Appreciate your thoughts...
Neighbours lad is very keen to do his own maintenance...
However, during his bleeding, he has managed to blow the seals out on 2 XT brake levers.
Not sure if they are M8000 or M8100.
Apparently bleeding from caliper up using syringe and cup on bleed port on lever. Seal is the one outboard from the bleed port. Mineral oil over the wall type eruption...apparently after gently pulling lever back...
I have not observed him doing the bleeding, but never seen such a thing myself.
Any thoughts?
My thoughts, bled with worn pads, allowing pistons to come out further than intended, bleed screw refitted, then levered the caliper pistons back, and the pressure from the excess fluid has blown out the diaphragm. I can't really see many other ways of generating the sort of pressure it'd take to blow seals like that, though nothing that people inflict on their bikes surprises me any more.
Think it's new lever time sadly, not sure they make rebuild kits for Shimano brakes do they?
coatesy
Free MemberMy thoughts, bled with worn pads, allowing pistons to come out further than intended, bleed screw refitted, then levered the caliper pistons back, and the pressure from the excess fluid has blown out the diaphragm. I can’t really see many other ways of generating the sort of pressure it’d take to blow seals like that, though nothing that people inflict on their bikes surprises me any more.
This was my thinking too, but I've had that issue in the past (when being lazy) and it was fine to use afterwards. The OP makes me think he's (the lad) already replaced the lever and done it again?
The new "vent thingy" seems to actually reseal I thought I'd wrecked a new lever but cleaned everything up and it's still in use.
Yeah, as above - lever can pee out fluid if bleeding a bit forcefully, a bit alarming but hasn't caused an issue.