Help! NH 3 point won't go down

tallyho8 · Aug 21, 2008

My Ford/New Holland 4610SU had been working perfectly all week and I finally got around to checking the hydraulic fluid in the rear axle. I got out my manual and removed the rear axle oil level plug and it was low so I raised the 3 point hitch per instructions and added 2 gallons of utf (it holds 12 gallons) until it reached the oil level plug. I replaced the plug and filler cap. I started my engine and lowered the 3 point then raised it and went to lower it again and it won't lower. It has my 8' flail mower attached so there is plenty of weight on the 3 point.

What happened? I checked my shop manual under troubleshooting and it lists lots of things to check if the 3 point won't go up but it has no list for if the 3 point won't go down.

Soundguy · Aug 21, 2008

My bet is there was alot of gunk in the sump, and pouring in 2g of oil stired it up, and a piece lodged int he unloading ( control ) valve.. perhaps the exhaust portion.. etc.

If this were a 4600 I'd ask if it had a remote ont he top cover or the blank 3x5 hyd plate.. if so.. you could loosen that plug onthe top blank plate and see if oil came out.. or not.. but I'm not familiar with the 4610..

is it at max lift? if not.. take it up and then see if it will drop... got an ASC valve? didya mess with it accidentally?

soundguy

bruceatlam · Aug 21, 2008

I just worked through a similar problem on my Kubota --- it may not help you at all, but it's a short thread to read through;

http://www.tractorbynet.com/forums/kubota-owning-operating/124896-b20-tph-stuck-fully-raised.html

tallyho8 · Aug 21, 2008

I don't have an ASC valve. It is at max lift. I did not mention that the first time I let the 3 point down after I added oil, it went down kind of fast so I turned the flow valve to slower and then the next time I tried to let it down it would not go down even if I moved the flow valve all the way to fast and then back and forth a few times. Could the flow valve be stuck shut?

I am afraid to try disconnecting things or loosening bolts, covers, etc because there has to be some very high pressure trapped in the system somewhere keeping my 1000 pound flail mower up in the air. If I loosen the wrong thing and release the pressure my flail mower will drop quick or some high pressure will make the loose part go boing and disappear and I don't want to get sprayed with any high pressure hydraulic oil.

bruceatlam · Aug 21, 2008

"Could the flow valve be stuck shut?"

I think that happened in my case --- don't know if you read thru the thread or not. I can't envision how it could happen, but just as soon as I started to remove the cap on the TPH cylinder(my flow valve is mounted through that cap), I think I freed something up and then when I opened the flow valve, the TPH started to lower. Go figure --- I can't. But, it works as it should now after its little "stuck" episode.

Can you get the mower off somehow?? Another tractor with a loader?? Block it up??

tallyho8 · Aug 21, 2008

I loosened a plug (31) on the accessory cover on the lift cover and let the fluid slowly flow out to allow my 3 point to go down so I could remove my flail mower. As soon as I started it afterward the 3 point went back up. I just moved the tractor down my driveway a short distance and it felt real hot by the flow control valve plate so I think the pump is building up a lot of pressure that is not being relieved some way and I better run my motor as little as possible while I diagnose my problem.

It's late now. I will try to find time to work on it a little tomorrow.

Eagleview · Aug 21, 2008

Do you have an obvious leak ? 2 gallons is a lot of oil to replenish . Are you sure it's not overfull ?

Soundguy · Aug 21, 2008

tallyho8 said:
I loosened a plug (31) on the accessory cover on the lift cover and let the fluid slowly flow out to allow my 3 point to go down so I could remove my flail mower. As soon as I started it afterward the 3 point went back up. I just moved the tractor down my driveway a short distance and it felt real hot by the flow control valve plate so I think the pump is building up a lot of pressure that is not being relieved some way and I better run my motor as little as possible while I diagnose my problem.

It's late now. I will try to find time to work on it a little tomorrow.

