135i Brake Pistons Revealed

[takahashi]

Originally Posted by Yearofthe1

You guys need to note that these guys were using non-OEM brake pads. Who knows what could have happened here?

That is still a :bs: as other manufacturers brakes and even the ones within the BMW range work well with aftermarket pads. This is not an excuse and just a self protective explanation. They just have to admit the brake is shit.

[Addict...Nah Im A Junkie!]

Yeah I would send this on to Roundel and the other US publications too. Remember, the squeaky wheel get the grease!!

[MatthewDFW]

Great info! Please keep us posted here. Worth keeping eyes open.

[imported_ralphwarren]

I talked to the guys at GMG Racing (Porsche experts). None of them have ever seen a ceramic insert in a Porsche brake caliper piston. They know of the ceramic Porsche rotors of course and how careful you need to be with them when changing the pads or working on the suspension. A dropped wrench in the right place will chip the rotor - but that's not our issue here - other than a clue that you have to be very careful when swapping out pads.

I also talked to the guys at Evosport. They are aware of the problem and are developing a piston replacement kit and titanium backing plates.

Both of those items should be a big help! :w00t:

To comment on people's thoughts on BMWs willingness to address this problem... true, it may have only happened a couple times so far and true both cars are race cars, *BUT* this problem will absolutely propagate down to the instructor and driving school student level soon.

I'll keep you posted as I hear things.

-Ralph

[cuizhuoyi01]

hope some piston replacement kits will come up soon. no hope for recall.

[Evolution Racewerks]

That's great. At least this issue has a solution in the horizon. The pains of being one of the first to race a new car I guess.

Originally Posted by ralphwarren

I talked to the guys at GMG Racing. None of them have ever seen a ceramic insert in a brake caliper piston. They know of the ceramic rotors of course and how careful you need to be with them when changing the pads or working on the suspension. A dropped wrench in the right place will chip the rotor - but that's not our issue here - other than a clue that you have to be very careful when swapping out pads.

I also talked to the guys at Evosport. They are aware of the problem and are developing a piston replacement kit and titanium backing plates.

Both of those items should be a big help! :w00t:

To comment on people's thoughts on BMWs willingness to address this problem... true, it may have only happened a couple times so far and true both cars are race cars, *BUT* this problem will absolutely propagate down to the instructor and driving school student level soon.

I'll keep you posted as I hear things.

-Ralph

[takahashi]

Fred, it is not a pain. It is a thrill being a pioneer.

[HP Autosport]

Originally Posted by ralphwarren

I just found this in text written by Porsche regarding the 911 GT3.

"To reduce the transmission of temperatures from the brakes to the hydraulic fluid, brake caliper pistons are separated by heat-insulating circonium ceramic inserts."

Hi Ralph,

We are talking about a production caliper here...I don't think it was designed or meant to take the abuse of BMWCCA Club Racing. Are you running brake ducting?

I have heard titanium shims may help with heat management when installed between the pad and pistons. Have you use temperature paint to see where you are at?

Harold

[Orb]

Originally Posted by ralphwarren

After finding some serious cracking in the face of the pistons in the 135i race car, a lot of speculation has been floating around the Internet about the construction of the pistons, the performance of the pistons and the reasons as to why the face of the pistons were cracking.

Similar issues have occurred with other teams as well already.

This thread is basically a continuation of...

http://www.1addicts.com/forums/showthread.php?t=18453


On to the pics and findings...

Attachment 13434

Attachment 13435

At first, we though the pistons were made of aluminum.

We thought the race pads we were running (Hawk HT10 from Turner Motorsports) on the race car were getting so hot that the aluminum was melting.

Turns out, we were wrong. They are made of stainless steel and a ceramic insert.

We are not using any brake cooling at this point, yet we have added some weight (cage) and some power (Dinan Software) to the car - not fun for the brakes. Especially when you factor in racing tires (Nitto NT01) and racing at heaving braking tracks (Buttonwillow and Infineon).

We took the car to the dealer and of course they didn't want to have anything to do with it. Spreading the news to BMW of North America or researching this problem was of no interest to them.

