Originally Posted by
fietsbob
Consider this : Take the caliper off The Frame, so you can hold it higher than the master cylinder-brake lever , to do as Francis suggests ..
Take the Brake Pads out first so oil overflow wont contaminate the Friction Material ..
NO -- do not do this.
You have reasonable assurnace that whatever air is there is near the top of the system, near the brake lever. Bubbles move very slowly in narrow hydraulic lines so if you invert the system it will be hours, days, or even weeks until the bubbles move to the caliper. This is fine if you plan to flush the line and replace the fluid, but not for a simple weep and bleed.
Instead, either "burp" the system via the reservoir,
see video, or bleed it by cracking the fitting at the lever end. In short, to bleed air you have to work where the air is, or at least close enough that you won't be pumping all the fluid out before reaching the bubble.