Yanmar 240 Loader Hydraulic issue

[jb92563]

I was using the loader on my Yanmar 240 and a had just raised the bucket and dumped the load and suddenly the bucket controls ceased working with the bucket in a raised position.

I can not raise or lower the bucket or move the wrist, not even under its own weight to lower.

I checked the hydraulic oil reservior and it may have gone below the hydraulic pumps pickup.

I added oil and still nothing is working.

Is it possible to loose hydraulic oil prime in the pump?

There is an oil filter at the controls that I will check.

I am not familiar with the Hydraulics so I am not sure where to check.

Perhaps there is something in the controls that needs cleaning.

Its odd that the failure was so sudden and complete, which leads me to believe that perhaps something is stuck in the controls, even though I am able to operate the levers without any noticeable change.

The aux hydraulic loader pump that operates off the front of the engine seems to be turning fine so its not the engine coupling.

How should I go about debugging this?

 

[Soundguy]

bottom line, even if you had removed the hyd pump.. the loader should LOWER under gravity pressure when you open the dump port.

thus it has to be a valving failure or oil stoppage, or mechanical hangup.

if you have any quick disconnects, and one of them came loose, that COULD be the issue.

next, make sure the loader control linkage really is moving the spool in the hyd valve.

lastly.. look for something mechanical that could be hanging the loader up.

my bet is option 1 or 2 vs 3

 

[jb92563]

I'm thinking the valving/blockage too as normally the bucket will lower on its own in a day or two and so far it has not budged an inch after 2 days.

Thanks for the suggestion. Not being familiar with tractor Hydraulics yet I was not sure where to start.

 

[284 International]

There is a key on the shaft of the pump. This can wear or fall out, and will let the chain coupling spin normally but not power the pump. There is a hex drive set screw that is supposed to remove all the slack and locate the shaft, but that can loosen too.

I would look there first, because the "suddenly quit working" portion is a clue that something immediately changed, rather than the typical gradual weakening/slowing of a clog.

If you look very closely you will be able to see the actual shaft of the pump. Make sure that is turning when under power; as an aside be very careful crawling around or just generally being near or especially under the elevated bucket. Entropy suggests it will, eventually, fall...at whatever rate. Watch out for kids/pets/careless people doing the same.

 

[winston1]

It should lower whether the pump is working or not. Any change in sound when moving the lift lever or curl lever with engine running?

 

[clemsonfor]

Yea if no fluid or working pump it would lower when the valve was opened.

And unless you lost all your fluid you cant go below the pickup..its basically the bottom of the sump.

I think you have a stuck valve in the control. i would remove it and take it apart, looking for trash to clog passeges or seize the control.

 

[Leejohn]

You should block that loader somehow or bleed it down.

 

[jb92563]

Yea if no fluid or working pump it would lower when the valve was opened.

And unless you lost all your fluid you cant go below the pickup..its basically the bottom of the sump.

I think you have a stuck valve in the control. i would remove it and take it apart, looking for trash to clog passeges or seize the control.

I can move the control levers as normal so when you say stuck valve, isn't the valve directly connected to the lever, and hence you can "feel" if it was stuck?

Also, I lost both functions at once which seems logical if they are in series and something got plugged upstream.

The not leaking down as normal is perplexing and I wonder if that indicates anything.

 

[jb92563]

It should lower whether the pump is working or not. Any change in sound when moving the lift lever or curl lever with engine running?

No change in sound when operating the levers so it seems its not getting fluid movement at all.

 

[jb92563]

There is a key on the shaft of the pump. This can wear or fall out, and will let the chain coupling spin normally but not power the pump. There is a hex drive set screw that is supposed to remove all the slack and locate the shaft, but that can loosen too.

I would look there first, because the "suddenly quit working" portion is a clue that something immediately changed, rather than the typical gradual weakening/slowing of a clog.

If you look very closely you will be able to see the actual shaft of the pump. Make sure that is turning when under power; as an aside be very careful crawling around or just generally being near or especially under the elevated bucket. Entropy suggests it will, eventually, fall...at whatever rate. Watch out for kids/pets/careless people doing the same.

I was looking at the chain coupling that was turning but could not see if the pump shaft itself was turning, dark, obstructed and dirty area. Perhaps a shot of dayglo orange to that area would help.

I'll have to take a closer look as that could explain the situation except for the lack of the usual leak-down after a couple days.