We connected with a local North American Brembo distributor and shared some pics with them, but I don't think we got to the right Brembo people because I got the feeling that all they wanted to do was use this piston cracking issue to sell the 135i BBK kit they have for sale (which actually does look awesome - and Fred uses on the Evolution Racewerks 135i - but we can't use due to the Stock-Class we run in with BMW).

It was mentioned that the pistons have a ceramic insert similar to a Porsche of some sort. I thought - Hmmm… lets take a closer look at this.

I had some time today to remove the pistons from the 135i brake calipers. Here are my findings....

Attachment 13436

The 3 piston sizes are 28mm, 32mm and 36mm.

They are a total of 30mm tall each with the cup taking up 22.5mm and the ceramic insert taking up 7.5mm.

Attachment 13437

It seems the pistons are in fact made up of 2 parts, a main cup and a ceramic insert.

The ceramic insert seems to be gently pressed into the cup and held in place with (what I think to be) green Loctite - which is sleeve retainer.

Attachment 13438

***Please note, I did crack the ceramic a bit on all 3 of the pistons as I removed them from the caliper. They were not this badly cracked prior to the removal.

Attachment 13439

Attachment 13440

Attachment 13441

The piston backs are flat and made of stainless steel.

Attachment 13442

The ceramic insert has a small hole in it to allow the internal air pocket to expand and contract. I used this hole to remove the pistons by making a small hook out of a thin screwdriver.

Attachment 13443

Attachment 13444

The dust seal is then inserted in the gap between the piston body and the ceramic insert.

Attachment 13445

We are really hoping for BMW to address this issue. Regardless of the fact that we race this car, BMW needs to realize that the 135i is going to be taken to driver schools and driven hard by both students and instructors.

Yes, we know ceramic is a very fragile material. Yes, we have been changing pads a lot (street pad to to track pad and visa verse X10). Track rats are going to be swapping out pads just the same once track pads become more readily available.

Another thought on ceramic being a bad choice here is due to the fact that over the years, people are going to be rebuilding these calipers with new seals and dust boots. Rebuilding more standard BMW calipers in the past (E30, E36 or E46 M3 for example) has never been a problem due to the 1-piece steel design of the brake pistons in those cars. This fragile ceramic material is going to easily break in the hands of your average shade-tree mechanic - leaving him stranded.

Whatever discussion and additional speculation follows this post, one thing remains clear, this is a huge issue and needs to be addresses ASAP! This problem will show up for the life of the car unless something is done about it.

Dear BMW & Brembo - Dibs on being first in line to have the recall performed. If you like more info or detail on this, you can reach me at ralphwarren@yahoo.com

-Ralph Warren

I think the material that one use meant to say is they are zirconium based ceramic. It looks like aluminum might be one of the components of the matrix which has melting temperature of 1100 F. Might be wroth noting how much noise the brakes were making as well.

As a Mechanical Engineer I wouldn’t want to see this on my plate. I would report this to proper government authority and they will act on this complaint. Due to nature of this part this is unacceptable as the design requirements would have to include after market brake pads would be used. The response you are getting beyond being negligence and they should be passing this one to the appropriate engineering department for further review.

This is a really ugly mark on Bermbo….they should clean this up ASAP before this get onto the bogs.

Orb

[Evolution Racewerks]

LOL, you don't know my life and the sleepless nights hehe.

I don't think Ralph/Scott thinks this brake issue is a thrill either.

Originally Posted by takahashi

Fred, it is not a pain. It is a thrill being a pioneer.

[Evolution Racewerks]

I think the resolution of this issue should be and can only be solved by BMW. It's an OEM part. Yes, it was built by Brembo, but only BMW can solve this as OEM parts are licensed to them. Even if Brembo wanted to resolve this, I don't think they can legally. For example, Brembo won't be able to sell replacement ceramic inserts to the public even though they make it because legally, that is a BMW part (through licensing). BMW can sue them for this. The part must be sold through BMW and the choice comes down to BMW whether or not said part is sold seperately or not.

As I mentioned in another post, Brembo makes these inserts in 3 different materials, titanium, stainless steel and ceramic. These choices are given to BMW. BMW makes the choice which material they're going to use. Of course given a choice, they chose the most economical one that will suit the job (given the parameters of use), which was ceramic. Now, it's up to BMW to resolve this issue by 1) warrantying the part (which I highly doubt they will), 2) sell the ceramic inserts separately (which I think with enough public outrage, would be the most likely option they will choose), 3) have a stainless steel insert made (again, highly unlikely).

