Official Fix for Shattered Brake Pistons

[larryn]

As many others have found, the ceramic pistons on the 135i's calipers are prone to overheating, cracking and crumbling to dust. It happened to me last week.

After researching with BMW and Brembo, they do NOT sell replacement pistons and seals. So, I started off emailing StopTech, after receiving a tip via PM here.

StopTech forwarded my inquiry to zdeckhausen, and Dave Zeckhausen emailed me with the following response:

Originally Posted by Dave Zeckhausen

Some BMW 135i drivers have replaced the destroyed metal/ceramic pistons in their 135i Brembo 6-piston calipers with StopTech aluminum pistons that are typically used in the ST-60 6-piston StopTech calipers.

To rebuild your calipers, you will need two each of the following boot and seal kits:

28mm: http://store.zeckhausen.com/catalog/...oducts_id=6533
32mm: http://store.zeckhausen.com/catalog/...oducts_id=6535
36mm: http://store.zeckhausen.com/catalog/...oducts_id=6537

And four each of the following "short" (29.5mm long) caliper pistons:

28mm: http://store.zeckhausen.com/catalog/...oducts_id=2916
32mm: http://store.zeckhausen.com/catalog/...oducts_id=2919
36mm: http://store.zeckhausen.com/catalog/...oducts_id=2921

So, if you are looking for insurance, for about $500, you can replace the fragile ceramic units in your front calipers with well machined pieces.

[UdubBadger]

thanks

[TimMc]

Thanks larryn!

[Groundpilot]

Very nice. Thank you Larryn.

[The1]

very useful, I'll be more likely to stop on my breaks for often now

Thank you!!

[timhatimay]

I was scared of this issue, and found it a total bummer given the expectation of the brakes, but this is great news and a great find! I guess with some good pads, fluid, and new pistons these brakes could be quite competent for a stock system (although the rotors are still quite thin). Thanks for the research!

Tim

[nordique14]

Thanks for finding this out!

Let us know when everything is installed and how it works out.

[The1]

Originally Posted by maxnix

Unfortunately, this doesn't cure the seal design problem of the Brembo pistons.

it replaces them.

it's replacing the boots, seals, and pistons, I just hope the boot and seal is better material then the stock material. I can only hope it is.

[1erich]

Nice work larryn, as always, your contributions to the 1addicts community are greatly appreciated. I have some brake work due soon and I'll be checking the pistons/seals very closely! Just nice to know that there's a cheap solution if I find any problems.

[deek]

are there any disadvantages of having aluminum pistons?

[deek]

...weird double post...

[e82n54]

Originally Posted by deek

are there any disadvantages of having aluminum pistons?

Has anyone done this? Is it worth it or is it better to go with a big brake kit instead?

[spk74]

So if I'm reading the original post correctly, our 6-piston calipers have 3 pairs of different-sized pistons?

[pixelblue]

The pistons on our brembos are the same as used on Porsche. So the stories about their demise are a bit over blown and the ones that have failed could have a lot to do with abuse

[Lubo]

Originally Posted by pixelblue

The pistons on our brembos are the same as used on Porsche. So the stories about their demise are a bit over blown and the ones that have failed could have a lot to do with abuse

I just found this out. I was swapping in my new pads. And this is with 7 tracks days and 2 sets pads gone. One of them being EBC yellow. Looks like heat killed it. Larry were you able to test the "rebuild kit" and see if it hold up any better. My car is off duty now because of this. $500 investment will cost me at least one event, bummer.....

[JB135MDCT]

I don't see any reason why you can't use your brakes. I just see some cracked seals, which is expected for track events. Actually, they look better than expected.

No reason to loose a track day.

[pixelblue]

Lubo, I just checked my brakes this past weekend and I was surprised how clean they looked after 5 track events. I was able to push the pistons back by simply pushing on them. Not sure how to explain this but I am not too hard on brakes. Yours def looks cooked. Planning to change the calipers or repair the pistons?

[Lubo]

Originally Posted by pixelblue

Lubo, I just checked my brakes this past weekend and I was surprised how clean they looked after 5 track events. I was able to push the pistons back by simply pushing on them. Not sure how to explain this but I am not too hard on brakes. Yours def looks cooked. Planning to change the calipers or repair the pistons?

I do not know at the moment. I need to research this issue. Thing is my car is a lease, so I do not really feel like spending $500 on a rebuild as I need to do a return next March. At the moment buy out at the lease return is out of questions as my family grew last year and I need something bigger, fingers crossed for E90 M3.

Whatever I'll do I am definitely fabiricating some sort of cooling hose as this is clearly heat related. It also has to do with what track you drive at. I did 3 events at Monticello last year, and that track is hard on brakes. This modifications is a never ending battle. You improve in one area only to find shortcomings in another.

[Lubo]

Originally Posted by JB135MDCT

I don't see any reason why you can't use your brakes. I just see some cracked seals, which is expected for track events. Actually, they look better than expected.

No reason to loose a track day.

It is hard to see in some of the pictures but out 12 rubber seals 9 were cracked. Once the boot and seal is broken you will get contamination into your brake fluid. After enough negligence your pistons may get seized, overheat and crack completely. Not something I am willing to sacrifice or experiment with as I carry my 8 month old in the back seat couple times a week.

[Amalfitano]

Didn't Berk find Shims to put in between the pistons and the backing plate of the pads that kept everything in check? I don't know if Autocross generates enough heat to have this issue since we don't even approach fade, but i could be wrong. At least i haven't felt any fade even with two drivers and consecutive re-runs, doing 4 60 second runs with 5 minute breaks. But maybe i was wrong...

For autocross, honestly the stock pads seem to do their job pretty well. I might try some others, but i might also protect the pistons with the shims. $200 for shims and bedding a little bit more than usual to get the pads to fit sounds a lot better than $500 replacement pistons.

[Lubo]

Originally Posted by maxnix

Part of it probably has to do with how much material (mass) is left on the pad when it is super heated by track like repeated applications with insufficient cool off periods. The less there is, the more heat transfer there is to the piston, seals and fluids.

Unfortunately, neither the Porsche nor the Stop Tech replacement parts change the problem with the dust seal design on the caliper pistons. Tehy cannot live at sustained high temperatures.

I use a) titanium plates and b) always replace pad when there is around 1/4 of a pad material left c) car never came off the track without a cool down lap. I just expected better from these Brembo's, for god's sake my econo hatch golf didn't have any problems after years of track abuse.

[Lubo]

Originally Posted by Amalfitano

Didn't Berk find Shims to put in between the pistons and the backing plate of the pads that kept everything in check? I don't know if Autocross generates enough heat to have this issue since we don't even approach fade, but i could be wrong. At least i haven't felt any fade even with two drivers and consecutive re-runs, doing 4 60 second runs with 5 minute breaks. But maybe i was wrong...

For autocross, honestly the stock pads seem to do their job pretty well. I might try some others, but i might also protect the pistons with the shims. $200 for shims and bedding a little bit more than usual to get the pads to fit sounds a lot better than $500 replacement pistons.

No way auto-x would do it. I did about 20 auto-x event with the car and 7 days of HPDE. I got the stock pads to fade, but once I upgraded to EBC I didn't have any issue with braking.