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

[Casa de Mesa]

Got it. This makes more sense now.

I enjoy the root cause analysis part sometimes more than the actual solution.

[Obioban]

I guess where I'm coming from... If it seized suddenly (which it appeared to), that seems suspect. I feel like a sticking piston due to dirt or corrosion should have revealed itself long before via other tell tale signs (car felt down on power, smelling the stuck pad on the drive to the track, a dusty wheel when all others were clean, a scorched rotor). Would be interested to see if the pad is severely worn on one end, especially compared to the same same caliper on other side of the car.

What I'm curious about is the suddenly frozen part.

And I'm still in for the solution!

So, it was worn out more (~double the wear of the other side).

The previous lap he thought he maybe smelled hot brakes, but they felt fine and the smell went away so he assumed it to be someone else's car.

The session before he noticed the car was pulling to the right under braking.

So, it wasn't exactly spontaneous-- but it did suddenly not have braking (probably faded on that side) on the lap in the video.

[Casa de Mesa]

He hasn't pulled them apart yet to inspect, but that seems like the most likely culprit to me.

I guess where I'm coming from... If it seized suddenly (which it appeared to), that seems suspect. I feel like a sticking piston due to dirt or corrosion should have revealed itself long before via other tell tale signs (car felt down on power, smelling the stuck pad on the drive to the track, a dusty wheel when all others were clean, a scorched rotor). Would be interested to see if the pad is severely worn on one end, especially compared to the same same caliper on other side of the car.

What I'm curious about is the suddenly frozen part.

And I'm still in for the solution!

[Obioban]

First, glad he and the car are ok.

Second, did it seize because of debris for sure? Seems unlikely... but maybe not.

To be clear, I'm in for the solution despite my prior post.

He hasn't pulled them apart yet to inspect, but that seems like the most likely culprit to me.

[Casa de Mesa]

First, glad he and the car are ok.

Second, did it seize because of debris for sure? Seems unlikely... but maybe not.

To be clear, I'm in for the solution despite my prior post.

[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.

[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.

[Tbonem3]

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

[Sergmann]

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

[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.

[Obioban]

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

[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? 😛

[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

[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.

[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.