I think you need to check the exploded diagram on your unloading valve system and relief to study the oil flow circuit. If pressure was not being relieved.. a seal would blow.. or oring.. or shaft seal..etc..

if your 3pt control is down, and the lift goes up when you power it up.. unloading valve sounds stuck...

soundguy

tallyho8 · Aug 27, 2008

I finally got it working again today.

Thanks to everyone for giving me info on the repairs, especially, JC-jetro, who emailed me a lot of info and encouragement on trying the repairs myself.

I do not know exactly what was wrong but this is how I fixed it. I removed all the valves and plugs in my flow control plate, one at a time and let some fluid out of each one and worked the position control and flow control knobs as I was doing so. This included the flow control valve, oil cooler valve, check valve and miscellaneous plugs. I started my engine and worked the controls a few times and PRESTO it started working again. My next step is to change the hydraulic fluid (12 gallons) and filter to hopefully, prevent it from happening again.

Without the help from TBNers, my tractor would be in the shop and I would be looking at a >$1000 bill.

THANKS TO ALL!!!!!!!!!!!!!!!!!!!!!!!!

JC-jetro · Aug 27, 2008

tallyho8 said:
I finally got it working again today. Thanks to everyone for giving me info on the repairs, especially, JC-jetro, who emailed me a lot of info and encouragement on trying the repairs myself.

I do not know exactly what was wrong but this is how I fixed it. I removed all the valves and plugs in my flow control plate, one at a time and let some fluid out of each one and worked the position control and flow control knobs as I was doing so. This included the flow control valve, oil cooler valve, check valve and miscellaneous plugs. I started my engine and worked the controls a few times and PRESTO it started working again. My next step is to change the hydraulic fluid (12 gallons) and filter to hopefully, prevent it from happening again.

Without the help from TBNers, my tractor would be in the shop and I would be looking at a >$1000 bill.

THANKS TO ALL!!!!!!!!!!!!!!!!!!!!!!!!

Good job Dudley

Sweet.

Keep it up. You need Ford 134, TSC Mystick works just fine and it is not prohibitively expensive. you got to do both cleaning the inlet screen and replacing the cartridge filter.

JC

Soundguy · Aug 28, 2008

Check the oil canister.. if it meets the M2C134D.. I'd use it. Right now I'm using walmart supertech oil in my larger fords.. been fine for a few years now.

soundguy

tallyho8 · Sep 9, 2008

Drat! After using it a couple of times the 3 point hitch went up again and won't come back down. I repeated all the procedures I did the first time with no positive results plus I changed the oil and filter.

It looks like I am going to have to remove the lift cover assembly and start looking for the defect. In my manual it looks like most parts and valves are fairly easy to check except for the unloading valve which requires special tools for removal. I wonder if there is any way to see if the problem is in the unloading valve without removing it. Or if there is a way to backflush the valve in case it has some gunk in it.

Does anyone have a Ford manual that lists reasons why a hitch might not come down? Mine only lists reasons why it might not go up.

JC-jetro · Sep 10, 2008

tallyho8 said:
Drat! After using it a couple of times the 3 point hitch went up again and won't come back down. I repeated all the procedures I did the first time with no positive results plus I changed the oil and filter.

It looks like I am going to have to remove the lift cover assembly and start looking for the defect. In my manual it looks like most parts and valves are fairly easy to check except for the unloading valve which requires special tools for removal. I wonder if there is any way to see if the problem is in the unloading valve without removing it. Or if there is a way to backflush the valve in case it has some gunk in it.

Does anyone have a Ford manual that lists reasons why a hitch might not come down? Mine only lists reasons why it might not go up.

Hey Dudley,

Sorry to see you back in a pickle again

unfortunately I don't have shop manual for your tractor. The scaned pages that you sent me does not cover details well, I'll go ahead and read them again.. may be I can see something that I missed. After all the stuff yo have done it looks more and more that unloading valve may be the culprit. From the pics you sent me it does not appear that taking the top cover is difficult and at the least you'll need a come along and a tout tree branch or better an engine hoist to lift it. It'll be heavy and a finger pincher

if you don't have a right setup.

