I set about putting my 312s on the other day, only to find the thread which the bleed nipple screws into had been cross threaded, meaning the bleed nipple got stuck in and couldn't be closed properly, but that's not the main problem.

I've put the standards back on, there's new fluid in the reservoir and it has been bled. Despite this, the brake pedal doesn't have any bite until you press it hard down. Can anyone shed some light on why and how I could resolve it/what to look for?

Thanks

i would say theres still air in there somewhere, did the calipers get completely drained when taken off, ive heard they can be a pain in the arse to rebleed.

They lost a bit of fluid but it didn't get completely drained. The res is full of fluid as well. I bled until no more small air bubbles came out