I’ve discovered the master cylinder of a Shimano Deore hydraulic lever is blocked somewhere… It’s not pushing oil down to the caliper (I’ve checked both the caliper and hose are open by blowing through them). Disconnecting the hose from the cylinder and pumping the lever results in nothing even though the reservoir is full…

Any tips for cleaning the MC out?

If it’s like pretty much every other brake in existence, you should be able to get the master cylinder out just by removing a small circlip where the plunger from the lever goes in. I’d start with that they just make sure everything is clear before re-assembling

That’s what I feared – these are flippy levers and the circlip/plunger are pretty recessed. I can’t seem to remove the lever to get down there. If anyone knows a way to clear it without removing the circlip I’d love to know!

Cool, that’s fixed it. Cheers matey!