I'd only do the caliper that isn't working.

Using the 2 man method get someone to pump the pedal a few times then hold the pressure on the pedal whilst releasing the bleed nipple. When the pedal sinks to the floor, lock off the bleed nipple and then your assistant can let the pedal rise. Repeat this process about 3 times.

Do each nipple on on the caliper like this seperatly.

Appologies if you know all that - but it will be useful for others.