3 Point Hitch Lift Control on Kioti LK35

[Tx Jim]

James aka k0ua
I'm a firm believer that information posted on the internet should be "accurate" not someones "opinion" especially on a tractor forum. I will not tell you to shut up. I'm getting a little long in the tooth but still not too old to learn. On most tractors I've been acquainted with the 3 pt control valve is the last valve to get hyd power. So please explain why the FEL control valve has 2 return ports(return & PBY) and how a needle restrictor valve will cause a relief valve to unseat? I think 2 return ports is to accommodate the excess flow of higher output hyd pumps. Older open center hyd systems only had one(1) return port(hose).
Thank you for your patience,Jim

 

[Tx Jim]

Are you talking about putting the needle valve interrupting the flow in the power beyond loop, or between the 3pt control valve & the 3pt cylinders? In the power beyond loop would mess things up & restrict hydraulic flow to everything. I'm not aware of any issues other than slowness for a restriction after a work port.

Let's discuss for the moment a tractor without a frt end end loader then if I'm thinking correctly there will be no PBY loop. Then if a needle valve was installed prior the 3 pt the excess would have to be separately routed to sump to avoid relief valve opening.

PS: I just took time to look at the valves J_J posted which would I think accomplish what I stated.

 

[k0ua]

James aka k0ua
I'm a firm believer that information posted on the internet should be "accurate" not someones "opinion" especially on a tractor forum. I will not tell you to shut up. I'm getting a little long in the tooth but still not too old to learn. On most tractors I've been acquainted with the 3 pt control valve is the last valve to get hyd power. So please explain why the FEL control valve has 2 return ports(return & PBY) and how a needle restrictor valve will cause a relief valve to unseat? I think 2 return ports is to accommodate the excess flow of higher output hyd pumps. Older open center hyd systems only had one(1) return port(hose).
Thank you for your patience,Jim

I did not say that the relief valve would open, with a needle valve in the Power Beyond circuit heading toward the 3pt valve. It could I suppose if the needle valve was screwed down , but it would cause heating of the fluid as it would act as a restriction in the fluid flow and would cause a constant pressure in the system. Ok There are 7 hoses/ports in a typical modern FEL control the 4 work ports, the IN port from the pump the PB port and a Tank/sump port. With the valve centered the fluid flow in the IN port, and out the PB port. NONE of the fluid ever, ever flows out the Tank/Sump port unless you move the FEL control spool valve to allow a path for the fluid from the work ports on the opposite side of the cylinder to get back to the sump. Do we agree on this point?

 

[Fallon]

In a power beyond loop most of the time full pump flow goes to the in port on a valve, then to the out port & on to the next valve. When you divert flow from the loop to a work port it pushes on 1 end of the cylinder (the other end of the cylinder gets dumped to tank). The valve partially or completely blocks the power beyond loop, pressure in all of the power beyond loop up until that valve rises until the cylinder (or motor or whatever) moves. When pressure rises because the pump is always pumping & the cylinder stops moving (to much load or limits out) a pressure relief valve will pop open (usually in the first valve in the loop).

If you restrict the power beyond loop (needle valve in it), it will put more load on the pump & everything else in the system all the time. If you only had 1 valve in your power beyond loop & no restrictions on your tank line, you should be able to tie them together with no issues.

If you put a needle valve between the 3pt control valve & the cylinder it would restrict flow when using the 3pt control, but not otherwise impede the power beyond loop. That's what I'm planning on doing for my Top 'n Tilt cylinders so they are slow & easy to adjust precisely.

You may want be carefull taking my advice however... Apparently I can't tell the difference between 1/2" & 3/8" JIC fittings, which has wrecked havoc with my TnT project for the moment. :banghead:

If you tie together the power beyond out port to the tank port, fluid would just go to tank rather than the next valve in the loop. Also depending on restrictions & what not, fluid could push against the tank port on a valve/cylinder & cause it to have back pressure working against the other side of the cylinder.

 

[Fallon]

Let's discuss for the moment a tractor without a frt end end loader then if I'm thinking correctly there will be no PBY loop. Then if a needle valve was installed prior the 3 pt the excess would have to be separately routed to sump to avoid relief valve opening.

PS: I just took time to look at the valves J_J posted which would I think accomplish what I stated.

From what I understand all modern utility tractors use a power beyond loop. First stop would usually be the loader valve, last the 3pt valve. If have no loader or other valves, it just goes straight to the 3pt. To add a loader or other valve, you cut the line from the pump & put that to the In port on the new valve. The out port (not tank port) from the valve gets connected to the other side of the line you just cut so the fluid can cary on to the next valve in the system.

Restricting the flow of the power beyond loop is a bad thing, it puts load on the pump & heats the oil. However temporary restricting or blocking that loop is how every valve in the loop does it's job, so temporary restrictions obviously aren't a problem.

