Formula Oro K24 bleeding(?) problems

Hi guys,

I need a bit of help to sort my K24s out, as I am really struggling to troubleshoot what the source of the problem is and I'm hoping somebody can shed some light on the matter.

The problem started was when I started to lose feeling in my rear brake, when they would start firm but seem to lose pressure after repeated lever pulls. I figured that they at least needed a bleed so that was the first thing I did, however I then struggled to achieve a good bleed and only managed to make things worse. I've replaced the master cylinder seals and the reservoir too, as they seemed a bit worn.

I have found it impossible to bleed them successfully as (following the proper method) when I go to bleed the calliper (with the brake lever fixed/master cylinder closed) the syringe seems to fill with air endlessly. I can only assume that there is a leak somewhere near and that air is being pulled in from outside rather than from the fluid.

If I force fluid into the calliper I can't see any obvious massive leak. 2 areas that seem to look wet with fluid are the edges of the pistons and the banjo bolt. I've replaced the piston seals - but not the pistons themselves.

Any ideas where the leak could be coming from? Do the pistons wear down, as well as the seals? Do banjo fittings fail? The next things I could replace is the pistons and then the copper washers/banjo bolt. I'm just guessing though. I dont want to keep replacing things for no reason as its getting expensive!

Any help most appreciated...

David