Rear brake bleeding issue
 

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.

did you start bleeding them from the back and working your way forward?
I think the order is left rear, right rear LSPV etc..if you did it in some random order you are gonna get air in the lines.

i have always had someone pump the pedal for me. Never had an issue with bleeding brakes doing it this way in almost 35 years of working on miscellaneous junk cars i have owned.

Yep, that’s the order except lspv last as it’s the highest point in the system. I tried the rear to front variant as well with no change. It’s either the lspv or master at this point. I’m going to pull the lspv and try again. If that works I’ll install a manual proportioning valve and be done with it. Thanks.