Now, I totally think that there needs to be accountability, but being a realist, I doubt anything will be done by BMW at this moment. My reasoning 1) not enough people have this issue at this time and BMW won't care about the 2 people out of thousands who have the car 2) they can easily claim that these cars were raced which no car manufacturer (including BMW) will ever condone or warranty, no matter how much their marketing is based on performance driving.

I want to have a resolution to this, as I am directly affected. I'm part of the broken caliper camp too.

Originally Posted by Orb

I think the material that one use meant to say is they are zirconium based ceramic. It looks like aluminum might be one of the components of the matrix which has melting temperature of 1100 F. Might be wroth noting how much noise the brakes were making as well.

As a Mechanical Engineer I wouldn’t want to see this on my plate. I would report this to proper government authority and they will act on this complaint. Due to nature of this part this is unacceptable as the design requirements would have to include after market brake pads would be used. The response you are getting beyond being negligence and they should be passing this one to the appropriate engineering department for further review.

This is a really ugly mark on Bermbo….they should clean this up ASAP before this get onto the bogs.

Orb

[pkcormier]

I have attended several track events with my stock 135i calipers with both stock pads and cool willy's. Since neither pads cut the mustard, I have purchased a set of HT-10's will use them at my next weekend event in a couple weeks. I looked at my pistons this weekend and althought the ceramic inserts look fine, the dust seals are cracked and peeling away.

My question is for Ralphwarren or for anyone else experiencing much more significant degredation of the pistons is, what, if any, reduction in braking performance did you experience with the brakes in that condition, or did you just notice it when you were changing pads? In anyones opinion, what would be the results of complete failure of the ceramic inserts? Would the car at least be driveable on the street? If you had relatively thick pads, wouldn't the pistons still have enough travel to provide adequate braking to "get you home"?

[adc]

Originally Posted by Evolution Racewerks

Now, I totally think that there needs to be accountability, but being a realist, I doubt anything will be done by BMW at this moment. My reasoning 1) not enough people have this issue at this time and BMW won't care about the 2 people out of thousands who have the car 2) they can easily claim that these cars were raced which no car manufacturer (including BMW) will ever condone or warranty, no matter how much their marketing is based on performance driving.

Based on how long BMW has dragged their feet in previous such situations - looking just at the two most recent and notorious, the S54 crank bearing failures and N54 HPFP failures - there will have to be far more numerous failures and vociferous complaints before they lift a finger. After which, they will fix the problem perfectly.

I don't doubt this is a failure they will see on various cars, before and after the 4yr/50k mi warranty and maintenance expires. But unfortunately, it may take a couple of years before any action is taken.


Frankly, if I had a new 135i now, I'd remove the ceramic inserts, take them to a machine shop and ask for a set of stainless steel replacements. Far less hurt and inconvenience, let alone potential safety issues.

[WAY]

Originally Posted by ralphwarren

I talked to the guys at GMG Racing (Porsche experts). None of them have ever seen a ceramic insert in a Porsche brake caliper piston. They know of the ceramic Porsche rotors of course and how careful you need to be with them when changing the pads or working on the suspension. A dropped wrench in the right place will chip the rotor - but that's not our issue here - other than a clue that you have to be very careful when swapping out pads.

I also talked to the guys at Evosport. They are aware of the problem and are developing a piston replacement kit and titanium backing plates.

Both of those items should be a big help! :w00t:

To comment on people's thoughts on BMWs willingness to address this problem... true, it may have only happened a couple times so far and true both cars are race cars, *BUT* this problem will absolutely propagate down to the instructor and driving school student level soon.

I'll keep you posted as I hear things.

-Ralph

Hi Ralph, did Evosport give a timeframe? Maybe there is life in these old calipers of mine still. I am fairly happy with the performance and see no sense in upgrading unless I can't solve this piston issue...

[WAY]

Originally Posted by pkcormier

I have attended several track events with my stock 135i calipers with both stock pads and cool willy's. Since neither pads cut the mustard, I have purchased a set of HT-10's will use them at my next weekend event in a couple weeks. I looked at my pistons this weekend and althought the ceramic inserts look fine, the dust seals are cracked and peeling away.