 

[k0ua]

From what I understand all modern utility tractors use a power beyond loop. First stop would usually be the loader valve, last the 3pt valve. If have no loader or other valves, it just goes straight to the 3pt. To add a loader or other valve, you cut the line from the pump & put that to the In port on the new valve. The out port (not tank port) from the valve gets connected to the other side of the line you just cut so the fluid can cary on to the next valve in the system.

Restricting the flow of the power beyond loop is a bad thing, it puts load on the pump & heats the oil. However temporary restricting or blocking that loop is how every valve in the loop does it's job, so temporary restrictions obviously aren't a problem.

We seem to be on the same page, now if we can get Jim to say "uncle" we will be done!

 

[Tx Jim]

k0ua
Ok I'll say "UNCLE". The modern PBY loop came into being after I left a JD dealership in the late 80's Thanks for enlightening me. Happy Thanksgiving to ALL.
Jim

 

[k0ua]

k0ua
Ok I'll say "UNCLE". The modern PBY loop came into being after I left a JD dealership in the late 80's Thanks for enlightening me. Happy Thanksgiving to ALL.
Jim

Happy Thanksgiving Jim.

 

[SSdoxie]

Let's take this thread back to OP,s original question & complaint.
KiotiLK35; If you think too much flow is causing the problem, try lifting same attachment at various engine RPM. Faster engine runs = more flow, slower engine speed is less flow.
I see in a related thread from about a year ago, you posted question in how to increase 3pt lift speed. If you were getting too much flow to cause the jerk it would not result in slow lift, but have too fast of lift. Did you change the pump to a higher volume pump?

You state having to move the position control lever more than half way (6 on scale of 10) before any lift occurs then it jumps into position. That tells me you have some oil by-pass in the lift control requiring flow has to get to a higher rate filling the voids in the by-pass until enough pressure in built up to open load check to the cylinder. This extra by-passing oil could account for the slow lift speed.

Not knowing how close the LK resembles the CK or DK models, take the seat off and look at the lift control right next to where the drop speed linkage hooks up. Is there a Allen screw with a jam nut on it? If so the LK has an MLS valve like the CK & DK. This MLS valve is the adjustable flow orifice (needle valve as discussed in previous comments here). Inside the MLS valve are some fixed orifices that allow oil flow to pressure sensing spools that need to shift to control when and how fast the lift cylinder operates. If the that adjustment screw is turned in too far the lift will operate quickly but will continue to plush (jump up and down) when raised and trying to hold at given height. If screw is turned out too far, it will require more oil to flow before starting too raise, then vey likely jump into position when the spools shift.
Hopefully the LK has the MLS valve, it is easily adjusted. Put an attachment on the 3pt (heaviest 1 you have), raise the 3pt up a little over 1/2 full height, leave running about 1/2 throttle, loosen the jam nut and start turning the screw in (clockwise) until the lift arms start to pulse up & down, turn screw back out until pulse stops then continue to turn screw out another 1/2 to 3/4 turns.

Please post back on if you do have the MLS valve and results: More information we can get regarding similarities to the CK or DK models, more help those that have these models can help out.

 

[KiotiLK35]

Thanks SSDoxie. Will check out the valve you describe on my tractor today and see if it has similar adjustment capability. Will let you know.

 

[KiotiLK35]

Have reviewed my post from last year that SSDoxie refers to. I guess my description was confusing so just to clarify now…. I never wanted to increase 3PH lift speed, all I wanted to do was get rid of the jerkiness. I also confirm I have not installed a larger volume hydro pump - or made any other changes yet. If that means the 3PH lifts a little slower I don't mind as long as I can get a smoothe/gentle lift action. I checked out my tractor again and I do not see the adjuster beside the drop speed control that you describe. I did find a video on youTube that showed how to adjust the MLS valve on a CK20 so I understand what the adjuster looks like and how to adjust it - I just don't find one on my LK35. I also note that the CK20 is a completely different beast to my LK. Mine has the raised transmission tunnel and therefore does not have the flat work platform like the CK. LK also does not have any covers over the drop 3PH drop speed control mechanism, therefore no need to remove the seat or covers to examine the drop speed control. It's right there in the open just like my old Kubota L245.
I have retested the effect of activating 3PH lift/drop control at the same time as operating either the FEL or hydro remotes and confirm that you cannot operate the 3PH lift control at the same time as the FEL or the hydro remotes. The 3PH lift just goes on pause until you release either the FEL or the hydro remote function. Maybe this suggests the 3PH is at the end of the hydro circuit and therefore gets lowest priority? Further I can confirm that the smoothest 3PH response I can get is by moving the lift control lever swiftly from 0-10. That way I get a pretty smooth action, but I have gone through the full lift stroke, whereas I want to be able to just feather the 3PH up inch by inch (like when just lifting a pallet clear of the ground. The slower I move the lift lever the jerkier the lift action is and there is a small delay (maybe half a second) between me inching up the lift lever and the 3PH responding. I hope this further detail helps fill in the picture.
I have a PDF document of the hydraulic section from the Kioti workshop manual. It's about 25 pages. Can I post this as an attachment to this post somehow? I don't see an attachments link here, but maybe someone can help me out. I'm sure it can be done. I have also taken photos and video ofmy tractor going through the 3PH lift process. Again, is there some way I get them onto this post as attachments? Maybe if you guys can see my LK35 it will help.
Thanks again for your patience and support.
I have looked at J252's solution for his L-series of installing a pressure compensated flow control valve and the video of his final solution looks good in operation, although I could only find the "after" video, so I don't know what it looked like "before" his fix. Anyway, if I go down this path I understand it will allow be to control the flow to my 3PH from 0 to full flow. My question is, will this remove the jerkiness or just reduce the effect (but still be jerky)? Just want to be as informed as possible before I embark on any changes.

