FEL hydraulic issue when raising boom

bandit67 · Mar 7, 2018

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.

Tx Jim · Mar 8, 2018

I wonder if relief valve in FEL spool valve isn't set correctly? You could install a gauge to check relief valve setting. Actually only other thing that one could check is clearance between spool & valve housing but if clearance is too much then a new complete valve is the only remedy. Does boom seem to have good lifting capacity? By "wired" do you mean cable controlled or electrical?

oldnslo · Mar 8, 2018

I would start by removing the cover on the end of the valve housing and look to see if something on the centering spring assembly has worked loose. Some of these valves have a bolt that holds this assembly together. If this works loose them the valve may not travel to the correct position.

Other possible problem is the load check is failing. Not sure how this would effect the operation since it should still raise with the spool shifted fully.

Leejohn · Mar 8, 2018

By what you said here (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.) it sounds like you have the boom and bucket hoses mixed up. The bucket only should have 2 moods on the dump side.

oldnslo · Mar 8, 2018

Lee,
If he has regenerative dump the loader would not raise in regenerative especially when loaded. Only two speed systems that I have seen use a double pump where you add the flow from the second pump for fast movement. Doubt Bota has that feature on his B3000.

bandit67 · Mar 11, 2018

Boom has good lift capacity even at higher throttle, as long as I don’t pull back too far. It is cable controlled from joystick at cab to valve attached to loader frame.

I assumed most loaders have this feature since both my B3030 and B3000 had/have the function that adjusts boom lift speed based on position of joystick- partway pulled back vs all the way pulled back. Hoses are not mixed up between boom & bucket. There is a powered dump along with float dump on bucket similar to the power down and float down on the boom. Also 4 corner positions to split functions such as boom up & bucket curl at same time, etc.

Pretty full featured loader joystick for the size machine.

This issue started last winter, after functioning flawlessly for the initial 4 years of ownership.

oldnslo · Mar 11, 2018

Bandit
Are there quick disconnects in the lines so that you can remove the FEL? If yes these can become partially connected due to something tugging on the hose. With the engine off and FEL on the ground move the joystick in all directions to relieve pressure and then disconnect and reconnect the lift lower disconnects.

Disconnects failing cause movement to slow or stop. Look closely at the hoses for lift lower when the FEL doesn稚 raise. Do both hoses stiffen & swell like they are under pressure?

Does neither hose stiffen or swell?

Both of these symptoms point towards failing quick disconnects.

Your 2 speed is what is called feathering the control. Partial movement of the joystick provides partial speed. Almost all FEL have this feature some are much easier to use than others.

bandit67 · Mar 11, 2018

I did buy a couple pairs of new QD’s, and replaced the lift line male QD at the loader valve, but have not been able to get the female QD off the hyd line. The male QD pin wasn’t seating dead center, and that initially seemed to help. I was planning on replacing the other QD, but am considering replacing some of the hyd lines completely, as a couple of the smaller lines at the bucket are starting to leak at the crimp fittings. Not all that impressed with the quality of the hoses on this machine compared to my B3030 with double the hours when I traded.

Dave M7040 · Mar 12, 2018

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