Hmm, L3940 acting weird ALREADY

[beppington]

Disc'ed today, then used the FEL to level a very small ~10'x~20' area, & these two odd things happened while using the FEL:

1) At one point the HST pedal wouldn't go down to go forward, at all. Wouldn't budge. It worked fine in reverse, but wouldn't budge downward to go forward. Cruise control worked fine, was able to move forward that way just fine. While using the cruise control I again tried the HST pedal, but still no. I stopped & got off to see if maybe something had jammed the HST pedal underneath, but nothing, clean as a whistle actually. Jumped back on & wah-lah, it now works fine again. What gives?? Was this just a glitch & a normal part of tractor ownership?

2) 5 or 6 times the FEL's raising & lowering speed dropped to very very slow, barely moving either up or down. Several times when it happened, curling or un-curling the bucket then made it go up & down at normal speed again. What gives?? What could this have been.

Got about 13 hours on it, maybe it's just old & worn out now

 

[PHILIP8N]

I have had neither issue at 52 hours of ownership now. I assume you have checked your trans/hyd case level at the back of the tractor? Philip.

 

[dodge man]

I agree, check the fluid level. Also disconnect and reconnect the quick connects on your FEL. They may seem like they are on O.K., but sometimes one of them is not quite right. They could explain the FEL acting funny, but not the HST.

 

[Dead Horse]

I agree, check the fluid level. Also disconnect and reconnect the quick connects on your FEL. They may seem like they are on O.K., but sometimes one of them is not quite right. They could explain the FEL acting funny, but not the HST.

I have seen that exact thing on my neighbors tractor....... somethi ng was not qquite right on one of the hoses and it bound up the hyd pump so much the engine was down on power and the tractor would not respond very well.

I don't know how the fluid was getting around the valve block, maybe something to do with the power beyond circuit, but the hose was so jammed up we had to take a drift and ballpene hammer to release pressure in the line. Need to wear safety lenses when doing that job!

 

[beppington]

Thanks ... I'll disconnect them & re-connect tonight & see if it works.

Weird how the FEL worked fine for a while & then started acting up seemingly out of the blue. I guess they can just act weird when something's not attached just right.

I should've mentioned: The discing I did is on a 50' x 1/4-mile natural gas pipeline right-of-way that was rutted really badly when the pipeline people came in & cleared it maybe 2-3 years ago. I guess they come in once a decade after it's incredibly grown up, & then just rips the shreads out of it without any regard to what it actually looks like when they're done. They obviously did it this last time when it was very wet & left huge loader tire ruts all over the place; Of course now it's dry as can be & the rutted dirt is really hard. I'm trying to disc it smooth, but the ride is bouncy as crud as I go right now. Maybe the bouncing jostled one of the FEL connectors loose-ish, or cocked it to the side a little.

I probably should've just called the pipeline people & had them come smooth it out.

Now that I own it, I'll be keeping it bush hogged, at a minimum, so they shouldn't need to come in & do anything any more.

 

[beppington]

2) 5 or 6 times the FEL's raising & lowering speed dropped to very very slow, barely moving either up or down. Several times when it happened, curling or un-curling the bucket then made it go up & down at normal speed again. What gives?? What could this have been.

Still doing this occassionally I guess I'm gonna have the call the dealer tomorrow

 

[Dead Horse]

Oil level is good, right? if that is the case, sounds like the valve has a problem. Dealer can pressure test it.

 

[beppington]

I'll be trying to verify this tomorrow morning, but I may have discovered the slow lift/ lower FEL "issue" (with no rollback/ un-curl speed issues); I more thoroughly read the loader's manual while here at work today & found: "This control valve has two dump stage positions. The first dump position by moving the lever to the right features greater speed for dumping. The second dump position (to further right) is the "Regular" dump position. It has good power and control for dumping precisely. This position should be used when operating another implement with this control valve. These two positions are separated by a "Feel" position for your convenience."

Next page: "When taking off hydraulic power from port [D], the flow rate can be adjusted in two stages with the lever. The flow rate is high at position (R1) (which of course is the loader control's un-curl direction) and low at position (R2) (same direction, to the right, just further). Move the lever to position (R1) or (R2) depending on the attachment in use."

In my OP I said "curling" and/ or "un-curling" seemed to fix the slowness problem ... I bet I was unknowingly/ unintentionally putting it back into the higher speed mode when doing that.

Diagram from loader manual:

Yes I am a tractor noob ... Hopefully this will help somebody else.

