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

[PILOON]

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

Reading this trend kinda reminds me of a water pump system problem which gets me into your discussion.

If you decrease the flow, you will increase the pressure as pump is fixed gear type and it would want to surge.

I suspect a pressure relief valve would do the trick, HOWEVER the excess pressure and volume needs to be diverted (bled) back to return to tank line or surging WILL occur!

The relief valves that I have seen are kinda like a block of metal with in/out plus a 3rd to bleed away the excess fluid.
They have a screw adjustement to tighten/loosen (raise/lower) the setting.

Should be easy enough to plumb a couple of 'T's to accomodate such a valve.

I suspect that the factories have been installing bigger and bigger pumps to meet demands but have not re-designed the 3point system to accomodate the higher flows.

A farmer tends to drop his 3point implement and work all day at that setting.

We want fast loaders and precise 3-point to maintain our pristine driveway which a farmer cares little about as long as he does not get stuck.

Hope this helps!

Good luck.

 

[canoetrpr]

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

Here's a photograph of my hydraulic block. The port furthest to the left (towards the rear of the tractor) is where the pressurized fluid from the loader (or rear remote in my case) PB port goes in to feed the 3 PT valve.

The 3PT valve is the last valve in the circuit.

In my picture, you see a hose that hooks up to this to go towards the rear of the tractor. This is because I have rear remotes. If you don't then the hose from here goes to the loader instead. In my case the loader is the first valve in the circuit, then my rear remotes then the 3PT valve.

The port that is furthest down on the right hand side is the return to tank from the loader. Depressurized fluid that has been used up by the loader valve is returned to the tank here.

So the theory is:

- What we need is a flow control valve in between the loader (or rear remotes in my case) PB port and the PB inlet on the hyd. block that I have pointed out.

- The tank port that I pointed to (furthest down on the rhs) can be teed to so that it used fluid from the loader and excess fluid from the flow control valve can be returned to the tank. This is is the only line that can be teed.

Easiest way I think to do this:

- There is a nice area just under the loader valve where a flow control valve can be attached. The loader valve is bolted on to a plate that is welded onto the loader frame. The plate that the loader valve is bolted onto serves as a good spot IMHO for those that don't have rear remotes, to mount the flow control valve on.

- Simply follow the hose from the PB port of the hydraulic block (furthest to the left), to where it connects to the loader valve. This is the PB port of the loader valve.

- Disconnect this hose from the loader valve and connect it to the OUT of the flow control valve.

- Then connect a new (small - 1 to 2 ft should be plenty) hose from the PB port of the loader - where you unhooked the original hose, to the IN port of the flow control valve.

- Then connect a new hose from the EXCESS OUT port of the flow control valve and route it to the hydraulic block.

- Tee the TANK port of the hydraulic block, reconnect the hose that was already there (from the loader) back to it, and then connect the hose from the EXCESS OUT port from the flow control valve to the other opening of the tee.

- Open the flow control valve all the way, fire up the tractor, and adjust the flow control valve until the 3PT jerkyness goes away.

I would estimate that the total for parts - flow control valve, shipping, one extra hydraulic hose, fittings would probably be ~$125. Maybe a couple bucks for hardware to mount the valve to the loader's bracket and a can of Kubota orange paint to paint the flow control valve - say another $10 to 15 bucks, so that it looks like it belongs there . Total probably $150.

Not sure when I will try this out as I'm not suffering nearly as much as you guys with the new jerky 3 PT valve. I'd like mine to be smoother just so I can feel warm and fuzzy on the inside. This setup REALLY needs to be tried by someone with one of the newer jerky 3 PT valves. I predict that the difference to my setup since I have the improved 1/4 inch at a time valve will be more suttle.

Bear in mind that I have written the above note with a user who does not have a rear remote setup primarily in mind. The EXACT same thing could be done if you have rear remotes and your rear remotes will also get the reduced flow - in addition to the 3PT valve. Now this is not an issue for someone line me who uses rear remotes for a top n tilt + snow blower chute. However if you have a log splitter or something that is hyd driven and needs the additional flow, it might be best to modify the above so that the flow control valve is installed between the PB port of the rear remotes and the hyd. block, instead of the PB port of the loader and the hyd block.

