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Hooligan
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Discussion Starter · #1 ·
This happened today on the trail - on one of the trails at Bull Mountain in north Georgia... as I was descending I lost all rear brake - you could hear it scraping, apparently the pad separated from the metal part it was mounted to - a scary few seconds but no harm done.

The part that concerns me is that these brakes/pads came on my new Turner Sultan, which has only about 175 miles on it. I guess I'll replace the front pads too.

Wood Line Technology Black Grey
 

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i just had the same thing happen earlier today--lost my rear brake coming down a technical hill--hadn't hit anything, nor was i overusing them (they were not hot). the brakes themselves are 3 weeks old--barely used. was able to pull over using my front brake, only to find out the metallic contact pad itself was missing--it had literally separated from the metal backer. see pix below.

scary stuff. i'm glad this defect did not cause me bodily harm. if it'd been the front brake, who knows. luckily also had a replacement XT set (organic) with me, so was able to keep riding after also checking the brake setup itself. took off the assembly for inspection, and it was seated well, with no other apparent damage.

bad glue? rivet formation? combination of the two?

Circle
Finger Tan Nail Beige Circle
Tan Beige Metal Circle Square
 

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If that happened to me, I'd send them back to Shimano
Absolutely. From experience they are very good at sorting issues out, I've had new pads and whole new brakes off them.

You also want them to know about it. It looks like a design or manufacturing stuff up so the more they know about it the quicker they'll fix it.

Incidentally, looking at the pictures it looks like the part which separated is still retained by the pin and has those two bumps on the back to locate it on the heat-sink. Why did the brakes fail? Why didn't that pad stay in place and still work? Could you see exactly what had happened in there?

Maybe Shimano are having trouble with metallic pads as they are kinda new to that game.
 

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Hooligan
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Discussion Starter · #7 · (Edited)
As a follow up, I called Shimano and they referred me to any LBS. They were not interested in talking to me directly. Unfortunately, I bought my bike direct from Turner (no Turner dealers in Georgia) - my local LBS would not warranty. So I bought new pads and went on my way. Retail on those pads is $42 a set, by the way.

I wrote a letter describing what happened, enclosed what was left of the pads, and mailed them to Shimano. If I get a response I'll post here.
 

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Hooligan
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Discussion Starter · #8 ·
Here is the end of the story - a box showed up on my doorstep today with two new pairs of replacement pads from Shimano (I asked for two pair - I told them in the letter that I didn't trust the matching pair). All's well that ends well I guess and hopefully that will not happen again.
 

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All is not well. It looks like this isn't an isolated incident. This is dangerous stuff. If this happened to me I'd be far more pissed than you are/were. We are talking about potential death.

Not good. I'm SO happy I just bought a pair of XTs to toss on my bike.
 

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Has this happened to anyone with the resin pads recently? I have two sets on order that will be delivered today. Is there any lot code or other markings on these that could give us an idea if we might have gotten some from a bad product run? I am partial to my teeth and don't really want to use them for stopping should my front & rears go out.
 

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Same thing just happened to my rear pads, F0C3 (metal w/fins), that came with my XTR m988 brakes. Fortunately I had a 5 mile climb back to the car with little descending. Brakes are only 3 months old and there was very little wear on the pads. At the time of failure I was riding on flat terrain, it was not the direct result of heat from a long descent.
 

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I must be missing something... The friction material is still in contact with the rotor, no? The lock pin is in place, trapping all pieces in the caliper, no? The brakes, should still work, even if it's not "optimal".

I get the pissed off part, but how does this immediately translate into potential death scenario? I don't see how this failure translates to more than a new set of pads and a quality investigation within Shimano...?
 

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Hooligan
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I must be missing something... The friction material is still in contact with the rotor, no? The lock pin is in place, trapping all pieces in the caliper, no? The brakes, should still work, even if it's not "optimal".

I get the pissed off part, but how does this immediately translate into potential death scenario? I don't see how this failure translates to more than a new set of pads and a quality investigation within Shimano...?
look at the pictures - the braking material separates and falls off the rest of the pad. the heat sink and backing plate are still locked in, but the part that touches the rotor comes off and gets lost on the trail, leaving nothing contacting the rotor. pumping the brakes a few times might extend the piston enough to push that metal backing plate into the rotor, but that would likely do a lot of damage to the rotor.

sucks, because i really liked shimano brakes. i guess i will be waiting for a while to upgrade to xt's.
 

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The 'friction material' is brazed onto a backing with two 3 mm circles. The backing + friction material capture the heat sync between them. The failure mechanism is that the friction material fall off and is not captured in the caliper (mine is lost on a trail somewhere south of Mt Hood). So no contact is made with the rotor unless you pump the lever multiple times to enable the heat sync to contact the rotor.

The safety concern is pretty justified, I had no warning at all until I pulled the lever all the way into the bar with no contact.
 

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EAT MORE GRIME
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this is literally unbelievable that friction comes off the plate

friction has been glued to backing since time began and this is not rocket science in the slightest to make it work perfectly and in large batches. monster fail


so glad I saw this thread, I have 2 new bikes coming and both have shimano disc brake setups and this will be my first go at shimano discs...will obtain aftermarket pads immediately
 
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