.1mm elastomer and 1mm steel would result in the same thermal conductivity as 1mm of titanium. Any thicker on the elastomer and it outperforms Ti.

Point of this is that the calipers are designed to have those isolators installed. Heat getting to the dust boots is probably much higher without them. The problem is likely extra bad with track pads, as most of them have a backing plate made of just steel and lack that HDPE-like layer that street pads like textars have on them. I know that layer is probably mostly on there for noise, but it should make a pretty big difference regarding heat transfer as well.

My plan is to use the OE Porsche/Brembo dust boots and a heat shield. Haven't decided yet if I want to run the titanium shims or the stock Porsche ones with the metal cylinders removed (pic below). Will likely buy the Ti stuff and run a quick experiment to see which one does a better job at track temps.



I know this didn't answer your question, but I figured I'd share, as less heat there should help prolong the life of the seals.

These are the appropriate dust boots:

- https://www.fcpeuro.com/products/por...or-95135191700
- https://www.fcpeuro.com/products/por...or-95135191701
- https://www.fcpeuro.com/products/por...or-95135291700
- https://www.fcpeuro.com/products/por...or-95135291701

[Obioban]

Grey stop tech are condom thin. I think I've seen dark blue brembo hi-temp boots before.

You don't have to use boots. Or, use the factory brembo and let them degrade, they're just keeping debris out.

Then rebuild inner seals annually or 2 yrs.

I don't know about you, but I don't feel like rebuilding my brakes every 2 years. Also, why 1-2 years, if they fail in one day? 😛

[Obioban]

https://www.zeckhausen.com/catalog/index.php?cPath=82_1169_1170

[Casa de Mesa]

Have you thought about not running seals?

From here:

https://www.essexparts.com/ap-racing-by-essex-radi-cal-competition-brake-kit-front-9669355mm-porsche-9971-base-986987-boxster-cayman62446246

...click on the FAQ section.

I know this is for AP brakes, not the Porsche/Brembo, but including for discussion purposes.

Q: Do your kits require more maintenance than other big brake kits on the market, due to the lack of dust boots, anodized caliper finish, etc.?

A: Absolutely not.We are perpetually shocked by this question, because it makes no intuitive sense.If you have a product that is specifically designed to handle the extraordinary high-heat conditions of track use, why would it require more maintenance when used under those conditions vs. brake components that were designed to cruise around on the streets at low speed? When using your brakes on the track, dust boots are pointless.We've seen many people burn them up in a single session. Once that happens, you're just driving around with some tattered, burnt rubber bits attached to your pistons. We skip making that mess for you.

[Sergmann]

I simply don't run them on my track car. Its been three seasons so far with no issues.

[Tbonem3]

That's what I was saying. People think they're a critical part like the inner seal.

[Obioban]

If it's a track only car, sure, no seals and frequent rebuilds may be fine.

... but if it's also a DD, that quickly isn't tenable.

I ran the same dust seals (whatever they came with stock) on my Brembo GTs for 13 years/20,000 track miles, and never had them fail. So, this isn't an unobtainable goal.

[Obioban]

Calipers seizing up from crap in them is no joke-- this really took center stage for me at this moment because a friend of mine had a front 996 caliper seize up on him last weekend on track, at ~130mph:

Could have gone worse

... I'd still like to keep crap out of mine, which means dust seals.