Have bleed system but struggling to get them any sharper.
Do any of you know the correct procedure or had any experiences with these?

Dead easy usually. Just push fluid up from bottom with syringe and watch bubbles emerge in little cup thing at top.

Make sure lever is higher than caliper.

Are you using proper Shimano fluid or cheapo mineral?

Juicy lube mineral, wouldn’t call it cheap!
Calipers was lower than lever and pushing fluid through.
Not sure about the “free stroke” screw should this be in or screwed out? 😕

Out, it increases the capacity of the master cylinder so you get a drop more fluid into the system. Then when you have finished bleeding you can screw it in and it actually does something.

Interesting and timely thread 🙂

I have just ordered an M820 lever to use with an M810 caliper.

I have syringes, whats this cup thing you talk about ? Will I need it to bleed them ? Or can I just suck a bit out of the reservoir as I push fluid up ?

Bazzer: it’s not essential but it makes life easy and is cheap. http://www.chainreactioncycles.com/shimano-bleed-kit-m575/rp-prod34710

bren: Allegedly Shimano mineral oil is slightly thicker than other mineral and does make a difference. I dunno how much internerd myth vs truth vs marketing rubbish this is though!