I believe John is correct, the secret for the pedal is to get all the air out ( as always ). On our 2020 Plus Six the ABS acuator block is located under the near side wing, near the windscreen washer bottle and the swirl pot. The actuator blocks on some cars and bikes can sometimes be tricky to purge of air.. I have a hand held vacuum pump designed to pull the fluid and air through the system from the bleed point, works far better than the standard up/down of the foot pedal method. Just have to make sure someone is at the master cylinder topping up the reservoir, because it sure pulls the fluid though quickly.
The best method I have found is to use a combination of a positive pressure bleeder and pumping the pedal. I have a Sealey bleeder and it's got a ginormous tank on it so no worry about running the Master cylinder down. Pressurise it up to its operating pressure and then open each nipple in turn whilst my glamorous assistant pumps the pedal in a series of rapid moves. The reason this works well is that often you can get small bubble caught in odd nooks and crannies which a constant pressure won't shift as the flow rate is still low. Add the pumping though and the additional jerk will tend to move things along nicely.
I learned this some years ago when I first got the bleeder. On my first attempt I must have put 2 litres of fluid through the system but still some annoying sponginess. I went to ask my friendly local garage for advice and they put me on to the combination method. Works brilliantly and you can bleed out an entire system in a few minutes. It does depend on having a glamorous assistant to hand though. Fortunately mine is easily bribed with promises of chocolate.
