Brake pressure problems Advice please

[whippit]

I bought a 91 300zx sis months ago and have been working on fixing it up. I recently replaced the aluminum front calipers with the iron calipers to stop warping rotors. While I was replacing the calipers I allowed the brake system to gravity bleed. Now I can not get brake pressure. I have bleed all lines on the calipers along with the ABS module at the passenger front tire. After that I replaced the master cylinder, but still no luck. If I pump the brakes I get pressure but then after 10 seconds it will go to the floor again. I have even used a vacum bleeder for the top bleeder valves on the abs module behind the passenger seat. Any help would be appreciated, I love my Z and hate having it sitting on a rack.Hoyt Robison

[WidebodyZ]

Sounds like you're going about bleeding it all the wrong way? I personally have only bled the brakes through the calipers themselves. In most cases just manually with the help of a friend. I never touched any of the ABS componants. Make sure to check for any leaks..your symptoms don't make sense to me...you may have introduced more air to the sytem fi you didn't keep filling the brake fluid while trying to bleed them.