3PH won't raise after interferemce with Draw bar

[Paddy]

I did a wrong. I lent my friend my tractor and set him up with the box blade. I forgot to take off the draw bar and there was interference. When I came back to get it, draw bar was bent and the 3PH did not lift. He showed me he could get it to lift by bumping the FEL joy stick. Bump the FEL joy stick and it raises every time. Lowering, no problem. I'm guessing he used it for 10 hrs under this condition. I have replaced the 3PH presure relief valve with no change. Now I thinking the gasket/rings on the lift cylinder is damaged. I have changed the Hydro oil and cleaned the filter. The draft linkage was a bit loose but played with it and it too made no change other than not working at all when adj to one extream.

Any ideas?

 

[slowrev]

Loaning stuff out is often times rewarded in pain....
Oh well, does the loader work ok, still strong. Just wondering if the pressure relief valve could be stuck ?

 

[Timber]

Oh man does that just stink, I have people say that is a nice tractor, I usualy say I know were you can get 1 just like it. So dose he go the other way when he sees you now

 

[jinman]

Sounds like a stuck spool valve or something in the diverter that works when it gets shocked by a surge in hydraulic pressure. It just doesn't sound like a leak to me. You didn't mention which tractor...Kubota or Kama? I'm assuming the Kama since it seems to be your newest tractor.

 

[Paddy]

As stated, I replaced the PR valve but no change. I disconnected the FEL from the Hydro circuit not only it won't raise but I don't have the little trick of bumping the joy stick. This is on my KAMA 454.

I have continued to use the tractor, the FEL and 3PH have all the power they did before. As the oil was drained, I was able to look around in the case. All looked fine. As I operated the draft and the raise lever, I could see that a cam pushes in a plunger. I assume this is the lift valve. The plunger went in and out smoothly.

Thanks for your help, it's sure stupming me

 

[Soundguy]

This reminds me of a hyd problem I had on my NH 7610s. One remote would not work, the other was fine. I found if I engaged the non op remote, then engaged the operable remote, the inop one would presurize as long as the operating one was presurized.. but as soon as the good one was centered, the inop one would bleed off, unless you centered it. As far as I can tell it was a non repairable flaw in the remote pack.. perhaps a pilot and or check valve..

Sounds like the oil to your 3pt is not getting there unless another circuit is bumped..

Whats the plumbing sequence?

Soundguy

 

[Paddy]

SoundGuy,

When the FEL is completely removed from the circuit, I have nothing. Because the FEL is there I can bump/pulse the circuit and get it to go. If I don't bump and hold, the FEL will operate but the 3PH will not raise untill I let go. So this is oposite your condition. All I have to do is a small and quick pulse on the joy stick and up she comes.

I belive the FEL is first in line from the Hydro pump and is returned via the FEL joy stick open center control to 3PH lift box.

I took the lift box cover off today to observe the oil while running. With the engine running and lift lever down, some turbulance can be seen. Bump the Joy stick of the FEL and faithfullly the 3PH raises and the turbalance stops while it raises. Turbalance resumes whem max height is reached. Now I tried to use the lift lever without the bump of the FEL trick, turbulance but half as much.

Maybe the lift valve??

 

[Brad_Blazer]

Paddy,
In my parts manual the "Distributor Assemblyly" (sic) contains 5 valves: the main valve, safety valve, oil return valve, lower valve, and check valve. I'm not sure of the function of the last 3 valves since I don't have a schematic but they all look like check or relief valves. The behavior you describe sounds like a check valve that is not seating. Maybe the loader actuation is sharp enough to force the valve to seat where the 3ph valve (main valve) is more gentle. Of couse the check valve spring is supposed to keep it seated all the time.
I'm guessing here but the "check valve" and "lower valve" are perpindicular to the "main valve" and pointing at the main valve channel so they might interact. Those might be worth checking out first.

Since my Kama is nearly the same as yours I am interested in your problem and would like to see some pictures of the inside of your lift box.

Best regards,
Brad

 

[Soundguy]

I'm thinking like Brad. And actually Paddy, the situation is not 'opposite' of what I observed.. just different. In both cases, we have a dead circuit that can be made operational with coop use of another circuit. In myy case, the pilot only worked while there was constant pressure from the other remote, to make the pilot operate, then supply oil to the non op remote. in your case, it seems as if the momentary flow bump front he loader is causing another valve or check to temporarilly operate correctly, and then it returns to no operative condition afterwards. Similar.. but not opposite.

If you have a hyd schematic.. post it.. it may be easy to determine from the info we have.. after looking at the valving.

I'm most familiar with unloading type valve systems.. but lookinh at in's and out's may give us a clue.

Soundguy

 

[Paddy]

Brad,

The KAMA 454 and 554 are nearly identical except your engine has one more cyclinder. I have some photos but not sure they show much. I will re-size and post.

SoundGuy,

I don't have a Hydro schematic, I can describe the routing of the pump, aux, FEL and lift sequence. It would be nice to see the schematic of the Lift valve and how relate to each other. I think we all feel this is the area of issue. With 5 safety/check/PR/main valves it might be hard to isolate what O-ring or spring is failing to seat untill the serge of presure. I can buy the entire valve assembly for a decent price. New valve might be the best plan and re-condition all valves on the old one for a spare in case I manage to repeat this bone head stunt!