I bleed my brakes today with water for the first time, it worked ok until I got to step 4, I pumped the lever for ages but couldn’t get the brakes to bleed. Thinking about it! I realised that water was pumping in and out of the master cylinder without filling the brake lines and slave cylinders. I found the best way to fill the system without any air bubbles was to hold the master cylinder (handle bar lever) above the bucket of water (slave cylinders submerged with no bleed screw) and to pull the lever and hold it in, next seal the bleed hole with a finger (obviously with the bleed screw removed) and then quickly release the lever, this sucks up water through the slave cylinder with my finger acting as a non return valve. This routine was repeated until I could see plenty of water coming out of the master cylinder, when this occurred I quickly put the master cylinder under water, gave it a few more pumps and then installed the bleed screws. By the way I mixed the water with 25% of antifreeze so that the cylinders wouldn't corrode, I used an antifreeze that didn't contain methanol or ethylene glycol as these are very poisonous. Cheers Mad Dan