3-Point Hitch 3 Point linkage won't lift weight

[ajess33]

Our YTO 180 compact won't lift implements etc. There is plenty of fluid . Power steering appears fine. I want to follow system from oil to pump to see if the fluid is going to the right places. A list of do's and don'ts will help. Could there be air in the pipes and if so how can this be bled.
Any help would be welcome
Thanks
Alan UK

 

[Artisan]

Are you revving it up a bit or trying to do it at idle?

 

[ajess33]

Hi
Thanks for replying. Both really. If you rev it it seems to try and lift but I don't think the pressure is there.
We that tried a hydraulic log splitter connected via a flow and return. This is slow and when the ram meets the log it stops( zero power) and then the arms go up then drops like a stone. Its weird

 

[RonMar]

If you have supply and return quick connect ports on the back, these are probably in parallel with the 3PH cylinder. Did you have to raise the 3PH control lever to send fluid to the rear quick connects and log splitter? IF so, the fluid takes the path of least resistance(splitter cylinder) untill a load is encounterted, then it takes the other path thru the 3PH lift cylinder. Now if that cylinder is leaking, the fluid now takes that route. Is there a 3PH speed reg valve in front of the seat? If you close that you should prevent fluid from flowing into the 3PH lift cylinder, which will force all the fluid to go out thru the rear quick connect to the splitter. Try closing that, then retry the splitter to see if it will develop any power. It is probably a 4" cylinder, so it will be slow with the onboard pump, but when it comes up against a load it should make great power if the pump is OK. IF it does not, it could be a pump, or it could be a pressure regulator valve problem.

Do you have a loader on this tractor? The loader has a PRV, depending on how the system is plummed, that could be relieving prematurely, but if the loader is lifting fine, it is probably working OK. The 3PH control valve also has a PRV that could be leaking and preventing the 3PH from developing any lift...

 

[ajess33]

Hi Ron. Thank you for taking the time to explain everything. I will have a look tomorrow and get back with an update. There is no loader just the power steering the flow and return quick couple valves at the rear and the 3ph. Is there a method of eliminating or finding problems from the feed to the pump and from the pump to the steering etc. I don't want to undo something and make things worse.
Cheers
Alan

 

[greg_g]

A pressure gauge would help. But short of that, I recommend you start with a visual inspection of the pump. I'm not familiar with the YTO, but will assume that it uses the standard CBN-type pump. If so, the pump has a square drive tang that fits into a square receptacle in the gear drive housing. Disconnect the pump from the housing and inspect both the tang and the receptacle. If one or both have been rounded off, the pump tang is slipping - and little or no pressure is being developed.

//greg//

 

[RonMar]

Well if there were a problem with the suction side, the steering would probly be choppy/pulse while you turn the wheel as the air bubbles pass thru the valve and cylinder. If the power steering is functional and has smooth power, and it is a single hydraulic system, then the supply and pump are probably OK. Is there a block with 3 lines connected to the pump outlet? One line comming from the pump, one running back to the 3PH and the third running to the rotary vane pump/valve at the base of the steering column. If so, and I suspect you do, that is a diverter valve that gives the steering priority over the 3PH when you turn the wheel. Again, if the steering is functioning good, that diverter is probably OK also. The difference between good and bad steering function can be demonstrated by turning the steering wheel with the engine shut off, and seeing how difficult that is to do. It works, but it isn't easy.

What usually happens in these machines is the 3PH piston seal fails, and the fluid just runs past the piston instead of lifting the impliment. A pressure gauge plugged into that quick conect at the rear of the tractor(they are at the rear of the tractor right?) would tell you the actual pressure being applied, but a log splitter doing some work and splitting a log can also show you if any usefull pressure is being generated, at least for troubleshooting purposes.

That speed regulator valve in front of the seat is really valuable at this point, as closing it/screwing it all the way in should take the 3PH lift cylinder, and it's possible blown seal out of the equation. When you close it, the 3PH lift arms shouldn't go up when you try and cycle the logsplitter. If it is a blown piston seal, closing that valve should deliver full splitting power to the logsplitter. If you still don't have full logsplitter power, then the problem is not the 3PH cylinder.