Anyone experience or heard of this happening before?

[jafo1701]

So my 135i has been in storage since late September of 2014. I finally decided to take out of storage. To my surprise, when I hit the brake pedal the pedal went to the floor. I checked my brake reservoir and it was empty. Upon closer inspection it looked like the brake fluid had leaked out from the calipers at the pistons. And it happened on all 4 of the calipers. I did rebuild the Calipers with the RB kit in Spring of 2014, zero problems thoughout the entire spring/summer/fall of 2014, 6 track days and numerous autocross events.

I inspected all the calipers, cleaned em up. Flushed and bled they system with new fluid and the brakes seem to be working properly with no leaks. Guess I'll check em tomorrow to see if there are any leaks. Anyone have any ideas how this happened?

[_Ryan_]

There was mention of the seals on the RB kits leaking, can be found on this forum somewhere.
Perhaps contact RB and see if they have changed the seal design?

[Bullitt]

There was one very short post of a kit leaking, but there were no details provided like jafo did.

For what it's worth, I personally know someone who's been running this kit for over a year with no issues. And he is a very fast driver who attends track events frequently and pushes the brakes to their limits.

Maybe the seals weren't installed properly or unseated over time? Did you lightly lube the seals and/or the pistons with brake fluid during installation? However, it is odd that they were fine through most of last year's activities but suddenly leak with inactivity.

Contact RB and please share what they say. I recently ordered this kit!

[jafo1701]

I don't recall if I lubed em with brake fluid. It was a year ago when I did it. Well if the pistons weren't lubed then, they are now. My friend who is a mechanic said he has heard of this before after long periods of storage. Something about the system losing pressure from lack if use and unseating the seals. I'll contact RB and see what they say.

[jafo1701]

Well I checked it this morning all the fronts are leaking. Oddly the rears are not. Maybe the fronts leaked enough that it lost pressure and caused the rears to leak. Regardless I'll have to replace all the dust boots and seals as these are the high temp dust boots and once they get coated with brake fluid they are done. I'm trying to contact Racing Brake, but their website isn't working properly. Everytime I click on contact it goes to a blank page. Anyone know their e-mail address? Worse case scenario I just buy the factory seals and dust boots. They should work with the racing brake Pistons I would think.

[Bullitt]

Here's a wild guess. If the seals weren't lubed at install, the pistons could have gripped the seals due to dry friction and shifted them slightly out upon first application of the brakes following the install. Then slight pad knockback after release of the brakes would push the pistons back into their bores just slightly enough for the unseated seal to seal temporarily. Upon inactivity, gravity and pressure in the system would push the pistons slightly out slowly over time just enough to unseal the seal that was already slightly unseated from the very beginning. In any case, I'm very curious to know what really happened.

Their email address is service@racingbrake.com. I confirmed this with them earlier this month that the stock seals are indeed compatible with the RB pistons.

[dcaron9999]

Subscribed, as the RB kit was at the top of my shopping list.
They seemed like the solution for 135i owners who visit the track often...

[jafo1701]

Either way I have brake fluid all over the high temp dust boots, which has destroyed them. I'll have to replace them. So if RB doesn't send me a replacement kit I'll just order the stock dust boots from BMW. They are pretty cheap, it just cost me time more then anything. The pistons are still good. They are suppose to vent heat better and transfer 1\10th of the heat of the stock pistons so hopefully stock dust boots with RB pistons with hold up better.

[Bullitt]

RB is currently out of stock on their seals for several weeks
They currently have stock of the dust boots though.

[dcaron9999]

Originally Posted by jafo1701

Either way I have brake fluid all over the high temp dust boots, which has destroyed them. I'll have to replace them. So if RB doesn't send me a replacement kit I'll just order the stock dust boots from BMW. They are pretty cheap, it just cost me time more then anything. The pistons are still good. They are suppose to vent heat better and transfer 1\10th of the heat of the stock pistons so hopefully stock dust boots with RB pistons with hold up better.

The BMW stock dust boots will burn up and crumble easily. At least mine have. I guess we need to consider these as wearable consumable items, and replace them once a year when visiting the track regularly.

[dcaron9999]

Originally Posted by Bullitt

RB is currently out of stock on their seals for several weeks
They currently have stock of the dust boots though.

