Kubota l4610 slow fel poerformance

[emanaresi]

I posted a few months back with some concern regarding my FEL on my kubota L4610. I never had time to do much work on it then, and now would really like to get it up to 100%

There are a couple issues that may or may not be related, and I need some advice here. The front end loader raises and rolls back much more slowly than it should. I believe this indicates some kind of restriction or maybe a poor performing hydraulic pump (I hope not). I have been told in the past that I should get a pressure gauge and plumb it in to help diagnose the problem. I would be happy to do that if you can tell me what gauge I need and where it should be plumbed in. The FEL has plenty of strength, I have been able to lift overflowing buckets of heavy fill dirt with it, but it is definately slower than it should be.

Another issue is related to the fel control valve. it has a single joystick that comes through a square shaped guard. When you pul the lever back to lift the fel, it contacts the guard and is therefore limited in its travel. I have removed the guard thinking that it may not be travelling to the full lift position, but if you pull it further than where it is stopped by the guard, it stops going up. Is the guard supposed to be the stop, or should the spools in the valve have some sort of stop so they can't be moved beyond the intended range?

Thanks for any advice or assistance. I look forward to figuring out what the issues are and fixing them.

 

[J_J]

Hydraulics:
Type: open center
Pump flow: 9.6 gpm [36.3 lpm]
Total flow: 14.4 gpm [54.5 lpm]
Steering flow: 4.8 gpm [18.2 lpm]

Have you checked hyd filters and and screens in the hyd system?

Is the fluid warm to hot when trying to raise the loader. Is it not cold in NJ now.

You have 9.6 GPM hyd flow, so remove both hoses from the loader cyl and place a bucket and do a flow test.



One gal in 6 sec = about 10 GPM.

So if your engine is running at max rpm, you should be pumping 9.8 GPM. That means that every 6 sec, you are pumping a gal of fluid, so do not drain your reservoir.

Keep your reservoir filled

When you move the levers, do you have equal spool travel in both directions. You should have more spool movement if you go into float.

Have you re-set all the loader QD's?

Have you installed any fittings that might have restrictors in them?

Do you have any air bubbles in the tank?

If you want a permanent hyd gage, then mount it in a tee in the loader valve IN port and put it where you can see it. Then you can use it to monitor and trouble shooting the hyd system.

You can also build the hyd test gage set so you can plug it into any QD to test that function.

Here are a few pictures of hyd test sets.



.

 

[emanaresi]

The weather is cold now, but performance has been the same since I got it in the spring. WE changed the hydraulic fluid and filters after we bought the tractor.

We do have a bradco 511 backhoe attached to the power beyond port on the loader. I don't think that should effect the loader performance though...

When you say to remove both hoses from the loader cylinder, where exactly do you mean? I don't want to mess that up... How long can I run it before the reservoir would be dangerously low?

I will recheck the QDs, that could be it... Where do I get a gauge like that and how do I know what fittings I need, I don' think theyll be hardware store fittings... I do have a spare QD fitting.

What does the hyd pressure tell me, whether or not to adjust the bypass valve? Anything else?

 

[J_J]

The pressure gage is only going to tell you the pressure the cylinders are operating.

This is a liquid filled 3000 hyd gage. You might find one at TSC.

3000 PSI 2.5" LF LM GAUGE

Just find hyd adapters to put it together. Hyd vender, shop.

Remove the two work port hoses at the cyl and place those end in a bucket. Pull lever back fully for 6 sec.

If you can get one gal in sec, then you can assume the pump is at least pumping.

Mark your 5 gal bucket in one gal increments.

You will need to know the tractors relief setting. If the cyl can max out at that pressure the you can assume the pump and the vlave and the cylllll are working good.

GPM's determine the speed of operation, with you as the controlling agent.

If you plug the gage into a QD, and retract the cyl and hold it till the relief comes on, that is the cyl potential pressure.

Bore size and pressure determines the hydforce in lbs.

 

[oldnslo]

If it lifts full buckets of dirt it is probably not a pressure issue. In hydraulics flow equals speed of movement while pressure equals force of movement.

A simple way You can calculate approximate flow in GPM If you know the cylinder sizes on your FEL is to time them over a given stroke. Both MT bucket and loaded bucket. Is there a significant difference in time for the same stroke?

formula for figuring flow Vs cylinder speed is Flow rate (GPM) = {cylinder area (Sq inches) times velocity inches/sec} divided by 3.85

The fact that you say removing the cover allows the valve to travel to point where cylinder movement stops would indicate a potential problem at the control valve spool. Most valves have stops built in to limit max travel.

 

[emanaresi]

Is it more likely that I have a restriction somewhere? or that I have a pump issue? How can that be determined?

 

[Leejohn]

Roy kind of sound like the spring detent or float part of the spool has come unscrewed doesn't it?

 

[J_J]

Is the operation of the 3pt satisfactory.

Is the sump screen clean?

It is kind of doubtful that both spools are doing the same thing, [slow] unless the flow is being impeded. Are all the return hoses good and not kinked?

After doing the other test for flow, then remove the cans on the bottom of the spools and inspect , clean and tighten up everything and lube well.

You might also verify that the 3pt is in neutral.

 

[emanaresi]

Where would I find the sump screen? To be honest I haven't really used the 3pt hitch, the backhoe has been on almost exclusively since I bought it.

 

[Leejohn]

This well help you with the loader valve. The screen is on the right side of the trans case. Save that for last until you have checked everything else, because you have to drain all the oil out.

I had put before the screen was on the left but it's on the right. Just in case you read the post before I changed it.