Air in power steering.

[grubsster]

I finally had the opportunity to install power steering to my '66 which went well using. Captain Fabs bracket. However, I can not get the air out of the system. We did the cold bleed without engine running while still on the lift no wheels on the ground. After that we started the truck still off the ground and tried a few lock to lock turns and the pump continued to make noise so we shut off the truck. Foaming fluid shot out of the cap. Let it sit overnighpart tried again this morning to no avail. Decided maybe the rebuilt pump I had installed could be bad so bought another with the same results. We are keeping fluid in the pump at all times. The only used part is the gearbox, so long story long, can the gearbox be bad and cause air buildup in the system?