i feel its a bit of a hit or miss. sometimes i can get it, sometimes i can't.
I've never been able to get a gravity bleed a bike before. Starting a new dry system is always the toughest. What you need to do is get the nipple loose, just finger tight. Then you need to pump up the lever and open the nipple with your fingers. You need a lot of pumps to build up air pressure in the line, before cracking the banjo each time. When you crack it, you should give it a few seconds and also wiggle the nipple and wait for the air to come out. The reason you use your fingers is because you have to crack that nipple open a ton of times before the fluid will even start to flow, so its much faster than using a wrench.funny i was thinking you should try voodoo, then you mentioned black art, i read this thread hoping there would be some info on here for me. I just started trying to put fluid in my new system today all day long i've had an open reservoir full of fluid connected to a brembo lever with it's bleeder valve open and braided steel lines with calipers with open bleed valves and hoses attached, nothin,, tommorrow i clean out my fork fluid syringe and try pulling fluid by vacuum from the calipers bleed lines. I'll take any lever feel though firm is prefered ,all my experience is with prefilled bicycle hydrolics,hayes and hope tech.Monday i call spires were i bought my perhaps a bit outdated brembo(non folding) lever and brakel lines/pads at pretty much top dollar, right now i got a bit of buyers remorse, though i would be instantly psyched if i can this stuff to work.
Have you tried tieing up the brake lever? sometimes that helps to make the fluid flow through the mc better.whenever I try that, some fluid drains out of the caliper body but doesn't pull down more fluid from the lines, and I get a huge air bubble.