How often is everyone rebuilding calipers?

[dparm]

Is there a recommended schedule or rule-of-thumb for when you should rebuild a caliper on a car that's getting track time? I know that track days will break down the seals and other components much more quickly than normal street driving.

Rebuild kits from Centric are only about $25-35 per caliper:
Caliper rebuild kit - front (30/34/38mm pistons) consisting of 2 of each size dust boot and pressure seal to rebuild one 6-piston caliper


My Corvette has seen 8 or 9 track days in its first year. Just debating if this is something I want to get done at the start of every season, or if that's being way too anal and these things are built to take abuse. If it helps, the car has the big Brembo 6-piston front and 4-piston rears.

[dbyrd]

I just rebuilt my Stoptech Trophy ST-60 front kit after they blew a seal after about 2 years - approximately 30-35 track days. I'll probably rebuild them every 25 track days or so going forward.

[dparm]

Originally Posted by dbyrd

I just rebuilt my Stoptech Trophy ST-60 front kit after they blew a seal after about 2 years - approximately 30-35 track days. I'll probably rebuild them every 25 track days or so going forward.

Do you run your pads down pretty far? Any shims?

I talked to Dave Zeckhausen and he said that's a huge factor -- the heat transferred to the calipers rises greatly once the pads get past 50% worn.

[dbyrd]

I run my pads to about the width of the backing plate. No shims. I have 2.5 inch cooling ducts which make a huge difference. I'm running Cobalt Friction XR1s or XR2s, and they last about 6 track days in front. Back lasts 3 or 4 X longer.

I sourced the rebuilt kit from Dave, and I spoke to him several times. What a cool, knowledgeable guy - I don't know how he makes the time to talk to us car geeks. At his suggestion, I bought the Assembly Fluid for caliper rebuilds. This coats the seals for easy installation - https://www.zeckhausen.com/catalog/p...ducts_id=15352

[dparm]

Originally Posted by dbyrd

I run my pads to about the width of the backing plate. No shims. I have 2.5 inch cooling ducts which make a huge difference. I'm running Cobalt Friction XR1s or XR2s, and they last about 6 track days in front. Back lasts 3 or 4 X longer.

I sourced the rebuilt kit from Dave, and I spoke to him several times. What a cool, knowledgeable guy - I don't know how he makes the time to talk to us car geeks. At his suggestion, I bought the Assembly Fluid for caliper rebuilds. This coats the seals for easy installation - https://www.zeckhausen.com/catalog/p...ducts_id=15352

Cool, thanks. Yeah, Dave knows his shit and I've talked to him tons of times. I think his wife even tracks her Corvette. :-)

My car has dedicated cooling ducts and I run Hawk DTC-60s with SRF. The OEM 2-piece rotors are beefy and have the J-hooks.

[XCUSE_M3]

Anyone rebuild there ap racing kit? Have not heard or seen anyone do them. Mine are coming up on 2 years old.

[dogbone]

Originally Posted by XCUSE_M3

Anyone rebuild there ap racing kit? Have not heard or seen anyone do them. Mine are coming up on 2 years old.

I have had my AP kit almost 6 years. I have found that if you track around 20 times per year, the seals start failing around 18 months.

I always sent my Stillen AP calipers to Stillen for rebuilds, and I plan on sending my Essex AP calipers to Essex for rebuilds. At the moment, I don’t feel like I have the knowledge or equipment to do it properly. For instance, I can’t pressure test the caliper.

[Redd]

What are the symptoms when your calipers need to be rebuilt?

[SYT_Shadow]

I'm getting my PFC kit rebuilt after just over 100 track days

I don't run ducting. They never leaked, but eventually the coating on the pistons started flaking off so I thought I might as well get it done during winter.

I have no intention on ever rebuilding these things myself. When I send them back to PFC I get every bolt/nut replaced and the whole thing measured in a CMM machine to see whether my cretinous braking habits have caused damage.

[dogbone]

Originally Posted by Redd

What are the symptoms when your calipers need to be rebuilt?

This topic is fairly frustrating for me because I asked many people, including Stillen, what the service interval should be. No one could give me an answer. I ended up having to create my own service interval. I don't know if it's frequent enough. I'm 100% sure it's not too frequent.

