A while back I replaced both brake lines running to the rear LSPV. I had no braking issues prior to this, one line had corroded through and began leaking so I replaced both along with the fuel line.

I bled the master, all wheel cylinders/calipers and LSPV, in that order multiple times. After the better part of a quart of brake fluid I still get air from the rear brake cylinders...and I mean tons of air...it looks like aerated clean fluid. The front calipers and LSPV produce a steady stream of bubble free clear fluid. I can drive the truck but of course the braking is very poor and spongy.

Not sure it matters but I work solo so I always use a pressure bleeder attached to the master cylinder. With 10-15 psi behind the reservoir I can't sort out how air can get in to the system, when I have a leak is see it immediately as fluid exits. Where/how is the air getting in this system? And only the rear cylinders? LSPV? Master? I'm at a loss.

Thanks, S.