question 3320 Hydraulics-What goes up won't go down

I recently bought a Zetor 3320, sorted out a few bugs (steering and brakes) and all seemed well. Took it out to try and do some roto-tilling and it was doing good. However halfway down the row the 3 point hitch went up and will not go down. I did not touch anything or make any adjustments before it happened. The oil was a little milky, I have since replaced it with utf and a new filter. There was a lot of dirt and metal shavings on the magnet and screen.
It sounds like the relief valve is running all the time which according to a previous post indicates a stuck valve. How do I find out which one and where it would be.
Any suggestions will be gratefully received.

Hi, sorry to hear of your troubles, I have no answers for you, would be interested if you know this model of tractor gives much trouble, I was planning on looking at one shortly, and am a little concerned to hear your issues, I never came across a tractor lift that would not go down, usually they won't go up or stay up.
Milky oil does not sound good, indicates water got in at some point, is there a cab on your tractor.

Is there a Zetor dealer locally, you could phone them and ask about your situation, a lot of dealers will be happy to provide information as you will most likely buy the parts to repair off them, lots of dealers are too busy and will avoid a lot of time consuming jobs that are difficult to justify charging a customer for, and are happy enough to guide you through resolving your issues.
Just curious to know if your hydraulic pump is on the outside of the tractor and bolted onto the side of the engine up near the front, of if it is inside the back end, some here have it on the side while some in the back end, just wondering if there is a patter of problems associated with either internal or external pump models.
What do you mean by UTF oil, I thought it would either be gear oil or an engine oil such as super universal tractor oil (SUTO) that went in these tractors.
Given there are metal shavings in the tractor, I would not be happy until I took the top cover off and inspected the damage, shavings are not good, and something in there needs repaired.
For example, if it was a simple sticking valve and you replaced it, how long would things keep going with shavings causing damage to the new part, and any other parts they come in contact with.
In any event, I hope someone comes along with more helpful information.

Regards & good luck, J

If the 3pt is overloaded, the valve can get stuck due to overheating oil causing it to expand in its bore. Popping the clutch to wheelie it ( making the implement hit the ground) will take the oilpressure off for a moment, usually unsticking the valve.

Thanks so much for the help. The tractor is at a different location so I have not tried the ideas yet. It may well be that I have to pull the cover off but trying to avoid it if I can. The UTF is universal tractor/transmission/hydraulic fluid from tractor supply. I think it calls for 80w gear oil, but I thought the thinner oil would help flush it out. Maybe I shouldn't do that, please let me know.
I spoke with some friends familiar with hydraulics and they said there is a rod that triggers the 3 pt hitch to lift when in draft mode. Maybe that had become disconnected.
Anyway I will try popping the clutch to see if that will do it. Hope so. Thanks again.

I appreciate the help, tried popping the clutch and still not working. Probably going to have to take the cover off and see if I can see what is going on. Any suggestions on that project would be helpful
On the bright side I managed to brush hog some grass that we are going to bale for hay. Tractor ran well, I used the ground speed pto and hydraulics off setting. Will use the same tractor to rake and bale within the next few days.
I know you are supposed to use a hay mower for mowing hay, but I don't have one. I do have a brush hog so that's why I did it.

Thought you might like an update on the Hydraulics. I finally got the seat off and the top of the differential removed. I am not exactly sure what was wrong. A clip and a very small pin had fallen out of one of the linkages we found the pin and put it back in with a new clip. When I changed the hydraulic filter the original clip was in there.
However it almost seems like the part that attaches to the top link and causes the draft control to lift when needed had got stuck.
It popped back so quick when we moved it that we couldn't tell if it was stuck or not.
I was also having trouble with the brakes, I added more fluid and it disappeared in a few days. I added more again and it is still full.
Brakes seem to work now.
Thanks to everyone for their help.

I was also having trouble with the brakes, I added more fluid and it disappeared in a few days. I added more again and it is still full.Brakes seem to work now.

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Its strange that all fluid disappeared and now they are working because it sounds like the tractor has a leak and if seals are gone or got stuck it`s not going to get better