So I noticed, when changing my pads, that a crack has formed in the calliper piston on my rear brake, as shown in the image above. The brake is a Shimano M615 brake and is a little over 1.25 years old.

Is this OK to ride with? I went out a couple of nights ago and, while I thought braking was a little weak, I did survive.

I think the brake has a 2 year warranty on it, so I may look at that.

On another note; how does this happen? I’ve not abused the brake as far as I’m aware.

Most certainly.

I would take it back if it’s under warranty unless you can’t be bothered in which case just buy another…..I wouldn’t personally trust it not to give out and loose all the fluid in one go…….extreme heat and corrosion? Pistons being pushed back with pokey stick when they were already jammed?

i’d take it back and try warranty- failing that just buy a replacement calliper- at least it will come with new pads.

I can’t see how anything that you could have done would cause that (except maybe forcing back a really siezed piston). It looks like the crack has been there for some time, so I would suspect a manufacturing defect.

I wouldn’t ride with it.
I would ask for a warranty replacement, or an explanation of how the damage has been caused.

Really hard to see how that could be anything but a manufacturing defect tbh. 10p says effortless warranty job. Actually double or nothing, why not, I bet they give you a whole new brake.

It probably is safe but you’d feel a right knob if it explodes and kills you

Cheers guys. I’ve contacted CRC and going to see what they say; they’ve been excellent in the past, but these were gifted to me so I dunno how they’ll handle that.

They a look pretty corroded for a sub 2 year old brake – have you been riding through a lot of salt? Could corrosion be the problem?

thats what i thought .

those look horrendous – and thats before the crack.

Also – no you wont die (Yawn)
…and I would ride it until my new parts turned up