Clutch systems can be tough to get started because there is no residual valve to help the pumping action. Pressure bleeding or vacuum bleeding works best. Gravity will often do the job in a clutch system, as Luke suggests.
Luke is thinking that the rubber cup may be blocking the inlet port. If you could get any pressure at all, it would either move the cup or leak around it, but until there's enough fluid in the system to build up a little pressure you wouldn't get movement or a leak, so Luke could be right. Be sure that the linkage is adjusted properly and not holding the piston and cup tight against the bottom of the bore.
If you can get any fluid at all out of the bleeder, the inlet port is open at least a little. Try putting a plastic hose on the bleeder nipple and sucking on it, watching carefully to be sure you don't have sudden success and get a mouthful of brake fluid. (Ptui)
If that doesn't work, disconnect the line at the slave and see if you can get fluid to flow. If you can get the line bled, hook it up again and try the cylinder.
With this particular master cylinder, you could do a crude version of pressure bleeding with just shop air. Remove the holddown bolt from the lid and wrap a towel around the lid and cylinder leaving access to the bolt hole. Hold the lid down as hard as you can and, with the bleeder open, use a blow gun to put air into the bolt hole. You should be able to get maybe 10 lbs of pressure before it pushes the lid up harder than you can hold it down, and that should be enough to get the fluid moving.
Joe
