Dan, as I'm following you all's advice, I'm getting you want me to get pressure readings from the FEL valve PB and remote valve PB. I'll get those pressures later this morning.
Thanks for the explanation about how the reverse flow can be happening. Yes, it's only with the "control screw/diverter/spool" in the horizontal position. I found that out yesterday when I collected 4 gallons from the FEL valve inlet port. I understand that for loader or remote operation the "control screw" needs to be in the vertical position. I only switched to horizontal to isolate the 3PH, and diagnose why it wasn't working. I have verified the hose configuration multiple times because I understand I could have made a simple mistake. I wouldn't ask for help on a forum, if I hadn't already done my diligence.
I've been using a cloth to filter those 4 gallons back into a container to bring the tank level back into the sight glass for testing today.
Yes, the big question is: Why is there flow with pressure, but the loader and 3PH don't move?
My issues started with water contaminated fluid, a bad FEL valve float detent, and oil leakage from the quick disconnects. ...but it was working. I already had parts and seals for the HUSCO valve, so I removed it, cleaned it, and disassembled it. When I got to the bare valve block, I sprayed degreaser into the bores, rotated it, dunked it into hot soapy water, then I sprayed brake cleaner into the bores. The brake cleaner came off the block clean, so I called it good. Honestly, I didn't inspect the bores after the brake cleaner. The spools didn't show any scratches, chips, and wear marks. I reassembled with light swipes of vaseline, and everything went back together normally.
I'm going to finish filtering the oil for reuse, and get those PB pressures. Thanks!