My question is for Ralphwarren or for anyone else experiencing much more significant degredation of the pistons is, what, if any, reduction in braking performance did you experience with the brakes in that condition, or did you just notice it when you were changing pads? In anyones opinion, what would be the results of complete failure of the ceramic inserts? Would the car at least be driveable on the street? If you had relatively thick pads, wouldn't the pistons still have enough travel to provide adequate braking to "get you home"?

What sort of events do you do? If it's auto-x, I suspect you will be ok. I have a feeling this is temp related and auto-x doesn't get the sort of temp that you get on a fast track.

[pkcormier]

The events I attend are HPDE type events at road courses. Motorsport Ranch in Cresson, TX, Texas World Speedway in College Station, TX, the Roval at Texas Motor Speedway, and most recently at Eagles Canyon, Denton, Texas. A couple of these tracks are hard on brakes, that's why I've upgraded to HT-10 pads. I intend to keep tracking the car despite the potential insert failure. And Since my car is stock with the exception of camber plates, I may be able to get a dealer to react to my problem if there is a failure.

[esses]

This is a serious concern for non-tracked cars as well. Even if we assume this only happened because aftermarket pads were used by people who have posted here.

Brake pads will always wear out. BMW can not require that we always replace worn out pads with BMW pads. ESPECIALLY by ignoring that non-oem may cause catastrophic failure of a braking system which is life-threatening is most circumstances.

The most mundane Smart Car driver will eventually be in a situation where their brakes are subjected to similar heat as that of a tracked car. You don't have to be the "ultimate driving machine" driver to heat up your pads. In these cases the rotors were not warped so we really are not talking about excessive heat.

After reading these posts I make it a point to engine brake all the time (which is no solution). Really. This is bad stuff. I can deal with high pressure fuel pump issues - a high pressure fuel pump failure probably will not kill me. Brakes are an entirely different ball game.

Thanks for all the updates guys. When BMWNA calls me to follow up on my recent cam shaft sensor failure you bet I'm going to bring this up.

[Yearofthe1]

Originally Posted by esses

BMW can not require that we always replace worn out pads with BMW pads. ESPECIALLY by ignoring that non-oem may cause catastrophic failure of a braking system which is life-threatening is most circumstances.

There might be a problem with this statement.

From the K&N filters website regarding car warranties and use of aftermarket parts:

"It is against federal law in the United States for a manufacturer to require the use of a specific brand of air or oil filter unless it provides a replacement air or oil filter, free of charge, under the terms of the vehicle warranty. For a more thorough discussion of this law known as the Magnuson-Moss Warranty Act..."

I don't know if this also applies to break pads, but I'm at work right now and can't look into this too extensively. I just remembered K&N's site specifically referencing this subject.

[atr_hugo]

I'm not sure heat is the issue - the inserts are disintegrating and yet they are ceramic which are intended to be used in extreme heat conditions.

Rather, I would first suspect that there's some 'chattering' (repeated hammer blows) between the aftermarket pads and the pistons that's causing the fractures/disintegration.

[m7ammed]

Originally Posted by Yearofthe1

There might be a problem with this statement.

From the K&N filters website regarding car warranties and use of aftermarket parts:

"It is against federal law in the United States for a manufacturer to require the use of a specific brand of air or oil filter unless it provides a replacement air or oil filter, free of charge, under the terms of the vehicle warranty. For a more thorough discussion of this law known as the Magnuson-Moss Warranty Act..."

I don't know if this also applies to break pads, but I'm at work right now and can't look into this too extensively. I just remembered K&N's site specifically referencing this subject.

http://en.wikipedia.org/wiki/Magnuson-Moss_Warranty_Act

just found it on Wiki website

[1erich]

I would imagine that because BMW replaces brake pads under warranty (in the USA at least) that you'd be SOL after the warranty expires and you use aftermarket pads.

[Yearofthe1]

Originally Posted by adood84

http://en.wikipedia.org/wiki/Magnuson-Moss_Warranty_Act

just found it on Wiki website

Yeah, checked there already, but no mention of warranty coverage when maintainence parts are covered under warranty.

I do love Wikipedia though!