The problem with that is if there are air bubbles trying to go up and fluid trying to go down they can interfere with each other.
If it would gravity bleed, it would bleed through normal bleeding procedures.
That's my outlook on it anyway, but who knows when it actually comes down to it.
That's why I have multiple ways of bleeding depending on the circumstances.
The Ford Ranger with the hydraulic clutch was one that didn't like to bleed normally because the air would go up in the line while we were bleeding fluid going down.
It was WAY easier to push the air up than down.