Here are three things I've observed over the years as the seals age and need replacement:

1. On a Stillen front AP kit, the seals are internal. When everything is fresh, you cannot see any seals. As the seals age, you can see the seals poking out around the pistons.
2. You can see brake pad dust around the pistons is "hanging out" more than it should and has a darkish "moist" look, meaning that brake fluid is seeping out around the pistons and is capturing brake pad dust.
3. You can see the dried remains of a mysterious fluid on the inside of the wheel barrel, but you can't observe any leaks when the car is at rest.

If you see any of these signs, I'd say it's time. If you see #3 in particular, I'd say you're past due. #3 means that under the high pressure of hard braking, the caliper is spewing enough fluid to leak all the way onto the wheel.....

It's hard to see the state of the internal seals of the Stillen AP rear kit because there are dust boots covering them. It's typical for the dust boots on the rear to look completely cracked and destroyed. But that's not necessarily a sign of needing service. Those "high temp" dust boots get destroyed after one day on track. So, for the rear, you are searching for moist-looking brake pad dust hanging out inside the caliper near the pistons.

In my experience with BBKs, the aging process is gradual. You get signs before an outright failure occurs. But the user needs to be looking for them. I think putting these three things on your radar is a good place to start.

(I just saw SYT_Shadow saying he got 100+ days. That would NOT be possible with my Stillen kit. The first time I sent the kit to Stillen for rebuild, they said it was DEFINITELY time.....even past the time.....and that was less than 40 track days.)

[Atomicteal_M3]

Originally Posted by dparm

Cool, thanks. Yeah, Dave knows his shit and I've talked to him tons of times. I think his wife even tracks her Corvette. :-)

My car has dedicated cooling ducts and I run Hawk DTC-60s with SRF. The OEM 2-piece rotors are beefy and have the J-hooks.

I can't really comment on caliper rebuild however I can say that Dave is awesome! I just ordered replacement rotors and new bridge bolts for my ST40 kit this morning and I already have a tracking number! When I ever decide to rebuild my kit, I'll be ordering from him that's for sure!!

[Redd]

Thanks dogbone! Let me check mine out.

[dparm]

Originally Posted by dogbone

This topic is fairly frustrating for me because I asked many people, including Stillen, what the service interval should be. No one could give me an answer. I ended up having to create my own service interval. I don't know if it's frequent enough. I'm 100% sure it's not too frequent.

Yes, various Google searches and chatting with other track day guys has basically produced the same answer: "they need a rebuild when they need a rebuild."

I guess it's just not very black-and-white. There are too many variables so you just have to pick an interval that airs on the safe side.

[dparm]

Originally Posted by BLKLYZ

I can't really comment on caliper rebuild however I can say that Dave is awesome! I just ordered replacement rotors and new bridge bolts for my ST40 kit this morning and I already have a tracking number! When I ever decide to rebuild my kit, I'll be ordering from him that's for sure!!

His prices are not rock-bottom, but I am fine spending a few extra bucks for the excellent customer service and the peace-of-mind knowing that I can call him anytime with questions.

Have been ordering from him for 8 years now.

[roastbeef]

Originally Posted by dogbone

This topic is fairly frustrating for me because I asked many people, including Stillen, what the service interval should be. No one could give me an answer. I ended up having to create my own service interval. I don't know if it's frequent enough. I'm 100% sure it's not too frequent.

Here are three things I've observed over the years as the seals age and need replacement:

1. On a Stillen front AP kit, the seals are internal. When everything is fresh, you cannot see any seals. As the seals age, you can see the seals poking out around the pistons.
2. You can see brake pad dust around the pistons is "hanging out" more than it should and has a darkish "moist" look, meaning that brake fluid is seeping out around the pistons and is capturing brake pad dust.
3. You can see the dried remains of a mysterious fluid on the inside of the wheel barrel, but you can't observe any leaks when the car is at rest.

If you see any of these signs, I'd say it's time. If you see #3 in particular, I'd say you're past due. #3 means that under the high pressure of hard braking, the caliper is spewing enough fluid to leak all the way onto the wheel.....

It's hard to see the state of the internal seals of the Stillen AP rear kit because there are dust boots covering them. It's typical for the dust boots on the rear to look completely cracked and destroyed. But that's not necessarily a sign of needing service. Those "high temp" dust boots get destroyed after one day on track. So, for the rear, you are searching for moist-looking brake pad dust hanging out inside the caliper near the pistons.

In my experience with BBKs, the aging process is gradual. You get signs before an outright failure occurs. But the user needs to be looking for them. I think putting these three things on your radar is a good place to start.

