FEL hydraulic issue when raising boom

[Fishingfoolemjak]

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[Dave M7040]

When raising the FEL at idle, I can pull the remote joystick back pretty much all the way till it stops and still get the boom to raise. The FEL has a slow and fast boom raise mode based on how far you pull the joystick back.

However, when running the engine at higher RPM, and thus when hydraulic pump output is stronger, the only way I can get the boom to raise is to pull back on the joystick ever so slightly - if I pull back just a bit too far (what my hand is trained to do after 5 years of loader work on this machine), the loader stops raising, like it's going into bypass mode up at maximum boom height. The only way to re-set, and get the raise function to work again, is to quickly push forward to float mode, then go back to raise mode. Simply releasing the joystick back to neutral position does not re-set the lift function. Loader work has become a huge hassle. Every other loader hydraulic function is fine. I have tried switching hydraulic hoses around, and the problem seems to stay at that same port coming out of the loader valve (moving to the new hose/function plugged into the apparent problematic port).

Am I going to need to pull the loader valve apart and possibly replace the internals on the boom side, or is there some sort of simple hydraulic bypass adjustment on the loader valve that needs to be made? It is a remote (wired) joystick from the cab to the loader valve, LA403 loader on Kubota B3000 Cab model. I have confirmed the joystick adjustment (am able to use the joystick lock feature).

Any suggestions? Thanks in advance.

I have posted on this thread already but am starting over with new information from CROSS HYDRAULICS

Your description of how you had to get your loader arms to lift puzzled me. Pulling back a tiny bit instead of all the way.

I started to wonder of someone had swapped the IN and power beyond ports on your FEL valve block.

Plse see the question I asked CROSS hydraulics and their answer.

POWER BEYOND AND IN LINES SWAPPED

My question:

If the IN port and POWER BEYOND port are reversed as a FEL valve is connected into an existing hydraulic circuit on a farm tractor, will it still operate properly?

Stated a different way, the high pressure line from the tractor痴 only hydraulic pump is connected into the FEL痴 POWER BEYOND port instead of the IN port will it still operate properly?

REPLY FROM CROSS HYDRAULICS

Good day! No, it will not operate properly. When the spool is shifted the Power Byd is blocked.

Thanks, Jeff

The relevance to your situation is that when these two hoses are reversed, the power beyond port is very quickly cut off as you move the spool which sounds exactly what your FEL is doing.

Dave M7040

 

[Leejohn]

oldnslo Roy you said the loader would not lift in regen. That was driving crazy wondering why. I know he said all the hoses were right and etc.
Well today I tried it, putting the A & B hoses on each spool the same as the other. A to C and B to D, C went to A and C went B. Bucket worked just like the boom,, also had slow dump (float). Now the boom would lift just that it would lift in either bucket down or bucket up. The boom was lifting both don't quit understand that part. The only way the boom would down was to go past detent into reg bucket dump. I also had good power with all moods. I just had to try it. I wish now that I did not try changing the regen spool hoses after moving to A & B ports. I kind of believe if I had done that it would not lift.

 

[oldnslo]

Leejohn,
When you had the hoses swapped and were raising in the regen mode did the FEL raise faster or was is similar speed to standard raise? Reason for asking is the regen systems usually have an over sized cylinder rod to provide the force and also have less rod end area resisting movement. Any pressure in the system is common to both ends of the cylinder so while trying to raise your loader in regen the cylinder is kind of fighting itself. Hopefully the attached circuits will explain what was happening better than I can. I.e. picture is worth a 1,000 words.

Please ask if this raises more questions

 

[Leejohn]

It did raise slower. I didn't about the rod size, well look at the link right now.

 

[bandit67]

How many lines are connected to the FEL valve. 6 or 7?

Very important to know if the FEL valve has power beyond circuit (7 hoses) or does Not have PB (6 hoses)

Please post a few photos of the FEL valve and of the overall tractor.

Does your tractor have power steering?

Post pictures of your hydraulic pump or pumps. Some models have tandem pumps, i.e. one pump attached to the back of the first pump.

Did the FEL come from the factory on a new tractor or was it added later?

As others have suggested, your description of how to raise the lift arms seems to be quite unusual. We need to figure out why that is.

