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Discussion Starter #1
Hey all,

I have gone through every thread and I can’t find anything about hydraulic shimming that explains or shows what is being done. A lot of posts saying the did it, or the did this size whatevers, or how much psi. I have no idea where a shim goes, how many are required, anything.

I have a new toy coming and I am planning on getting a fel for it. I am really curious where this shim goes on a x739. Is there one per hydraulic line?

While I’m at it.... lock outs? Why, where, when are they used. Again a lot of posts says installed lockout all good now. Sorry nit helpful to newbies to hydraulics.

Any simple information you can share or point me at?

Thanks
 

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Never did the shimming thing, but the lock out valve is used for blades. It prevents your mower lift brackets from going up and down. It gets installed right behind your front ports. It replaces one of the 90 degree fittings, its a simple knob type.
 

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Shimming

I "shimmed" the hydraulics on my 790. In my case, and I think this is a common use of the term it's a way to adjust the relief valve to increase the pressure in the system before the relief valve opens.

I forget if I installed 2 or 3 shims to bring the system up to rated pressure, checked by a gauge. (Kenny's Bolt on Hooks sells a gauge set up.) It is not recommended to take the system higher than rated pressure, thus a gauge is really necessary.

I would ask the dealer to check the pressures in your system before delivery. They should be within specification and you really shouldn't have to deal with it for some years until the system wears some. I bought my tractor used so it was up to me to check.

Treefarmer
 

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Discussion Starter #4
Very helpful guys, much appreciated.

Shimming - doesn’t each tractor model start at roughly the same pressure? I’m assuming the pressure is based off the opening size. It seems logical that there would be a certain size crates certain pressure so you could just buy one that is designed for 1100 or whatever. Or is there some sort of dilating orffice that allows some regulation despite the shim size?

Cut off - now I understand what it does (isolation of an unused supply essentially). Why would this nit be included if you bought a machine with a blower or plow? Does this mean my new machine will be trying to actuate my blower lift and another unused line? I’m still a little lost here.

Thanks in advance if you can shed additional light.

Chris
 

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I am far from a expert when it comes to hydraulics. Hydraulics are like electricity it will go the the path of least resistance.

Really the best thing you can do is some Google searches on hydraulic principles if you want to understand it. Hydraulic fundamentals are all the same.

As stated really a guage should be used when charging the relief valve pressure. You do not want to have to replace a pump or cause a safety issue.
 

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Pressure

Very helpful guys, much appreciated.

Shimming - doesn’t each tractor model start at roughly the same pressure? I’m assuming the pressure is based off the opening size. It seems logical that there would be a certain size crates certain pressure so you could just buy one that is designed for 1100 or whatever. Or is there some sort of dilating orffice that allows some regulation despite the shim size?

Cut off - now I understand what it does (isolation of an unused supply essentially). Why would this nit be included if you bought a machine with a blower or plow? Does this mean my new machine will be trying to actuate my blower lift and another unused line? I’m still a little lost here.

Thanks in advance if you can shed additional light.

Chris
While most tractor hydraulics are in a similar range, they are not always the same. And a 2-300 psi difference is 10% or more and can make a difference. The pressure is determined by the pump, flow demand and relief valve. The pump generates pressure and flow through the system. The demand flow can and will drop pressures if it's more than the pump output. The relief valve allows the pump output to bleed back into the reservoir (usually the transmission) and limits the pressure to system design limits. This is especially important for limiting damage from sudden loads like having a FEL bucket full and going across a rough field. That bucket bouncing up and down generates a lot of additional pressure on the system. If you are using the FEL control at the same time it bounces, that pressure can build in the system all the way back to the relief valve. (If you aren't using the FEL control, the additional pressure should be contained within the FEL system but can still blow seals on the loader and control valve.)

The same thing can happen with a load on the 3 ph bouncing up and down. If you have a new tractor under warranty, you do NOT want to increase pressure over specifications as that is likely to be an issue if you have any hydraulic related problems. Let the dealer check the pressure before delivery and adjust if necessary. Odds are very good that it will be within specification and will stay that way for a long time. Enjoy using your tractor and save your maintenance time for things like fluid checks, tire pressure checks, greasing etc. Hydraulics are one system that you should not "mess around with" just to see what happens. If you inadvertently do something to cause a problem, it will get very expensive very quickly and if your efforts caused the problem, your dealer will likely realize that the system has been tampered with and refuse a warranty claim.