JC,

tallyho8 · Sep 10, 2008

I wish I had put this thread under New Holland or under Hydraulics and maybe I could get more responses.

Hi JC,
I just removed the lift cover using my Yanmar fel. Removing the cover was pretty easy. The worst problem I see so far is that it is too clean. This makes me suspect that it was removed and worked on recently before I bought the tractor. I would have preferred it to be dirty and full of gunk so I could at least know that everything was in factory installed condition.

I just came in to eat lunch after having a quick look inside so I am typing this up while my hands are clean before I take anymore apart. After studying up on it as much as possible I suspect the control valve or the unloading valve as Soundguy suggested. The control valve appears to close by gravity only and not by direct linkage and I have to inspect that more to see if it could be sticking open. Most likely it is the unloading valve and this is the most difficult one to get to and check. I do not have the recommended slide hammer and adaptor to remove the end plugs and do not know if I can rig a wheel puller to do this task.

I was hoping I could get by with just cleaning something and not needing to buy parts which will probably take some time to get and I want to get my tractor back together before it storms tomorrow.

As I said before it is very clean inside so it may not be something stuck with crud but I do not believe that any part is broken since it works sometimes and stops working other times as if something was sticking.

I'm going back to work on it now.........

tallyho8 · Sep 10, 2008

It's fixed.

My control valve was sticking open. The spring could not even push it closed. I removed the spool from the bushing and rubbed the tight part with some 1500 grit sandpaper and cleaned out the bushing well, oiled it up and put the spool back in. It has just the right amount of drag now that I am sure it will work correctly and it slides open and closed very easily.

Since I had never worked on hydraulics before I was very leery about taking it apart even though my manual had basic instructions. But I found that the hydraulics in this tractor are pretty basic and anyone with a little mechanical aptitude can figure most of it out. Now I feel like I know a lot more about hydraulics and maybe I can even give someone some pointers in the future. If JC hadn't given me the incentive to start on it I probably would have spent a fortune at the shop getting it repaired.

Other than oil and a filter and some permatex I didn't have to buy any parts but I did get some clothes pretty greasy.

Now maybe I can cut the weeds in my back pasture and see if the bermuda has time to grow back before the first cold front hits.

JC-jetro · Sep 10, 2008

tallyho8 said:
It's fixed. My control valve was stickilng open. The spring could not even push it closed. I removed the spool from the bushing and rubbed the tight part with some 1500 grit sandpaper and cleaned out the bushing well, oiled it up and put the spool back in. It has just the right amount of drag now that I am sure it will work correctly and it slides open and closed very easily.

Since I had never worked on hydraulics before I was very leery about taking it apart even though my manual had basic instructions. But I found that the hydraulics in this tractor are pretty basic and anyone with a little mechanical aptitude can figure most of it out. Now I feel like I know a lot more about hydraulics and maybe I can even give someone some pointers in the future. If JC hadn't given me the incentive to start on it I probably would have spent a fortune at the shop getting it repaired.

Other than oil and a filter and some permatex I didn't have to buy any parts but I did get some clothes pretty greasy.

Now maybe I can cut the weeds in my back pasture and see if the bermuda has time to grow back before the first cold front hits.

Dudley,

That's great .. good news... I was kind of upset that original effort did not come to full fruition. No matter still all good effort. you just got to break it down to smaller components to analyze and fix. As they say, it's better to learn how to fish rather than getting a fish, I just turned the saying a bit to match the situation

I was planning to read your diagrams tonight for bed time reading but you beat me to it.

JC,

tallyho8 · Sep 10, 2008

One of the things I was happiest about was that I did not drain my 12 gallons of hydraulic fluid. There is no way I could drain it and keep it clean enough to reuse and it was brand new.

To remove the parts I removed, my manual says step 1: drain oil. I couldn't figure out why I should drain the oil as I was taking the top off the rear hydraulics and the oil level is a foot below where I was working. Glad I didn't follow that part of the instructions.