So I did the conversion from the power master to vacuum brakes. Everything went well and I'm confident that I've got everything bled out. By confident i mean i went around the whole car probably four times to make sure there is no more air left in the system. I also replaced the rear brake shoes along with rear wheel cylinders and got everything adjusted properly. The problem I'm having now is that i have really good front brakes but hardly any rear brakes. I feel like i have a proportioning valve problem but I'm not entirely sure. Just wondering if i should have changed the proportioning valve when i did the vacuum converion, just because of the different brake systems and maybe the difference between the power master and vacuum brakes require a different proportioning valve. Or would that original valve work fine with the vacuum brakes and i just have a faulty valve? If anyone has any info at all on my situtation I'd appriciate any advice.