M785 XT brakes – got a problem preventing bleeding

Quick sanity check before I resort to sending back under warranty.

I have the correct kit and have bled these before on other bikes without any problem at all but I’m now having difficulty with one specific lever assy.
This is the first time I’ve tried to bleed this one unit.
When trying to bleed bottom-up, I can’t get fluid to flow back into the lever assy.
If I unbolt the hose from the lever, I can bleed to that point, so I know it’s within the lever that the problem resides.
I can’t get fluid in top-down either, through neither funnel nor syringe.
It’s as though there is a blockage between the master cylinder and it’s reservoir.

Anybody else experienced this?

I haven’t yet checked if the free-stroke adjuster has any impact but I’ve never adjusted that anyway.

Ideas?

free stroke out?

let it bleed from reservoir or funnel out down through hose gravity fed.
until the funnel is down enough for full bleed,.
then do up hose bolt

usual lever squeezing and tipping it back and forth till no bubble and done

No, I’ve not touched the free-stroke adjuster.

Can’t get fluid to run from reservoir into master cylinder. Will free-stroke adjuster effect this?

Update.
Resolved.
Yes the free stroke adjuster was the key to this.
For some reason, if it’s too far in, the master cylinder appears to be isolated from its reservoir, hence being unable to reverse bleed.
Wound it out and could then bleed as normal. Strange design quirk if you ask me 😕

Hmm, I’ve had similar on an SLX lever… will have to check the free-stroke blanking screw.

similar is you need to do a lever change and bleed through on older ones too. If the piston gets stuck too far in you cant get fluid down. the free stroke adjuster does a similar thing but allows you to manually pull the piston out a bit. 🙂

Accidental post