My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

[Harvest Moon]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

any ideas what valve is in a l3400 DT-f 75xxx

So, far I don't know the serial # break for the latest valve to be published. If the hitch works in limited broken movements but doesn't jerk the machine to much and was purchased or built before 2008 it's probably P/N: 31351-39604.

If it seems worse than above and you bought in 2008 or later then maybe P/N: YR908-00102. We know very little about this valve other than it's generated some complaints and it replaced 31351-39604. Messicks noted it to be an anti-fall valve?

Messick's posted the serial number breaks on 1-16-2006 for the original upgrade to valve 31351-39604, maybe he can help us find out when Kubota switched to YR908-00102?

Boy, if Neil answered everyones requests he wouldn't have time to run his business. I appreciate every one of his comments, even when I disagree. Now if he could just slip us the password to that "online service center" Kubota keeps.

 

[ht1]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

My hitch seems to operate closer to the bad part # but not quiet as bad,
my tractor was bought new in May of 08'. One thing I noticed from some
of the diagrams is that my position control rod that links the 3 point hitch
to the position control valve is straight, and the rod in the diagrams has a bend in it. Also my position control rod rubs on the top of my differencial.

 

[MessickFarmEqu]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

Messick's posted the serial number breaks on 1-16-2006 for the original upgrade to valve 31351-39604, maybe he can help us find out when Kubota switched to YR908-00102?

It was a very recent change. From what our documentation says it was a switch to an anti-fall valve. It was nothing related to what you guys have been talking about.

 

[ccsial]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

It was a very recent change. From what our documentation says it was a switch to an anti-fall valve. It was nothing related to what you guys have been talking about.

Could it be one of those "fixed one thing, broke another" ?

 

[Harvest Moon]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

It was a very recent change. From what our documentation says it was a switch to an anti-fall valve.

Seems so self explanatory but can anyone describe exactly what an anti-fall valve is? And maybe why they might switch to one, at this point?

 

[EE_Bota]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

If most of you are now satisfied with your lift, and now consider this an intellectual pursuit, knock yourself out, and enjoy! I am covered up with too many such pursuits, and I was mainly interested in having people like their lift performance, not so much the hydraulics....too much like work. The link below may get you started.

If you read at least 5 pages of this link, you will begin to see what you are up against, and why guessing what goes on in certain valves that look similar, but perform differently, is not likely to be that much fun. (Heck...depends what you consider fun I guess.)

(remember..yours are open center proportional, since a solenoid valve would be discreet (bang-bang)...a bit of a trick.)
Oil Hydraulic Systems: Principles ... - Google Book Search

I hope the link does not go stale quickly..it is a book preview. It discusses land overlap of spool valves, reaction forces, over reaction, etc in probably as much fun detail as many of you would like! It's fairly easy reading if you are used to reading such things.

As for the question of what is a anti-fall valve. It is to keep the lift from falling. But..beyond that...it could be accomplished in a number of ways, and for a number of reasons, all of which apply. If the lift control lever was in the up position and the lift were moving up..at the same time a power beyond hose bursts, the lift can fall. If the spool were cut to accommodate smoother lifting, some cuttings would require a check because for brief periods, the cylinder, tank, and pressure port can all be connected together. You would not like asking the lift to go up, only to have it drop a bit first, then go up.

As for what is the device itself....if can be a check valve (least likely), a pilot operated check valve (perfectly acceptable), or if the lift quarter-inches up AND down, it is most likely a rate based device that does nothing unless the oil exits the cylinder faster than a pre-set speed, and that will cause the valve which has NEVER moved before to suddenly shift and lock down the hydraulics so that the lift will never go down again until such time as it is raised first. Scissor type material lifts often have this, and sometimes call it a hose burst safety valve. Good luck!

 

[ccsial]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

It's interesting that Jap hydraulic engineers in 1982 could make a silky smooth 3PH on a fairly simple CUT, witness my Ford 1910 by Shibura, and today Kubota can no longer do that.

 

[canoetrpr]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

ccsial:

Having never owned a tractor before, how silky smooth is your old Ford's?

Does it have an infinite range of increments and how sensitive is it to the position control?

I'd be really interested to compare to the 1/4 inching variety that we have with something that is really smooth - both with weight on it.

 

[GMtb42]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

Update ;
I got the spring and washer today , and put it in the LCV , it does make a small amount of difference in the lift speed , slower , and responsiveness to movement , slower .
There has to be something inside the smooth PCVs that we can't see that is different , different sized ports , more , less .
Another piece to add to the puzzle .

 

[Harvest Moon]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

Thanks EE_Bota, again for all the help! Great link too, I hope to spend some time reading up.

Wow GMtb42! Glad you gave it a shot! It's great to have your piece of the puzzle.

Would you say that it is better with the spring or just different? If it's better, was it worth the approx. $10?

I know the smooth PCV has an extra spring.