 

[k0ua]

Both pictures and PDF are easy to post. Multiple ways. Go advanced, manage attachments, pretty much self explanatory. So an LK is nothing like a CK or DK and sounds like a Kubota standard L with the transmission hump.

 

[Fallon]

I have retested the effect of activating 3PH lift/drop control at the same time as operating either the FEL or hydro remotes and confirm that you cannot operate the 3PH lift control at the same time as the FEL or the hydro remotes. The 3PH lift just goes on pause until you release either the FEL or the hydro remote function. Maybe this suggests the 3PH is at the end of the hydro circuit and therefore gets lowest priority?

In a power beyond loop (what all modern utility tractors use) the pump is continuously pumping. Hydraulic fluid flows from the pump into the first valve then out to the next valve & so on with the 3pt usually being the last valve in the circuit. When you partially or completely engage a valve, it partially or completely diverts fluid from the power beyond loop off to the cylinder (or motor, or whatever), resistance on that cylinder builds pressure. So when you engage a valve stuff downstream not working until you release the upstream valve is expected behavior.

I have a Kubota L3200 & am all too familiar with a jerky 3pt. I've seen a LOT of complaining & contemplating on the issue, but only a very few people who've tried engineering better solutions. And of the couple of people who've worked on it, several haven't had much success or said the engineering constraints are to hard. Some have had success with swapping in valves off the higher end Kubota Grand L's or what not though. To much work for something I'm not familiar enough with yet myself.

 

[J_J]

KiotiLK35

Tell me again why you can not operate both 3pt and FEL at the same time.

I explained how in a previous post, but here it is again.

If say your tractor can pump 10 GPM at max engine rpm, then 10 GPM is flowing through all valves to the tank when all valve levers are in neutral.

1. If you push the FEL lever to the max, and not in float, you will use all pump flow to move the cyl. 10 GPM.

2. If you push the FEL lever half way, you might be using about 5 of the 10 GPM available, and that leaves the other 5 GPM to flow to the 3pt. So by using both valves, you are using the 10 GPM pump flow.

Try this. Operate the 3pt and then fully shift the FEL valve. The 3pt should quit and the FEL operate fully. The FEL valve has priority.

Try again and see if you can not use both valves at the same time, using half lever on the FEL.

If you can't do it, tell me exactly what you did.

If you had a flow meter in the circuit, you could see the results.

 

[KiotiLK35]

OK J.J, will try again today just as you describe. I did read your previous post and repeat the test, so please don't think I just blew off you post. Seems to me that if I have FEL operating at all (even feathering rather than full tilt) then the 3PH will not lift at all - until I release the FEL joy stick. But maybe I am on drugs. Will repeat test this a.m. and post again. Cheers, Paul.

 

[J_J]

It is only logical that if the pump is pumping full flow, then, if you use a little of the flow with the FEL, then the rest is flowing on to the 3pt for use or not.

If you fully engage the FEL, you will have no fluid for the 3pt.

 

[KiotiLK35]

J.J. I understand your logic (always did) but I THOUGHT I was seeing different behaviour in my tractor. After running through the process again today I stand corrected, so I guess I was on drugs. Tractor behaved exactly as you described. If I am careful feathering the FEL and 3PH at the same time I can achieve a pretty smooth 3PH response. Of course this is not a practical ongoing solution, espec since you can't be watching your FEL and 3PH at the same time. I notice that if I activate the rear remote hydro lever I can achieve the same effect, which is lot easier since the remote lever and 3PH lever are side-by-side. I guess this would be a plausible temporary solution, but I am keen to make a more deliberate and graceful change - like the pressure compensated flow control valve. Thanks again for your patience and advice. Cheers, Paul

 

[KiotiLK35]

Hi Guys, was in the process of uploading the hydraulic section of my workshop manual when I discovered the 1 Mb limit on PDF files (hydro section is about 14 Mb) so I will cut down to essentials and post later.