Oliver 1650 loader won't lower

Hello there
Just registered
I have an Oliver 1650 Wheatland style/no 3 point gas powered with a loader
was recently using the loader to lift 1200lb (just a guess) and it can lift the weight without issue
The problem I'm having is with the loader at 3/4 height and starting to lower it down it just stopped and would not lower
I curled the forks and dropped the load. Still won't lower so I ended up cracking the line and bleeding it down
After some research it seemed like maybe the couplers could cause this flow restriction in one direction New Pioneer couplers same issue
Today I took the valves out and disassembled the left hand valve. I see no broken springs, plungers, dirt, issues at all
The loader was lifting and curling still just will not lower when it usually has downforce
Sorry for the long post but I'm just not understanding what happened or how to proceed from here
Also it had some chatter when lowering heavy loads and was smooth empty
Thanks in advance Dave

Are they one way or two way cylinders? If they're one way, it's likely that you're pumping all the oil out of the reservoir and don't have any pressure to release the valve to let it down.

To my knowledge (limited) they are dual acting valves and cylinders
I usually have lifting force as well as enough downforce to lift front wheels off the ground
Even after bleeding it down to lower loader to the ground and replacing the couplers to that valve and topping system up when it was raised a couple of feet only still no response in the lowering position of the valve not slowly lowering nothing at all but has pressure at the coupler and cracking the fitting is the only way to set loader on the ground so can relieve pressure in the line
Dave

We had one at the farm did the same thing. Took out the couplers and replaced with pipe unions. Because this loader was never removed that was a good repair. After examining the couplers we found small bits of rubber lodged in the couplers. This can happen when the lining in old hoses start flaking apart internally. If you see any sign of this be sure to replace the the hose and filter.

My niece's husband bought a 1650 a few weeks ago. He got it home and hooked on to the disc. It wouldn't lift it. He tried the plow. The 3pt lifted the front, but the remotes wouldn't lift the tail wheel. He tried the 1850 and that lifted both. He put new couplers on it and that took care of it.

Maybe a dumb question but is the loader running off the remotes or power beyond with its own valve.

Another dumb question- but what's the fluid level? Just want to make sure you're not losing fluid into the rear end.

fluid level is full on the dipstick
I check it often as the old girl leaks a bit from everywhere
I haven't had it that long and it didn't run when I got it but I've pressure washed the dirt and buildup from leaks off and am starting to repair as I go. This tractor is only used for lifting and has 5 foot forks on it
As of yesterday I've changed the couplers ( no power beyond ) That had no effect except they don't seep
I bought a pair of fitting yesterday and am going to plumb it without couplers ( off chance issue is still there with new pioneers)
I have removed the valve stack and disassembled the stack as well as the left valve. With the left valve completely apart I can see no reason for it to not work. Nothing cracked or binding scored. I bought some new o rings (the large ones with metal insert ring and will swap the valves left to right and see if this is the issue. Was curious about what valving makes it so this style hydraulic system you can't bump the levers and release the pressure (safety feature) but the machine has to be running to get any response from the controls. am I missing some other place the issue could be lurking? This is a learn as I go process but it seems this will have a fairly simple solution just what/where should I look next? Thanks to all forum members for all the help Dave

Under the seat and to the rear on each side, there are two flat head screws that have a lock nut on them. I don't remember which one, but I think it's the one that screws in to a big nut, not the one that goes directly in the casting, loosen the lock nut and turn that screw out about three turns. Do that on whichever side you have the loader boom plugged in to. If it doesn't help, turn it back in and try the other one. I couldn't get the markers down on the planter with my 1850 and when I turned that screw out, it worked.

He has a 1650 Wheatland, thus no 3 point, so it may be located differently. Agco has changed their web site so can't look at the parts books without going through a dealer, at least i can't.GRUMBLE-GRUMBLE.

You made me curious, so I tried. A box came up over the screen that said this OR click here to visit agcopartsbooks.com for your
parts catalog information. I did and the box went away so I had the option of using my account or entering as a guest. I clicked
Guest and it worked for me.

My bad, after digging more I was able to get on, but the fine print say's only good until May something.

I thought somebody said the web address changed. Maybe that box only redirects you and after that date you'll have to use the correct address or something. I guess we'll find out.