I know this is an 8N forum but wondering if anyone here has any knowledge on 1000 series tractors? I have a 74 3000 gas with an engine mounted hydraulic pump. Last year I had the engine rebuilt. Had a bad cam so they replaced that an also put new rings, bearing act. to it. Got it back in August and used it to mow a few times. 3 point was a little slow but worked fine. Seemed to get better as tractor warmed up. I put the back blade on and graded my stone driveway and put it in the barn. Getting it ready for snow that is coming and now 3 point will not go up at all. I bled it at the pump as the manual says and it worked ok Thought maybe it had gotten air in somehow. Now it doesn't work at all. I put a ball valve in at the pump bleeder and hooked up a clear plastic line to run the fluid back into the fill hole in the rear. Air bubbles are in with the fluid. Must be sucking air from somewhere. Also I did put new and proper fluid into it before I had engine repaired. My thinking on his is that when they split the tractor for engine repair they did not get the seal on the suction line at the pump. I could be wrong though as I am quite often ha. Any ideas? Whatever I have to do is going to wait till spring. Barn is unheated and it is really getting cold. Storm coming they are saying. I'm hoping my Polaris and plow can clear the driveway since tractor is now working. Thanks for any ideas.

They can be a real pia to bleed.
The suction tube to the pump on those just pushes in to an oring on both ends.
Splitting the tractor requires you unplug that tube
from the pump. When I remove the pump one of those I use some lacquer thinner on a rag and Clean both the tube and port it plugs in to. Then I use a TINY bit of silicone and wipe it around the tube before I push it back in.
That usually does the job.
They can still be a bear to bleed but you are doing it right by running a hose back to the fill hole.

More than once, after using silicone as described above, I have gotten frustrated by one not bleeding so I took a long drive on the tractor just to calm down. Magically the 3 point started working again and it worked ever after.

PS, slow 3 point can be adjusted with the flow control valve on the right side below the draft/position lever.
Screw the knob in for faster hydraulics. Out for slower.
I have never needed to adjust the lift speed so just screw the knob all the way in and leave it there.

Thanks for the info. I'm thinking that the pump is shot. I got it to work by bleeding and parking it with he front end lower into a ditch. 3 point started working fine. I figured I had it fixed. Drove it around the farm for about 30 minutes running the lift up and down. Next day it will not go up at all. When I open the bleeder nothing comes out. Pump must not be pumping anything.

I took the chuck out of the hole where you check to see if it's full and blew some compressed air in. Seems to be working fine now. I had my brother unscrew the bleeder on the pump and we got a bunch of air to come out. It lifted my blade up and down really quick. I'm hoping it holds. Thanks for your information.