What can cause

[Bouncer]

A brake pedal to go to the floor, you've still got a brake bit hardly any, if you pump it you get some pressure again not much....master, slave (if there is one) or pipes

[Jay762]

Air in the system. Bleeding them should sort that out.

 

However check for leaks, these could be with the calipers, any joint in the system or the master cylinder

[Bouncer]

Thanks, will have a look tomorrow

[Miggs]

Does sound like air in the pipes, I've had a split pipe and that gives a touch of brakes then the pedal continues down and the brakes slowly release with the foot to the floor, I've had air in the system too and this was pedal to the floor first press but as you pump the pedal it gets better till you can stop, I'd get the car up and if possible all wheels off and get someone pumping the pedal while you walk/crawl round and see if you can see any leaking fluid or bubbles