Compact 990 Hydraulic issues

[danabcraig]

I have a 2007 990 compact tractor and the hydraulic system is driving me crazy. It was working fine then started getting jerky and then quit. I've lost all both steering and other functions. When I checked the screen was clogged so I replaced the screen, filter and new hydraulic fluid. It still didn't work, It appears to be starvine for fluid at the pumps so I primed them, it worked until it used up the prime. Checked/replaced all of the rubber hoses as I found one was cracked. Then in desperation I replaced both pump and still it doesn't work. Cleaned the filter housing and made sure it wasn't clogged.
I'm at a loss on what to do. I got the hydraulic fluid from Tractor Supply, I thought it said J20 compatible, could this be the issue?

 

[bmaverick]

J20C marked on the TSC Universal hydrostatic fluid should be fine.

Is there air trapped in the system?