 

[canoetrpr]

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

But, is it still just a guess that changing the flow rate to the PCV will solve the problem?? And if it is a fixed rate pump, does it mean anything that the PCV seems to function the same at different RPMs like teg pointed out?

I'm guessing the proof is in ht1's post, has anyone else tried this:

I prefer to call it a "theory" rather than a guess I have some confidence that this will work given that restricting the flow by installing 1/4" hoses on my TnT setup works to give me feathering control on them. But you are quite right - this is still a theory and I am certainly not 100% confident. This really does need to be tried by someone with one of the really jerky setups to see the before / after performance.

I never did try the loader with the 3pt. Meant to do it today but ended up trying to finish up a box blade modification project I have had going for EVER. Finally got the primer on my modifications and will paint tomorrow.

 

[jfay]

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

OK, so I took a little video today of lifting my L3300 3 point hitch and posted it on youtube with the title "L3300 three point lift".

YouTube - L3300 three point lift

As I posted before, this older tractor seems to lift pretty well. It moves up pretty smooth at full speed. When trying to move it up slowly, it gets a little jerky, but nowhere near as bad as some of the newer tractors discussed here.
Hope this helps.

 

[Harvest Moon]

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

Thanks jfay, It's great to have the visual comparison. I think most of us L3400 owners would be pretty happy if our hitches worked as smoothly as yours.

I looked up the L3300 on tractordata.com and saw that it has a hitch capacity of 3090 lbs. Do you have a manual that you can reference to confirm the lift capacity and the relief pressure if it's in there.? I'm trying to get a sense of how much larger your hydraulic cylinder might be.

 

[Harvest Moon]

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

Here's an observation. Wondering if it means anything to the discussion.

When the position control lever is raised... say from 2 to 6, it activates the PCV, either by adding or removing pressure, not sure which. As the hitch actually rises it moves the feed back lever into a corresponding position to ultimately de-activate the valve when the hitch reaches the hight corresponding to 6. If I'm understand it correctly.

So, there really is no feathering involved like with the loader joy stick. With position control the valve is closed, the valve is open and then closed again.

The earlier PCV seem to automatically go no flow to full flow very rapidly when the adjustment is made and from full to stop just as fast.

But the PCV from the L3010 seems to respond the the same on and off with a touch of grace. The difference in springs in the L3010 PCV may ease the action of the internal components in this valve, not by restricting flow or tempering fluid but simply by adding a gentle smoothing resistance within the mechanism. It tempers the on/off to oooonnn/oooofff, the "switch" tempers the fluid. Maybe.

The LSV is a check valve and works like a "switch" too. Maybe the spring works much the same way in the LSV and offers some smoothing action. I'm not giving up on the extra spring until I figure out why it's there.

If it weren't for ht1's experience with the loader smoothing out the hitch I'd really be wondering if slowing the fluid would just result in slower jerks. At least with the earlier valve.

 

[canoetrpr]

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

Harvest. That is a good observation.

All of our theories are just theories at this point. None are really proven.

I hope that you do see the desired effect with the spring. Looking forward to seeing how it goes.

One thing that I do find with the PCV on my L3400 is that even though there seem to be an infinite granularity or ranges on the lever - you have to move the lever quite a bit - pretty much all the way from say 5-6 for the hitch to move at all.... vs. small gradual movements that you would expect would occur when you moved from say 5.25 to 5.5. I think that the observation that you are making relates to this. For some reason, these valves tend to open all the way or not at all on our tractors.

 

[teg]

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

Any chance that the valve waits till it hits a certain PSI then burps out enough fluid to move 1/4"... which would reduce the psi until the handle moves again. Move handle, increase psi, burp... it would not matter if flow is moving fast or slow. Just a thought (or more like a monkey wrench).

Which would suggest the valve is the problem or if a stronger spring might reduce the burp to say 1/8" or less. and yes I have absolutely no clue what I'm talking about. If someone can explain how the valves work... we might get another piece of the puzzle.

 

[Harvest Moon]

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

Got the valve and about an hour. I'm going to see what I can do with the two.

 

[mjfox6]

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

Get offline and get that thing installed!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!