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Discussion Starter #21
I just wanted to update you guys as I have seen a bunch of threads on this topic - failure of the brakes once they get too hot. This past weekend I took the calipers off and rebuild them. Quite easy to do actually. The Brembro calipers use aluminum pistons that are coated with a thin gray material. (I suspect this is to prevent corrosion from steel in direct contact with aluminum.) Interestingly, when I tore apart the front calipers, two or three of these pistons had pitting and chips in the gray surface material. This defect extended along the piston into the caliper past the internal seals. I suspect that these defects would allow air to enter the system without allowing fluid to leak out. I replaced the pistons with aftermarket stainless steel pistons and put new seals and dust covers.

I am running Nelson Ledges next week and will post an update. If this solves the problem I will post photos of the pistons - both normal and one with the defect in surface material.
 

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I am running Nelson Ledges next week and will post an update. If this solves the problem I will post photos of the pistons - both normal and one with the defect in surface material.
Interested to see how this works out for you! Out of curiosity, what did the rebuild cost in parts?
 

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Discussion Starter #25
FINALLY GOT IT SOLVED!! No more brake issues!

So the rebuilding of the calipers worked. No fade even after all day of hot laps. I suspect this is the issue that others have been experiencing with brake fade, soft pedal or brake failure.

Calipers 987.jpg Calipers 987.jpg
When I took the calipers apart this is what I found in the front. The normal pistons have a smooth gray coating but as you can see some of this coating was pitted and chipped off. I suspect this is where air was entering the system under extreme conditions like hot laps. I rebuild the calipers following videos on line - pretty straight forward but took me half the day nonetheless. The one thing that seemed easy but was a PITA was using compressed air to remove the calipers. One piston would come out but not the other 3. I ended up making shims so they would all come out nearly all the way without any one flying out prematurely.

I purchased rebuild kits from RB performance part #BP-422BS and BP-404SP with high temp (blue) dust seals. I used new stainless steel pistons on the front calipers (the pitted ones) and replaced all the dust rings and inner seals on all 4 calipers. Bled the system and now I have confidence inspiring brakes again! I would recommend everyone rebuild their calipers if they are experiencing these issues. The total cost was about $350.00 give or take. With each new caliper around $450-$500 each, this seemed like a no brainer.

To answer the few other questions outstanding - I run Nitto's NT01 and carbotech brake pads.
 

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Has to be more to it than the piston rebuild though -
 
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