I have a 70 ElCamino that I just replaced the master cylinder, since I would start losing the pedal at stop lights. I also put on new front pads while I was at it. Everything was fine until I started bleeding the brakes. I could not get any fluid to come out of the front passenger side. Ended up taking off the caliper (Fluid came running out of the brake line just fine so I replaced the caliper) I am still not getting any fluid out of the bleeder. I have tried putting a vacumm pump on the bleeder and still nothing. Any suggestions on what it could be?