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I have a zee calliper (2020) on an xt 8000 lever and hose from 2014 ish. Working fine until I broke the bike down into parts a few months ago. When I went to refit to another bike the lever had packed in and the piston wouldn’t return.
Thankfully a friend had a set of the xt8000 brakes in his spares bin and gave me them. Quick check and they seemed to work fine
I swapped his lever for my broken one and all seemed good after a bleed.
I then needed to remove and refit the lever to fit the cable through my triple crown forks and the brake stopped working.
When I pull the lever it Bites and all 4 pistons move but then the lever still pulls to the bar. I’ve bled it again twice and searched for leaks but can’t find anything. Also checked the lever connection and olive are fitted properly.
Any idea’s
Bled shimano brakes a lot for fairly confident in my bleed technique
Cheers
James
Air in it somewhere
Air in it somewhere
Indeed, but when you pull the lever you pressurize the system. Any leaks would have leakage of fluid.
Which brings you to bad bleed or failed master piston - seal is adequate for lowish pressure, bit crank it on with a good squeeze and then fluid bypasses the primary piston seal and fills the reservoir again.
Yep, either air in system or failed master cylinder.
You could try the Marshy bleed technique to try and eliminate any air, I think he completely removes the bleed nipple from the caliper and gravity bleeds it. Could you also bleed it with a smaller bleed block to get a bit more fluid in the system?
Thanks for all your replies
Tried the marshy bleed and pushed pistons out and back again as part of he bleed process
I suspect failed master cylinder
Doesn’t feel spongey like air in the system, resistance builds up until the pistons contact the bleed block and bite then resistance disappears and the lever pulls to the bar. It feels like fluid should be squirting out of the system but can’t find that anywhere
I’ve got one more spare lever albeit RH not LH but I’ll put that one on tonight as a test to see if it works
Worth a try in both stuck piston and leaking master cylinder levers?