94 4runner sr5 3.0 5spd 4x4 298k miles Had to replace both rear axle bearings and seals recently. Had axles out for several days. Used rubber vacuum cap over brake lines during that time. After putting it all back together I have no fluid to rear wheel cylinders when attempting to bleed them. Tried letting it gravity bleed for a bit too and nothing. Master cylinder never got below the add line. Fired it up and brake warning light is on. Did some research which lead to possible load sensing porportioning valve issue? A mechanic buddy of mine mentioned master cylinder could have bad seals and wont pump up rear circuit after pressure was released. Brake pedal doesn't go all.the way to the floor but is definitely softer than before. Just trying to get a few educated opinions on where to look next. Thanks

Make sure the rear shoes are adjusted properly, and you need to bleed that lspv.

From the link below: The proper order for bleeding the system is to start with the longest hydraulic line and work around the vehicle to the shortest line, and then do the LSPV last. So in this case, the order is: driver's rear wheel, passenger rear wheel, passenger front, driver's front, LSPV."

Check this link, helpful break stuff: Care and Bleeding of Your Brake System.

I did bleed the porportioning valve. Still no fluid moving to the rear wheel cylinders. Bled the front as well. There was some air in there in the front and at the valve. Still no flow at the rear cylinders. Also opened the line coming from the valve to the rear circuit. It was also dry. So looking like something wrong with either the valve or master cylinder? Also the wheel cylinders and rear shoes were replaced about a year and a half ago and are adjusted