If you want to learn about hydraulics, that's great and there was a good link posted by someone. That doesn't mean it's a good idea to modify systems outside of the design parameters because they are systems, with valves, seals, pumps etc. all designed to work together. If you change one thing, it affects everything else to some degree and results are not always positive. Use the proper oil, keep the system clean and you can mostly ignore what's happening inside.

Treefarmer
 

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Very helpful guys, much appreciated.

Shimming - doesn’t each tractor model start at roughly the same pressure? I’m assuming the pressure is based off the opening size. It seems logical that there would be a certain size crates certain pressure so you could just buy one that is designed for 1100 or whatever. Or is there some sort of dilating orffice that allows some regulation despite the shim size? Yes, a tractors hydraulic relief pressure is set from the OEM. Shimming a relief valve spring increases the hydraulic relief pressure. Some reliefs are adjustable but most need to be shimmed if you need to increase the pressure. It is never a good idea to increase the hydraulic pressure higher than the design hydraulic pressure. Check the relief pressure first to verify it is within spec. If it is, then do not mess with it.

Cut off - now I understand what it does (isolation of an unused supply essentially). Why would this nit be included if you bought a machine with a blower or plow? Does this mean my new machine will be trying to actuate my blower lift and another unused line? I’m still a little lost here. Essentially, JD uses the same function control to control two different attachments, e.g. mmm lift and blower chute rotation. They tee them together so when the blower is being used, the needle valve must be closed to block the flow to the mmm lift cylinder.

Thanks in advance if you can shed additional light.

Chris
See red letter response above.
 

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Hey all,

I have gone through every thread and I can’t find anything about hydraulic shimming that explains or shows what is being done. A lot of posts saying the did it, or the did this size whatevers, or how much psi. I have no idea where a shim goes, how many are required, anything.

I have a new toy coming and I am planning on getting a fel for it. I am really curious where this shim goes on a x739. Is there one per hydraulic line?

While I’m at it.... lock outs? Why, where, when are they used. Again a lot of posts says installed lockout all good now. Sorry nit helpful to newbies to hydraulics.

Any simple information you can share or point me at?

Thanks
The Deere x7-series tractors have two hydraulic circuits - one related to each of the levers to the right of the steering wheel. One of the two circuits routes fluid to the mower deck lift. This one benefits from a valve that can be turned to prevent fluid from going into that part of the system when you don't have the deck on. That way full fluid flow can go through the right-side mounted SCV ports to whatever you are using connected to them (often a snowblower with lift and chute rotation). If you don't have a diverter valve then that circuit will have slower response and won't be as effective with your front implement. This valve comes with some of the front implement kits, though I'm not 100% sure which ones. Definitely the snowblowers.

Plus the situation mentioned elsewhere here about the draft arms moving if you don't use the diverter and don't lock them up with the storage latch. But most people latch the arms up when using a front-mounted implement so that's not really a normal problem.

Rob
 

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Ill second what Ray PA said.

Just to attempt to add a bit more clarity:

"Shimming" may not really involve shims at all.
On my 318 I shimmed the relief valves to increase operating pressure. I did not go crazy with it, as I just wanted a tad more. I think it added 50 psi. 900 overall if I recall, but its been quite a while.
On that one, there were several threads about the process, and showing the location of the shims and how to do it. Im also very handy, and do many repairs to vehicles/equipment that scare the begeezes out of even some people that think they too are pretty handy.
On the 2025, I was looking into "shimming" the relief valve for the loader, so I could get a bit more oomph out of it. It took quite a while, and in the end, I just had to tear into it and find out what was what. On that one, I did increase it, but only to the max limit within spec, as it was quite a bit below it from the factory.
That one required no shims and was a simple adjustment on the valve, once I found it, and since Id done several similar adjustments on other valves of different types, this was easy.
Had I never done one before, Im not sure now that I could have figured out the proper way to do it without asking.
My guess is that your new tractor will have a similar relief valve that can be adjusted without shims, but Ive never seem the X series, so I cant say with any certainty.

The lock out valve is something helpful only in very specific circumstances.
On the 318, and several other tractors, one hydraulic spool controls 2 different functions, but this is normally not an issue.
On the 318, the deck lift is the same mechanically as the rockshaft/3-point. This circuit is also one set of front ports.
Normally, this is a non-issue.
The trouble comes, generally, in the Winter when you have the 54 blade attached.
When you go to angle the blade, in factory condition, you have to wait for the rear cylinder to finish its cycle before you get much pressure to the front. It doesnt effect much, other than the time it takes to complete a job, but can be frustrating if you angle the blade back and forth a lot.
The lock out is simply an in-line valve that shuts off flow to the cylinder its connected to or in-line with.
On the 318, I set the rear 3-point stop where I want the weight resting, then turn the valve shutting off that part of the circuit.
This makes the blade angle react instantly instead of with a long delay.
Again, Ive never seen the X series hydraulics, so I cant say one way or the other if it would be helpful to add one.
Youll know if its necessary once you start using it.
 

