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In my efforts to push back in the Pistons on my shimano caliper I have pushed them all the way out and one has leaked a bit of fluid. Is this terminal or can I retrieve the situation with a good bleed?
Will probably need to replace the seals.
That sounds like a new caliper to me, as you can probably tell in the way I got into this situation, I am far from a bike mechanic
Will probably need to replace the seals.
Which I believe you can't get for Shimano.
May as well give it a bleed and see. Otherwise you can buy a new caliper.
It's quite unlikely that the seals will be have been affected at this point. The piston will/should just go back in, though you'll need to open the lever (valve or cap) too. I'd recommend making sure to clean the pistons first to ensure you're not pushing grime into the seal. Wet the sides of the piston with some brake fluid to aid insertion and pay close attention to pushing the piston in perfectly square - a thumb on opposite sides and pinch inwards gently at first. It may need a good squeeze to get the piston beyond the seal at first, but don't be too shy so long as the piston isn't visibly twisted.
Brake fluid is going to leak from both ends while you're doing this and, you're right, you'll need to bleed afterwards.
Push em back in and give it a bleed.Unless you damage the piston when pushing them back in there's no harm done.
And don't see any reason why you'd need new seals.
As above - I've pushed mine out deliberately when I needed to clean them. I put a smidge of silicone grease on the seals - which may or may not be a good idea in terms of compatibility with seal or fluid, but helps the pistons to move smoothy and hasn't caused any problems.
I don't understand why Shimano won't sell seals, but they don't, and I haven't found anyone else selling replacements.
I put a smidge of silicone grease on the seals - which may or may not be a good idea in terms of compatibility with seal or fluid, but helps the pistons to move smoothy and hasn't caused any problems.
Fine with DOT; possibly not with mineral oil - is my understanding.
I've done this (to the point of leaking not falling out). Pushed them back in eventually - a flat tyre lever right through and pulled from both ends worked well for me - and then just cleaned up the caliper and checked for leaks by putting the bleed blocks back in and squeezing hard!
Should be fine, unlikely to have done any damage to the seals.
Almost certainly will be fine- just clean and carefully replace the piston, don't get it in squint, don't force it.
Well that was a bit of a job in the end. Had to take the whole caliper apart and get the unit in a vice and apply significant pressure to the Pistons to get them to return. Got it sorted eventually and today have bled and fitted new pads, working like a good un now 🙂