Adapter to use MTB bleding kit funnels (M5) on Shimano road levers (M7)

thingiverse

Use MTB bleed kits to bleed road levers. Print in whatever material and whatever precision give you a suitably well-formed threads, preferably in some material that is much softer than the material of the Shimano road levers. Install a 1.5mm thick O-ring (or whatever else you have that will seal) on the M7 side. Don't overtighten. If you do and break the top off, you should be able to remove the lower bit with a 3mm hex key.