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In case it helps, my 1994 425 had about 700 psi available when I got it. For that unit you apply the shims under the relief valve and I used a combination of 10mm x 5mm x .3mm and .5mm and brought the pressure up to about 1200 which helped a lot for the FEL. But when I was doing the shimming I noticed the piston in the relief valve was worn which made me wonder if the spring had also become weak - it was 20+ years after all. So I ordered a replacement relief valve from Tuff-Torque directly. What a difference - pressure without any shimming was 1000 and I added just a single shim to get it to around 1250 which served me well and I considered safe.
 

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Hey all,

I have gone through every thread and I can’t find anything about hydraulic shimming that explains or shows what is being done. A lot of posts saying the did it, or the did this size whatevers, or how much psi. I have no idea where a shim goes, how many are required, anything.

I have a new toy coming and I am planning on getting a fel for it. I am really curious where this shim goes on a x739. Is there one per hydraulic line?

While I’m at it.... lock outs? Why, where, when are they used. Again a lot of posts says installed lockout all good now. Sorry nit helpful to newbies to hydraulics.

Any simple information you can share or point me at?

Thanks
Since you plan on getting a loader for your X739 Your Going two need to get two Parts from Deere

BW15044 TRANSAXLE HYDROSTATIC RELIEF VALVE 4WD or AWD $161.57 this is the Valve You shim This Valve Protect your transmission from Pressure Peaks associated with use of the Loader

M146148 free-wheeling valve control lever is also required $14.29

I Take it You Plan On Buying one of these 2013 John deere x ultimate

The Lockout Valve diverts Hydraulic Fluid towards the hydraulic outlets Instead of the tractors on board Hydraulic cylinder when closed. When Open hydraulic fluid freely flows to the on board Hydraulic cylinder as well as the outlets
:bigthumb:
 

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I shimmed my 790 as well as my cousin’s. Checked pressure with gauge and they both were around 2200psi. Added 4 shims to relief valve and bought pressure up to 2800 psi. Noticeable difference. Shim kit bought from Green Farm Parts. Kit had 4 shims included and on the 790, read to keep them at 2900psi or lower so you don’t hurt the pump. Again can tell improvements with more pressure and was worth the increase. 790 are easy as relief in right under the seat.
 

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Since you plan on getting a loader for your X739 Your Going two need to get two Parts from Deere

BW15044 TRANSAXLE HYDROSTATIC RELIEF VALVE 4WD or AWD $161.57 this is the Valve You shim This Valve Protect your transmission from Pressure Peaks associated with use of the Loader

M146148 free-wheeling valve control lever is also required $14.29

I Take it You Plan On Buying one of these 2013 John deere x ultimate

:bigthumb:
Hey, Sergeant, did you type that right? I think you meant to say that the THRV is NOT the valve that you shim and that you instead shim the IRV.

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Discussion Starter #16
Just for clarification, if I add a loader and am happy with the lift performance (as is) do I still need to make any modifications to protect my hydraulic system?
 

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You need to add the THRV to prevent damage to the transaxle when under load with the loader. Shimming is an optional performance boost that many folks never bother with.

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Discussion Starter #18
I am getting some conflicting information from two different Deere techs. One stated that the k90 is equipped with a THRV OEM. The other said it was not. I contacted the transaxle manufacturer Tuff-Torq. I'll follow up with their response for any future interest.
 

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I am getting some conflicting information from two different Deere techs. One stated that the k90 is equipped with a THRV OEM. The other said it was not. I contacted the transaxle manufacturer Tuff-Torq. I'll follow up with their response for any future interest.
My bad for saying "add". Yes, a THRV is already present. You need to upgrade the THRV. The one installed at the factory is not rated for the stress levels that use of the loader can add on firm surfaces.

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Discussion Starter #20 (Edited)
My bad for saying "add". Yes, a THRV is already present. You need to upgrade the THRV. The one installed at the factory is not rated for the stress levels that use of the loader can add on firm surfaces.

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Super thankful for the patient replies. I get the requirements. One more question that maybe someone has seen. My Greene machine has a K90 Transaxle. I am assuming (or should I?) that all K90's would take the same THRV and Free wheeling bar. Is there a list somewhere that shows what tractors have the K90's? I have seen a lot of posts about this upgrade but not sure if they are the same transaxle as the x739.

Thanks
 
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