Can someone link me to one please for the 2 piston ,not the 4?
Not the banjo one.
You mean the one off the bleed nipple (Tries to think of another one...).
The one that goes between the two halves of the calliper when you take it to bits.
The one that goes between the two halves of the calliper when you take it to bits.
I assume this is the one which is supposed to cause the micro-leaking?
"I assume this is the one which is supposed to cause the micro-leaking "
That's the one.
is it the bit circled in blue here
It might be the same, but that diagram doesn't show the two calliper halves apart, with an O ring in between.
https://www.ebay.co.uk/itm/141455807147 is mentioned on this thread https://singletrackmag.com/forum/topic/leaking-shimano-calipers-possible-solution/
If you stick "shimano seals" into ebay there are now kits for sale (obviously more expensive than buying 50 o rings)
Interestingly there are finally aftermarket piston seals for sale, rather than just the aftermarket piston and seal kits. Also aftermarket master cylinder seals, pistons and dust boots.
Might be time to fix some Shimano brakes. Not sure if it would be cost effective as a chargeable job v new, but given parts availability it might be an option.
The one that goes between the two halves of the calliper when you take it to bits.
3mm ID x 1.5mm section is what has been recommended (to replace the 3mm x 1.3 original).
I used a 3.1mm x 1.6 section one from an Aldi/Lidl selection box and it seems to have worked.
(The rear brake of my fat bike started squealing on a regular basis - cured by cleaning & baking the pads, but it kept coming back. I was highly sceptical, but tried this as a last resort. I think part of the problem, at least was that the hole in my calipers was significantly off centre wrt the O-ring recess - in fact I'm surprised it ever sealed.
I also added some sealant between the two halves (Loctite 542 FWIW) and the brake has behaved itself since.)