(I just saw SYT_Shadow saying he got 100+ days. That would NOT be possible with my Stillen kit. The first time I sent the kit to Stillen for rebuild, they said it was DEFINITELY time.....even past the time.....and that was less than 40 track days.)

This is gold. Thank you.

[dozaiya]

Originally Posted by dogbone

This topic is fairly frustrating for me because I asked many people, including Stillen, what the service interval should be. No one could give me an answer. I ended up having to create my own service interval. I don't know if it's frequent enough. I'm 100% sure it's not too frequent.

Here are three things I've observed over the years as the seals age and need replacement:

1. On a Stillen front AP kit, the seals are internal. When everything is fresh, you cannot see any seals. As the seals age, you can see the seals poking out around the pistons.
2. You can see brake pad dust around the pistons is "hanging out" more than it should and has a darkish "moist" look, meaning that brake fluid is seeping out around the pistons and is capturing brake pad dust.
3. You can see the dried remains of a mysterious fluid on the inside of the wheel barrel, but you can't observe any leaks when the car is at rest.

If you see any of these signs, I'd say it's time. If you see #3 in particular, I'd say you're past due. #3 means that under the high pressure of hard braking, the caliper is spewing enough fluid to leak all the way onto the wheel.....

It's hard to see the state of the internal seals of the Stillen AP rear kit because there are dust boots covering them. It's typical for the dust boots on the rear to look completely cracked and destroyed. But that's not necessarily a sign of needing service. Those "high temp" dust boots get destroyed after one day on track. So, for the rear, you are searching for moist-looking brake pad dust hanging out inside the caliper near the pistons.

In my experience with BBKs, the aging process is gradual. You get signs before an outright failure occurs. But the user needs to be looking for them. I think putting these three things on your radar is a good place to start.

(I just saw SYT_Shadow saying he got 100+ days. That would NOT be possible with my Stillen kit. The first time I sent the kit to Stillen for rebuild, they said it was DEFINITELY time.....even past the time.....and that was less than 40 track days.)

This

I rebuilt mine when I saw signs of brake fluid seeping out, when taking it apart the seals and dust boots were completely destroyed.

[roastbeef]

just an FYI for anyone with oem brakes... my rears started to sort of seize at some point when the dust boots failed. no fluid leaking out that i could see, but when i got my ap's put on today, my mechanic told me the calipers were failing.
i posted in another thread that the pads were starting to not completely brush away the rust on the rotor face after washing the car (rust ring towards the center of the rotor). i wasn't surprised they were taking a dump, just though i would pass it on this was a sign.

[SYT_Shadow]

Originally Posted by dogbone

(I just saw SYT_Shadow saying he got 100+ days. That would NOT be possible with my Stillen kit. The first time I sent the kit to Stillen for rebuild, they said it was DEFINITELY time.....even past the time.....and that was less than 40 track days.)

A couple notes on that
-I don't usually run Rcomps, just RE71's etc
-The insanely fat pads of the PFC BBK probably keep the pistons and calipers at pretty low temp. Pad material insulates

I think now that you have similarly fat pads you may notice a longer maintenance interval

[admranger]

Originally Posted by SYT_Shadow

A couple notes on that
-I don't usually run Rcomps, just RE71's etc
-The insanely fat pads of the PFC BBK probably keep the pistons and calipers at pretty low temp. Pad material insulates

I think now that you have similarly fat pads you may notice a longer maintenance interval

Nah. It's PFC. Magic. Just wish I could afford magic, though I have no need for it anymore it seems. Track days are a fading memory (Laguna August 2016 was my last one).

[SYT_Shadow]

Originally Posted by admranger

Nah. It's PFC. Magic. Just wish I could afford magic, though I have no need for it anymore it seems. Track days are a fading memory (Laguna August 2016 was my last one).

PFC does seem like magic. It's really incredible to outbrake cup cars with no ducting and no issues.

I haven't done a HPDE in a long time! We need spring to arrive!!

[dparm]

Originally Posted by SYT_Shadow

-The insanely fat pads of the PFC BBK probably keep the pistons and calipers at pretty low temp. Pad material insulates

Yep, a thicker pad and/or not running it all the way down will keep the caliper temps cooler. Pretty easy to prove with the stickers/paint.

[SYT_Shadow]

Originally Posted by dparm

Yep, a thicker pad and/or not running it all the way down will keep the caliper temps cooler. Pretty easy to prove with the stickers/paint.

Yes. I run them down to the backing plate thickness so eventually they do see lots of heat, but still I'm impressed with the durability