 

[CHDinCT]

As I understand it, one position (I think the R1, but forget) is the re-generative position and it uses the oil flowing out of the curl cylinder to be routed back to the "in" side of the cylinder to some degree giving more precision for the dump function. The second position (R2) opens the circuit and lets the escaping fluid flow back to the tank resulting in a fast dump function. At least that's what I recall the difference between the two positions to be. I'm sure someone more expert in hydraulic circuits could explain it better. Glad you found your problem and it's not a defect in your new tractor.

 

[beppington]

No luck after all. My post above did not turn out to solve the problem.

That whole description only results in the dump speed of the bucket going fast when pushing the controller lightly to the right, & slower when you push it further.

 

[bitseeker]

Hi,

I think it is working properly, and that's what the manual says it should do.

"The first dump position by moving the lever to the right features greater speed for dumping. The second dump position (to further right) is the "Regular" dump position."

That configuration seems illogical, but it is probably what will work within the valve.

 

[beppington]

SOLVED finally. Turns out the 3PH's upper-end stop at the top needs adjustment.

When I pull my 3PH lever all the way back, the hydraulics continue trying to lift it even though it can't go any further. This is not only enough to slow the loader's up/ down action waaay down, it also affects the HST, i.e. the speed of the tractor! (It had not done this before, though)

I was making the 20-minute tractor drive to my property today & the tractor "seemed" to be bogging down, even though the speedometer read the normal 13-14 mph. I wasn't positive, but it just didn't feel right. I stopped & just tried to think, what could be wrong?? Anything? Nothing obvious, to me anyway. Tried different HST modes, tried some levers, but nothing worked. I decided it was all in my head & kept going. Then ... it started overheating. :shocked: What the heck?!?!?! OK, now the problem went from a little bothersome to serious as all get out. Pulled over & randomly tried all the levers this time. Remember before when curling and/ or un-curling the bucket would fix the slow loader? Not this time! Turns out, as soon as I dropped the 3PH just a hair, the engine pepped right up & all was good again.

The adjustment must've actually gotten more out of adjustment, as now I can lift the 3PH to the top & immediately hear the engine bog; It didn't do that before. That also causes the FEL to immediately operate slowly. It all makes sense now, but it was too subtle in the beginning ... I never heard any engine bog when it first started this little problem.

Something so simple ...

 

[irvingj]

Glad you got it figured out, good job!:thumbsup:

I've had similar situations with my GC when lifting the MMM (same as 3PH); I get a warning, however, when the stop is reached- a higher-pitched whiny noise, indicating hydraulics have reached the end of their travel.

Sort of like a parking-lot power steering situation when somebody cranks on the wheel and in spite of the noise continues to try to turn those front wheels just a bit more....

I've learned to listen for such indications!

 

[beppington]

I've had similar situations with my GC when lifting the MMM (same as 3PH); I get a warning, however, when the stop is reached- a higher-pitched whiny noise, indicating hydraulics have reached the end of their travel.

Sort of like a parking-lot power steering situation when somebody cranks on the wheel and in spite of the noise continues to try to turn those front wheels just a bit more....

Now that the engine clearly bogs, that's my indicator. In the beginning when the loader would change & go really slow, or the one time the tractor speed "seemed" a little slow, I couldn't hear any difference. Now I can bring the 3PH all the way up & very obviously/ noticeably bog the engine & hydraulics, whereas it didn't do that in the beginning of this saga.

 

[DiezNutz]

...I get a warning, however, when the stop is reached- a higher-pitched whiny noise, indicating hydraulics have reached the end of their travel.

Relief Valve.

Bep, you will want to figure out where the interference is and have it adjusted, since this is not normal.

 

[irvingj]

"Relief Valve." Yep, knew that, thanks. Guess my litlle GC's quiet enough that I can hear it....

 

[Dead Horse]

Hey guys........

I had this happen with my 3710 when I was running a snow blower on the PTO. (Years ago, and I had forgotten about it. A post above reminded me of it.)

The problem was that the PTO shaft was not cut short enough and at full "lift" it created a DANGEROUS hard stop for the lift geometry.

I say "dangerous" because the bearing in the tractor PTO output shaft is not designed for thrust forces.

Edit. never mind. different problem..........

 

[beppington]

My dealer told me the top of the left (when looking at the back of the tractor) lift arm has an adjustment to correct my problem. I haven't had a chance to check it yet.

 

[Chilly807]

Seems like a few Kubotas have had the same problem lately. The feedback rod tells the valve when the 3 ph is fully raised so as to stop applying pressure. The dealer should either send out a service rep or give you detailed directions as to how to adjust it properly. If they don't want to do that, we can walk you through the logical way to adjust it, particularly if someone here has a manual for the 3940.

Sean

 

[beppington]

My dealer offered to take care of it at the 50-hour service visit, but also gave me detailed instructions on how to do it myself, which I will go ahead & do.

Thank you ...