Bump up lift capacity of L3400/LA463 Loader

[McREBEL]

Thanks for all the input. I can see this is not going to be easy.

1)If I have only one relief valve (at the loader), theoretically it seems I could check the pressure anywhere (@ 3pt or loader) and the pressure would be the same since it all passes through the same relief valve (assuming nothing is plugged up). Again, I am learning here so there definitely could be something I don't understand.

2)If I have a separate downstream relief for the 3pt I can not find it on the illustrated parts diagrams on Kubota.com. Not saying it isn't there, I just can't locate it.

3)JJ, Why does it not work to check the pressure, without a tee, at one of the loader quick connect outputs? Wouldn't installing the gauge there with no tee be the same as maxing the loader lift or curl out to engage the relief? Not a smart elic question. I am trying to understand why doing it without the tee is not advisable.

 

[teg]

...Wouldn't installing the gauge there with no tee be the same as maxing the loader lift or curl out to engage the relief?

I plan to put this to the test... So J_J, should I put the gauge before or after the FEL?

 

[J_J]

If the FEL has a relief, you can plug the gauge into one of the loader QD, which come out of the FEL work port. In order to see the pump pressure you move the lever to cause flow to the line the gauge is plugged into.

When the lever goes back to neutral, no pressure will show on the gauge, and if you active the 3pt, you will not show any pressure.

In order to show pressure at any time the tractor is running, the gauge needs to be in the flow path.

If you install a hyd gauge in a tee in the tube going to the FEL in port, the gauge will show any pressure developed by any cyl.

I looked through the PDF for that tractor many times and could not find but one relief valve which is in the FEL valve. .

Keep in mind that some tractors do not come setup for a loader, and have a relief valve just for the 3pt.

The loader and valve is add on and does contain a FEL relief valve.

Some times there are three relief valves, the FEL relief, the remote relief valve, and the 3pt.

 

[rswyan]

... I looked through the PDF for that tractor many times and could not find but one relief valve which is in the FEL valve. ...

After looking at the diagram @ kubota.com for a B2920 that appears to be correct :thumbsup:

... Some times there are three relief valves, the FEL relief, the remote relief valve, and the 3pt.

That's how it is on mine: one for the loader, one for the 3PH (and/or rear aux hydraulic block), and one on my Prince SV stack valve, which are the rear remotes.

 

[Tx Jim]

I looked through the PDF for that tractor many times and could not find but one relief valve which is in the FEL valve. .
Some times there are three relief valves, the FEL relief, the remote relief valve, and the 3pt.

J_J
What is the adjustable valve(parts keys 130-270) for the 3 pt control valve for a L3400 if it not a relief valve for 3 pt? Parts key 150 outlined in red is a socket head screw.
Thanks,Jim

 

[stoyan79]

Finally had some time to measure my L3700SU. The gauge showed 2,200, so I crawled underneath the tractor and found out that the relief valve bolt is not screwed in all the way.

Whats amazing is, the tractor seemed very capable @ 2,200, and it would easily lift my 1,100lbs counter weight, hooked on a chain to the cutting edge on the bucket.

Got a wrench and started screwing it in, and the pressure kept increasing. It required quite a bit of force to screw in, so I am sure this won't become loose.

I screwed it, until I reached 2,650, and left it there. If I held the FEL lever a bit longer it kinda inched almost to 2,700.

I figured this is a good number as other make tractors of similar size are spec-ed @ 2,700 right out of the factory.

All measurements were taken @ idle (about 500rpm).

All in all it took just few minutes to adjust my pressure.
I purchased the gauge, the coupler and a reducer all on eBay for about $32.

Lets hope, I didn't just ruined my almost new tractor (2011 model with 39 hours).

 

[ritschner]

stoyan79, I have been running the same pressure you have now for almost five years and 400hrs on my L2800 with no issues.

 

[J_J]

J_J
What is the adjustable valve(parts keys 130-270) for the 3 pt control valve for a L3400 if it not a relief valve for 3 pt? Parts key 150 outlined in red is a socket head screw.
Thanks,Jim

Jim,

You guys keep trying to get me on something, and even if you do, I don't mind. He**, I make mistakes like everyone else.

McREBEL said he had a B2920, so I don't know what to tell you.

Look up the B2920 and tell me what you find.

I usually do my homework.

 

[J_J]

Finally had some time to measure my L3700SU. The gauge showed 2,200, so I crawled underneath the tractor and found out that the relief valve bolt is not screwed in all the way.

Whats amazing is, the tractor seemed very capable @ 2,200, and it would easily lift my 1,100lbs counter weight, hooked on a chain to the cutting edge on the bucket.

Got a wrench and started screwing it in, and the pressure kept increasing. It required quite a bit of force to screw in, so I am sure this won't become loose.

I screwed it, until I reached 2,650, and left it there. If I held the FEL lever a bit longer it kinda inched almost to 2,700.

I figured this is a good number as other make tractors of similar size are spec-ed @ 2,700 right out of the factory.

All measurements were taken @ idle (about 500rpm).

All in all it took just few minutes to adjust my pressure.
I purchased the gauge, the coupler and a reducer all on eBay for about $32.

Lets hope, I didn't just ruined my almost new tractor (2011 model with 39 hours).

Do you not realize that your relief valve is adjusted by shims and then you are supposed to torque down the cap nut to a certain torque and leave it there.

Somehow there is a misconception about how to adjust the relief pressure.

However, if you want to do it that way, then do so as it is your tractor.

Those shims come in different sizes and you can adjust the pressure using the right shims, with the cap nut torqued down correctly.

That kind of relief valve was not designed to adjust using the cap nut.

 

[J_J]

JJ,

I don't really know if that is accurate on that particular model.

FWIW, my tractor (B2910) has two PRV's (not counting the one on the rear remotes)

It's certainly true that the PRV on the loader likely sets the max pressure for the system (being first in the chain and furthest upstream) ... but it is also possible that if there is another PRV downstream of the loader valve - say for the 3PH - it might be set at a different pressure.

The data on your tractor is correct with a relief valve at the rear, and if you have remotes, you probably have another relief valve, and if you have a loader, then you probably have another relief valve.

Go ahead and look at the PDF for the B2920 and tell me what you find.

Your tractor probably came from the factory with only the 3pt relief, and has the tractor set relief pressure.

The loader and rear remotes are add on.

The other relief valves should be set the same, unless you want to set them different for some reason.