MegaSack DRAW - This year's winner is user - rgwb
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I’ve just had to replace the front callipers on two bikes running XT M8120 4 pot brakes.
The small pistons had cracked on both bikes. Probably my fault moving the pads apart.
Has anyone else had any cracked pistons on theirs?
Nope but good heads up.
Where on earth did you get replacements? I was convinced I got the last 2 7120's in Europe.
All the European shops seem to have stock and it’s cheaper than the UK.
All the European shops seem to have stock
Ah, must be the 7120's.... I was kicking myself for not buying earlier when they were decently priced at €55 then everywhere just seemed out of stock in either pads so I did the email alerts.. I'm still waiting for then found 2 at Tweeks but ended up paying £60 each which is exorbitant but as my 2014/5 calipers seem to be starting to fail (2 in last 3 mo) I figured I'd stick on 4 pot instead.
Probably my fault moving the pads apart.
Are they ceramic pistons? If so, did you push the pistons back in with the pads in or out? Ceramic pistons are best pushed back in with the pads in as opposed to a screwdriver etc to prevent damage.
Its quite common for ceramic pistons to crack when they're forced back out of line with a metal implement like a big screw driver or a spanner.
Its quite common for ceramic pistons to crack when they’re forced back out of line with a metal implement like a big screw driver or a spanner.
I've done this dozens of times on 2 pots... more times than seems like "good luck"?
I had this happen when I squeezed the lever quite hard whilst bleeding the brakes. Got the whole brake replaced under warranty, it happens a lot more than it should apparently
I always use a plastic tyre lever when pushing pistons back in
I always use a plastic tyre lever when pushing pistons back in
I heard people say this but what is the purpose on ceramic pistons?
OK, so feel like a complete idiot but how on earth do you get the 2nd piston out?
Pulled apart a M785 and a bit of bleed pipe between the bleed valve and pump with my thumb over popped one out but how did anyone get the other out?
Ah... so put them back together ...
1) If you get frustrated and keep jamming a spanner in to prevent one side it will crack the ceramic...
So took apart again
2) If you get the right size tube you can fire the other side out but don't fire this at grade 4 ceramic tiles...