300 U Hydraulic pump rebuild. Re installed but no hydrau

Got the pump back together. Turning the shaft was difficult but as predicted it began turning more easily and smoothly after several revolutions.

Reinstalled the pump (see pic). I was concerned whether the rectangular lug in the pump I Sharpie marked during disassembly would align correctly in slot the lug fits into coming off the distrubutor and then correctly mesh with the gear in the engine so the timing wouldn't be screwed up. That must have worked well because I was able to start using the hand crank rather quickly.
Unfortunately, I have no hydraulics. I ran it about 5 minutes and tried working steering and front and back remotes. Shut it down,checked hytran levels. Tried running it again, same thing still no hydraulics.
Before I tried starting the first time I did fill both lines that run from the reservoir to the pump with hytran. (They were already disconnected at the reservoir). I also tried removing the hex plug on top of the pump to fill with oil. It wouldn't budge. I gave it a few shots of PB blaster on 2 different occasions. Still very stuck and now it also stripped. Not happy about that.
The pump isn't making any noise and there are no leaks (maybe because there's no pressure??). The hydraulics worked very well prior to rebuilding the pump.
What do you think is the issue? Thanks for the help. Paul

I see the outer line to the pump is a hose with a fitting that can be loosened is the same true of the other line to the pump? I am sure you know which is the pressure and suction. Ideally if the the outside is the pressure here is what I would do. Take it off and cap or plug the hose, just a plastic cap or cork will work. Now apply air pressure to the fill port if you have a regulator you could set to 10 psi would be great or just a rag wrapped around an air blower and some common sense. Pull the coil wire out of the the distributor then pressurize the reservoir and crank the engine with 3-5 second intervals. Hopefully this will force oil down and through the pump to prime it. Personally I would have stuck the pump in a bucket of hydraulic fluid and turned it by hand to make sure it pumped prior to install. Sorry for not making that recommendation in one of my earlier replies.

Put 10 PSI in the reservoir under the seat through the Vent's Threaded hole. Run it. and move steering and fast hitch. Front wheels in a ditch also helps. Jim

I would disconnect that 1 suction hose and hold it straight up and fill it with oil and have someone crank tractor over , or just start and stop it. Even if you have to have a funnel in the hose end. Got to prime the pump with oil. Even if you dumped some gear oil in the hose.

Thank you Jim, Rust red and Used red. I added some air pressure and it worked like a charm. Hydraulics came to life almost immediately.

I cut grass for about 90 minutes and no leak at the tach. Unfortunately I think it's still leaking into the engine. I drained some oil before mowing today because, due to the leaking seal, the oil level was reading way above full. I drained it to about a half quart low. After I was finished the oil level had risen. It was not above full but it did appear to go up. I'm n hoping it's because the tractor may have been sitting at a different angle but I'm not sure how much of a difference that would make. I'll be keeping a close eye on it and consider whether it makes sense to change the rear seal again or am I just wasting time.
The help is appreciated. Paul

Yippeee!! I knew it would go well. If you decide to change the seal at the cam gear end, it can be replaced without even taking the hoses off (with a little bit of care and bungies to hold things. The seal can be pulled out of the housing with screws. Finding different seals from Motion Industries or Kaman Bearing that are thinner in cross section might allow 2 to be placed, with different wear positions. Putting grease or petroleum jelly between the two makes sure the outer one gets lube. Jim

Yippee is right Jim. Would have loved 100% A.OK but I'm pleased that what was literally a steady stream of hytran is no longer pouring out of my tractor.
I think other guys rebuilt entire tractors in the time it took me to do this pump!! Whethe the it holds or not, the process had lots of good lessons for this rookie. Thanks for sharing the knowledge and patience. If the internal leak is occurring I will follow up on the thinner seal recommendation. Best part is I actually understand what you are saying!! Paul.

Yippee X2 Jim