L39 loader problem

JimMorrissey · Sep 26, 2005

Slowly but surely the loader on my L39 has decreased in strength over the last six months. The first day I owned it, I could easily lift the entire front end off the ground to max lift (no problem). The other day I tried to lift the front end so I could get a hose underneath to blast out a bunch of muck and it couldn't lift the front end! It couldn't even lift it six inches. It got a few inches and that's where it stopped dead. It must be something that can be adjusted. I just hope it's not something major like main cylinder(s) leaks.

I have the dealer coming out to test some things. I'll keep this thread posted with the results. Anybody else encounter anything like this (L39 or not)?

I've posted the attached picture before, but it gives you an idea of what it could do not too long ago. I only wish for that performance now. Got it buried up the axles the other day again and realized I couldn't lift the front end. /forums/images/graemlins/mad.gif

KennyV · Sep 26, 2005

Jim, if your cylinder(s) are leaking they will get hot, you should be able to feel a big difference in the temp of the leaking cylinder. KennyV

SkyPup · Sep 27, 2005

Jim, good luck on the fix. I haven't had that problem at all, in fact the ANBO Grapple I've been using lately itself weighs 850 pounds, double that of the OEM bucket, and I have no problem lifitng the front end off the ground. In fact, this past weekend I was digging out some stumps and had to lift out the root ball from the hole with the FEL and it was able to lift up the entire back of the L39 with the BH attached as high as I risked going....

mike69440 · Sep 27, 2005

My loader is still weak

With the stabilizers down The loader will not pick up the machine. Nor can the loader come close to picking up the back of the machine, even one wheel with an offset load.

Pressure from the main pump is 2650 psig when the dealer serviceman did a field visit., so no matter how dealer set the loader valve is set, that all the pressure I make.

I want to know where on the main pump is the relief valve is and where to measure the pressure on the valve. What size AN fitting do I need? I can get calibrated gauges from work.

Any help is appreciated.
Thanks

Mike Witzgall

JimMorrissey · Sep 27, 2005

Mike,

I think I'm right there with you....not happy about it.

They are coming to do some field testing soon and will give you some numbers and testing locations when complete.

Feel free to print off the picture of my machine and show your dealer what the loader is supposed to do.

JimMorrissey · Sep 27, 2005

Good call. I'll check it out. Thanks.

JimMorrissey · Sep 28, 2005

Mike and Sky,

Can you do me a favor...I need to know how each of your machines react to these two simple tests:

1. With brake on, curl your bucket with the cutting edge straight down and attempt to lift the front wheels of the machine. Result? How far in inches lifted...

2. Engauge the rear stabilizers fully and then attempt to lift the front wheels of the machine with the bucket curled. Result?

I need this input for the dealer when he shows up.

Thanks /forums/images/graemlins/smile.gif

SkyPup · Sep 28, 2005

Jim, I'll check it out this weekend, I need to dig out a new fire pit so will have it running.

JimMorrissey · Sep 28, 2005

Doesn't have to be exact. Just need a rough estimate.

JimMorrissey · Sep 28, 2005

I have noticed that the hydro fluid is down again, about two quarts and some of the hydro connections on the loader are covered in a thin film of oily dirt, but some are not /forums/images/graemlins/confused.gif This leads me to believe that some of the dirty connections are leaking a bit. I wonder if that's enough to cause this problem?

I'll have to ask them to go over all the connections as they should have when it was delivered from the factory.

KennyV · Sep 28, 2005

Jim...
The dirty connections are probably leaking, but for this to be your down pressure problem, you would be spraying fluid all over the place.
I think your first assumption was probably accurate. Hydraulic fluid is bypassing, (leaking) somewhere in the system. This can happen in the cylinder(s), control valve, or the pump bypass. Since you have not noticed a reduction of the back hoe performance, I would not first suspect the system pump pressure relief.

You should be able to lift your tractor with the bucket dump cycle. While doing that the boom cylinders should not expand. If they do disconnect them at the quick disconnects and try it again.

You can check the control valve by switching the quick disconnects for loader curl and boom… that will isolate the individual valves.

If you have rear remotes, run the output from a rear remote set to your loader cylinders that also should check the cylinders. Rear remote should have the same PSI as loader valve at full.

This is getting long but unless your complete hydraulic system is low on pressure one of the above checks should isolate a problem. KennyV.

mike69440 · Sep 29, 2005

</font><font color="blue" class="small">( Mike and Sky,

Can you do me a favor...I need to know how each of your machines react to these two simple tests:

1. With brake on, curl your bucket with the cutting edge straight down and attempt to lift the front wheels of the machine. Result? How far in inches lifted...

MCW Ans.
My loader is a weakling. Dealer cranked up the relief valve, which helped a bit. Main pump Pressure is not right. Only 2650 PSIG.
Loader Arms will Lift the machine all the way just barely.

If I try to lift machine using the bucket curl

2. Engauge the rear stabilizers fully and then attempt to lift the front wheels of the machine with the bucket curled. Result?

MCW Ans.

I should lift, but never could. Skypup's can I think. Mine never could. Dealer replaced defective loader valve and said plunger was mushroomed over on original loader valve from Factory? New Loader valve made no difference.
I need this input for the dealer when he shows up.

Thanks /forums/images/graemlins/smile.gif )</font>

Main Pump Pressure only 2650 Psig

We need to find out how to get in touch direct with Kubota Engineering!

JimMorrissey · Sep 29, 2005

What should the main pump pressure be? I thought 2650 psi was correct......

Sky says he can lift the front end with the stabilizers down. Mine can't...not even two inches. No problem with the brake on....lifts it right up without hesitation.

SkyPup · Sep 29, 2005

The main pump is factory preset for 2,650psi.

JimMorrissey · Sep 29, 2005

OK, with the help of SWinTexas05 (Simon) I'm thinking I might be OK. He pointed out something that I should have realized. Basically there is no way for the L39 to lift itself with the stabilizers down. The machine weighs close to 9,000 lbs and the loader would be tasked with an impossible feat being that the stabilizers don't roll easily and primarily that the fulcrum is much further back adding a tremendous amount of weight. Simon mention that he has the same problem with much larger equipment.

My machine currently lifts the front end with the rear wheels on the ground...effortlessly. So how did I get it up in the air so high with the stabilizers down (in the picture)? I remember now....I lifted the front with the rear tires on the ground as high as it would go, then I used the BH to lift the rear end and drop the stabilizers, then I'd lift the rear a bit more until the stabilizers were fully extended. Maybe I'm not having problems after all and I'm just trying to lift 3,000 lb boulders? Could it be that I'm asking too much of a small TLB?.....Never /forums/images/graemlins/tongue.gif

I'm still going to have the dealer check the hydro connections and check the pressure. I have a feeling all is well and I cried wolf with the dealer. Not good. Oh well.

Thanks for the PM Simon! Appreciate clear thinking.

BTW: Does anybody know if a loaders down force is equal to the lift force?

KennyV · Sep 29, 2005

Jim
The lift force is greater than the down… more piston surface on the lift side. On the down side there is a rod taking up some of the piston face.
I thought your first picture was what your tractor was originally able to do… glad it is not a degrading problem with your hydraulics… all is well. KennyV.

JimMorrissey · Sep 29, 2005

It was....but I forgot how I got it in that position /forums/images/graemlins/tongue.gif Then I figured out that I must have done it by lifting the front end and easing up the rear end with the hoe. I think I just convinced myself that something was wrong. Stupid.

So if the lift force is greater than the down force, then that totally makes sense that it can't lift basically the whole machine with the stabilizers down.