Im getting less impressed by the day with RB. Might have to look elsewhere when the time comes for me.

Other than BMW or Stoptech pistons+seals+boots, there is not a ton of options out there...

[scotty_miller]

Check out zeckhausen.com I tore down my calipers when I had mine powder coated. Came with dust boots and pressure seals. I haven't got my car out of storage yet so I can't comment on the longevity of them just yet. I wasn't impressed with racing brakes attitude towards me when I called to ask them a couple questions about their product and they hung up on me. So I checked them off the list real quick.

[Bullitt]

Originally Posted by dcaron9999

Im getting less impressed by the day with RB. Might have to look elsewhere when the time comes for me.

Other than BMW or Stoptech pistons+seals+boots, there is not a ton of options out there...

Unfortunately, RB's are the only ones that are vented and made of stainless steel, which is superior to the other available option(s).

Jafo, I assume you used compressed air to install your pistons. What PSI did you set your compressor to? I just looked at the DIY by yandy and the stated 90psi seems excessively high which could unseat the pressure seals (of the other freshly installed pistons) during the install process, especially if the other pistons/seals weren't lubed. I'd imagine 10psi or below would be sufficient to eject each old piston without disturbing the other new seals.

[jafo1701]

RB is sending me replacement high temp dust boots. Unfortunately they don't have the seals in so had to order those from BMW. No issues with the dust boots or pistons so this should work out.

When I took apart my calipers I did it all at once. Cleaned it all out. Then reassembled everything together at the same time. I don't think I I used any compressed air on the rebuild process. But that was a year ago, if I do have to this time I'll be sure to reduce the psi. I'll make sure all the pistons and seals are lubed with brake grease. With the high temp dust boots have to be extra careful that no brake fluid gets on them.

[fe1rx]

Originally Posted by jafo1701

Unfortunately they don't have the seals in so had to order those from BMW.

You can get them from BMW? Can you post the part numbers please?

[Bullitt]

May I ask how you removed the pistons?

When it all leaked, did you notice any leak at the brake line connection to the caliper?

[jafo1701]

Originally Posted by Bullitt

May I ask how you removed the pistons?

When it all leaked, did you notice any leak at the brake line connection to the caliper?

The leak definitely came from the piston area. I pulled the calipers off individually to check. Removed the brake pads and inspected the calipers. The Lines and connections are all fine. I used compressed air to remove the pistons from the calipers.

[Bullitt]

Originally Posted by jafo1701

...

When I took apart my calipers I did it all at once. Cleaned it all out. Then reassembled everything together at the same time. I don't think I I used any compressed air on the rebuild process. But that was a year ago, if I do have to this time I'll be sure to reduce the psi. I'll make sure all the pistons and seals are lubed with brake grease. With the high temp dust boots have to be extra careful that no brake fluid gets on them.

I was referring to the first time you did this a year ago since you had mentioned otherwise.

[Bullitt]

Originally Posted by fe1rx

You can get them from BMW? Can you post the part numbers please?

Looks like it's 34116780507. (Thanks to member turbowolfe who provided this in different thread)

[dcaron9999]

Originally Posted by Bullitt

Looks like it's 34116780507. (Thanks to member turbowolfe who provided this in different thread)

Looks like this includes both the dust boots and o-rings.
Rear part # is 34216780515.
You need two of each ...

[FuelTech]

Experienced the exact same issue with the RB SS piston and seal kit.The RB seal kit has issues at low temperatures. Everything was O.K until the temperature dropped to 0 degrees celsius (32 degrees F) then the front as well as the rear calipers began leaking. RB has no replacements and was not very helpful to provide an alternative source to obtain the parts. The problem is that the front kit from BMW, from what I have discovered, is only the dust seals. The rear kit is oil pressure seals and dust boots. Zechausen Racing has a Centric seal kit for the front & rear calipers. Dave was extremely helpful and went to great lengths to get these parts. Will update once I rebuild the calipers.

[fe1rx]

Originally Posted by dcaron9999

Looks like this includes both the dust boots and o-rings.
Rear part # is 34216780515.
You need two of each ...

Originally Posted by Bullitt

Looks like it's 34116780507. (Thanks to member turbowolfe who provided this in different thread)

Both of these kits contain only the dust boots (despite the description on the ECS website). I have ordered both in the past.