No fluid from nipple

[avinitboys]

Just started sorting the brakes after a long rebuild but cant get any fliud to push through the front master cylinder. I have had everything apart to paint, new seals and pistons in the calipers, new Hell lines front and rear, but didn't touch the master cylinder. I have tried all the usual methods even trying to force fliud round the system with a syringe, creating a vacuum etc. I managed to get fluid to travel from one caliper nipple out of the other so the banjos are ok and in place. Had the resovoir off to check flow to the master and thats ok too.
Could it be the master cylinder itself needing seals etc. It was fine before I removed it and I dont recall pushing any compressed air through it when cleaning and painting but I suppose it may be possible that I have dislodged the seals somehow.
Ant ideas guys?

[fastdruid]

I've had issues before with bubbles in the line between res and M/C preventing any fluid filling the system.

The way I do it now is to fill the caliper with fluid, push the pistons back in, then leave overnight with the res full and the tube vertical and the lever tied, then bleed as normal. You can keep pumping the lever which gets a smidge of fluid in every pump but easier to leave overnight!

Druid

[Neosophist]

If you get a syringe, the sort you use for cooking will do, attatch a rubber tube and suck the fluid though the nipple to start it off!