LS Tractor Hydrolic Filter Change

Using a vacuum to put negative pressure on the transmission reservoir while changing the hydro filter. This prevented the hydro oil from draining out while swapping the filter. This worked great with one exception:
After all done, fluid level checked, I started the tractor and had no pressure on anything. No power steering, couldn't move the loader up or tilt my grapple, grapple would not open or close, and box blade would not go up.
I tried moving the loader control around to get the fluid moving. Had the motor RPM up a bit, tried steering back n forth. Nothing to get the hydro pressure up. I only tried this for a few minutes.
I figured there was air in the lines from sucking the fluid back into the reservoir. I got the targon tubing used on the vacuum and fitted a smaller hose inside. Shoved my air nozzle into the smaller hose, then pressurized the reservoir with about 60 PSI. then removed the pressure. Turned on the tractor and still no hydro pressure. Tried again to pressurize the hydro reservoir with the tractor running this time. held it for about a minute. Popped the hose off and air came wooshing out of the reservoir. reinstalled the dip stick, got in the tractor and was able to move the loader up and down. Steering and box blade moved good too. I moved all control surfaces for several minutes to be sure there were no air in the lines. All seemed good.
I am assuming that pressurizing the hydro reservoir pushed fluid back into the lines. Also, it did take me a while to change out the filter. Maybe this wouldn't have happened if I had installed the filter quickly.
Anyone else's constructive 2 cents?

[@glenstull6351]

Do you ever need to change the fluid?

[@OGAlJerom]

Nice 👍

[@thooper4380]

Cool trick. I'm about to do mine on the same exact tractor, but hydrostatic transmission. Where did you get the 1" tube and how are you refilling the reservoir with hydraulic fluid? I've got a 5 gallon bucket of it and I'm thinking a funnel, but might end up spilling more than I get in there.