bleeding rear brake

Hi all
Just thought I'd post this ; My rear brake has done nothing for ages (loads of travel would'nt even stop bike gently rolling down hill in neutral, non ABS 2011 base model)
Anyway MOT time so had to sort it somehow.
Fitted HH pads changed fluid to Halfords racing dot 4 and attempted to bleed. Removed caliper and raised as high as possible got a little bit of air out of bleed nipple after 3 complete flushes but no more after using 2/thirds of the bottle ,still loads of travel no real brake action. After lots of head scratching noticed a bubble trapped in reservoir hose feed to master cylinder.


Enter my brother (vehicle/plant fitter of 49 years experiance) who suggested a different approach. Put caliper on floor, pumped pistons out as far as we dare (about 6mm on each piston) then pushed them back all the way with a flat bar. This pushed loads of air back into the reservoir (several large bubbles) repeated this process several times until no more air appeared. Wow! almost no travel the best its ever felt and it actually attempts to stop the bike! the rear brake passed the MOT without a mention. We do not understand the logic of this as you'd think conventional bleeding would push air through the master cylinder. Dont know if this is a permanent fix but hope it helps somebody in similar position.