3 point hitch

[Rich07]

I have a foton 254, it went into the shop for a new clutch, I used it a couple of weeks ago and found that the 3 point hitch would not drop. I adjusted the knob under the drivers seat, got covered in hydraulic fluid, and it dropped the hitch. I used it again today and again it won't drop the 3 point hitch. The knob hasn't been touched since last time. Any ideas what may be wrong?

 

[Fawken]

Well, for starters it sounds like you have a hydraulic leak in your flow control valve. The position control valve may be stuck wide open sending too much pressure into the cylinder. Start at the position control valve would be my first check, but have never worked on a Foton.

 

[greg_g]

The knob under the driver seat is in fact the flow control valve. But there's no legitimate reason for it to have screwed up during a clutch job. That said you may have a diverter valve in the wrong position. How many hydraulic remote fittings are behind the driver seat?

//greg//

 

[D0TC0M]

@OP,

Did the hitch work at all after you had the clutch work?
Did it work and gradually stop working?
Does it work when cold?
Do you have a load on the hitch when trying to lower it?
Does it creep up with the lever in neutral position?
Was there a lot of pressure when you removed the flow control valve or was it only coming out under the weight of the hitch?

Things to check,
Make sure your mechanic installed the vent port on the hydraulic tank/sump and confirm it isn't bocked off. If its good then answer the following.

When you had lowered the hitch and restarted the engine with the lever in the neutral position, does the 3 point hitch hold its position or does it creep up to its maximum upper mechanical limit?

If it creeps up - Check the valve pack that the up/down lever is connected to. I'm thinking that when in the neutral position that control valve is passing.

If it can maintain position in neutral - then I would suspect you got some crap in the flow control valve under the seat and its plugged.

But there's no legitimate reason for it to have screwed up during a clutch job.

Your right although I presume they would have drained the sump at one point to separate the engine from the tranny. Its possible that by emptying the sump they either could have stirred up some crap sitting on the bottom of the sump or inadvertently let something get in the system OR they might have accidentally blocked off the sump vent thus letting the sump build up with pressure as the temperature of the liquid rises and preventing the hitch cylinder from venting to atmospheric pressure.

 

[Rich07]

This is my first tractor so please forgive my ignorance, I purchased it used and there is no Foton dealer locally.

There was a lot of pressure when I removed the flow control valve, I had dropped the bush hog off it before unscrewing it. The hitch held steady once I hooked it up again, but when I raised it, it would not come back down even with the weight of the bush hog on it.

When I tried loosening the flow control valve the nut that attaches it the tractor turned, should the handle turn independently of the nut or is this normal?

The vent is not blocked as hydraulic fluid was pushed out it over the back end of the tractor.

 

[D0TC0M]

The handle #5 should turn with the nut #2 that is normal. There should be a little setscrew (#12) preventing the handle from unscrewing off completely. I suspect you have a problem in the flow control valve but its also problem you could still have a problem with the 3 point hitch diverter assembly. In either event you will most likely need to drain the tank of hydraulic fluid and start disassembling with the flow control valve which looks to be the easiest IMO

 

[greg_g]

There was a lot of pressure when I removed the flow control valve, I had dropped the bush hog off it before unscrewing it. The hitch held steady once I hooked it up again, but when I raised it, it would not come back down even with the weight of the bush hog on it.

When I tried loosening the flow control valve the nut that attaches it the tractor turned, should the handle turn independently of the nut or is this normal?

Ok, I'm getting it now. The flow control valve is closed, and the knob is spinning on the shaft. You probably broke the set screw free or rounded off some edges trying to force it. The reason it won't move is the weight on the lift arms. it's trying to push fluid back into the sump, but it cannot because the flow valve is closed. Put a jack under the mower, and lift it so all the downward pressure is off the arms. At that point you should be able to turn/open the flow control valve. Then let down slowly on the jack to get the mower to the ground. You should do this with the engine running, so the pump can properly circulate the returning fluid. Once the mower is on the ground, shut off the engine - let the fluid settle for a few minutes - check the level, add fluid as required. Then go about repairing any damage you did to the flow control knob - replace if necessary. This should get you back to ground zero to see if further troubleshooting may be necessary.

//greg//

 

[andre12a]

Hi

I realise this is an old post but I have the same problem with my D254 and I'm wondering how this was fixed. I have read that air in the lines or some foreign object could cause this problem. Someone said that by fully winding in and out the adjustment has repaired the problem. Any thoughts if anyone is still reading this. Cheers. Peter.

 

[D0TC0M]

Air in the system will not prevent it from lowering but a foreign object could certainly cause this.

 

[andre12a]

Thanks for your response. How large would that object need to be. I have a problem with and o ring breaking down at the controller and I suspect that parts of it may have broken off into the fluid.
cheers
Peter