Dave M7040

Not sure why I'm not getting notifications lately from TBN when replies are posted, but thanks to all for the feedback.

I have 7 lines coming out of the valve. PB goes back to backhoe, then backhoe comes back up front. Machine has dual pumps with hydraulic power steering.

Hose with yellow caps is the boom lift hose. Every other FEL and backhoe function is working fine - only issue is the boom control. Loader and backhoe have been on the machine since new, so for 6 years now. Issue with boom lift started a little over a year ago.





I got the new female QD installed late last week, so both QD's on the boom lift hose are new, and issue is still present.

At this point, I'm thinking there's something going on inside the valve with the spring or a check ball that is broken, hanging up, or something, so I'm thinking a valve rebuild is inevitable.

 

[bandit67]

FINALLY!!!!!!

I finally figured out the issue with my FEL boom not raising properly. I realized what was going on a week ago when I removed the FEL just to see how the machine handled mowing chores with the flail. I always figured the weight of the FEL would help balance the tractor a little better (it does) so the FEL has always been on for mowing duties. When I was finished mowing, I brought the machine down to the garage to blow all the dust off, and found hydraulic fluid had been dripping from one or more of the factory male QC poppets at the loader valve. The poppets were not seating properly, and were allowing hydraulic fluid to continue to flow through the QC's, regardless of FEL joystick position, thus creating a constant "bypass" situation at the valve.
I replaced all 4 complete factory QC assemblies today, and now I can't get the boom raise function to "fail", so I think the problem has finally been resolved for good.

Interesting part is that prior to these issues starting, the FEL had only been removed from the tractor once back when I first got it, just to do it. I would have figured repeated QC disconnects and reconnects would be harder on the poppets & springs than normal FEL operation, but I guess not. I just did the 200 hour service a couple weeks ago. This loader issue started about a year ago, closer to the 150 hour mark. I just never had time, or remembered, to look into it when the weather was good, since the majority of FEL use the last couple years has been for snow removal. Failed poppets so soon sure seems a bit odd compared to previous machines I've owned.

 

[Dave M7040]

Re: FINALLY!!!!!!

I finally figured out the issue with my FEL boom not raising properly. I realized what was going on a week ago when I removed the FEL just to see how the machine handled mowing chores with the flail. I always figured the weight of the FEL would help balance the tractor a little better (it does) so the FEL has always been on for mowing duties. When I was finished mowing, I brought the machine down to the garage to blow all the dust off, and found hydraulic fluid had been dripping from one or more of the factory male QC poppets at the loader valve. The poppets were not seating properly, and were allowing hydraulic fluid to continue to flow through the QC's, regardless of FEL joystick position, thus creating a constant "bypass" situation at the valve.
I replaced all 4 complete factory QC assemblies today, and now I can't get the boom raise function to "fail", so I think the problem has finally been resolved for good.

Interesting part is that prior to these issues starting, the FEL had only been removed from the tractor once back when I first got it, just to do it. I would have figured repeated QC disconnects and reconnects would be harder on the poppets & springs than normal FEL operation, but I guess not. I just did the 200 hour service a couple weeks ago. This loader issue started about a year ago, closer to the 150 hour mark. I just never had time, or remembered, to look into it when the weather was good, since the majority of FEL use the last couple years has been for snow removal. Failed poppets so soon sure seems a bit odd compared to previous machines I've owned.

Often the issue is of quick couplers not fully seating because of residual pressure in the loader circuits.

The couplers connect but not fully.

Often, turning off the tractor, moving all the control levers around to allow pressures to equalize and then re seating couplers solves most problems.

Dave M7040

 

[bandit67]

Re: FINALLY!!!!!!

That was not the issue with these QC's. Believe me, I tried numerous times over the course of months to release pressures and properly seat the poppets during my investigations, disconnecting, reconnecting, etc., but the problems of the poppets not seating properly continued with virtually no hydraulic pressure behind them. These poppets will not seat properly now when depressed, even when removed from the machine. This may be a rare condition, certainly nothing I had ever experienced with other machines, which I think is why it took me a while to track it down. Guess I got a bad batch of QC's. I believe it was actually only 2 of the 4, but to be safe, I replaced all 4.