Possible to regulate 3pt hitch lift rate? (YM186d)

[oldgrayfellow]

Not wanting to hijack the other threads, opened a new one..

Also the YM186 (D) lift is too energetic to make subtle adjustments. I could adjust the drop valve to go down slowly, but lifting the blade when it dug too hard was sudden and extreme with no way to feather it.

Yes i noticed that too-- sure would be nice to be able to adjust this. The 3pt on mine pretty much SLAMS my tiller to the up position. Think this may have even caused a previous problem with dislodging a retaining ring inside the PTO.

California, i guess you are saying that turning down the stop valve (even to almost closed) has no effect on the 3pt raising speed (but only on the drop speed)?

I would have thought otherwise.. (though i haven't tried it). From the 186d service manual they have a section on measuring raising performance of the lift. (Hydraulic lift cycle test time)
They say to put 550lb of weight on the 3pt, then check the lift time for the complete stroke (it should be 2.0 seconds). If it does not meet specs. the first thing they say is to "Check if the stop valve is completely opened".
This suggests that adjusting the stop valve could regulate raising speed.

Puzzled...

 

[oldgrayfellow]

Now i see in the operators manual that the "stop valve" is separate from the "slow return valve".
The slow return valve is expressly designed to regulate speed of drop (only).

The stop valve is designed to lock the lift in a specific position. They do not mention using it as a way of regulating the lifting speed, but they do say not to pull the control lever to raise the lift when the stop valve is closed, and also to open the stop valve completely when it is not in use.

Trying to raise with the valve completely closed is a no-no... maybe this would "dead-head" the hydraulic pump? But what about if the valve is only partially restricted-- is this permissible? (It would seem that reducing flow through the stop valve ought to be a way of restrict the raising rate, if it doesn't hurt the pump)?

 

[winston1]

I've read you are not to use the stop valve for adjusting the drop speed but I shall confess to you I do on my 2002d. It does not have any effect on the raise speed. I do believe that "slowly" moving your 3 point lever up or down does make for a slower raise or drop speed.

 

[deepNdirt]

Yes I have only found the adjustment on the lowering speed, Usually the lift speed depends on the RPM of the tractor and how fast the pump can circulate the fluid to build lift pressure, the lowering on my tractor is gravity fall and the adjustment simply restricts and slowes down the fluid so that it won't slam down,Via" gravity)... I have and does seem that I can adjust the lock valve to slow the lift somewhat, although I notice if I need it to go any slower I'll simply lower the running speed of the tractor,....... this is my 1700
Now on another tractor I had ( Kubota ) it had 2- T valve's .one to adjust the Lowering rate and adjust the lift rate,

 

[California]

My YM240 (YM2000) and my YM186D have totally different lift linkages. I think the internals are designed different too.

The YM240 lifts at moderate speed. With a cautious touch on the lever, I can use the lever to grade a reasonably flat surface.

The little tractor works differently. It is impossible while moving over a surface that needs grading, to move the lift lever gently enough to grade a smooth line. At the slightest touch the 3-point lifts violently. I don't think I've ever stopped the lift at less than 3 inches no matter how much I concentrate on a gentle touch, at least while moving.

Yes, the drop rate valve can be set to lower the 3-point gracefully, also the service valve (not recommended). But I haven't found a way to raise the blade gently.

 

[renter damaged uhoh]

My crude guess is the lift rate is dependant on the pump speed. If their was external hoses then perhaps a restrictor could be utilized.

The down rate is not dependant on a pump and instead is based on gravity. Just like a floor Jack.

I subscribed to he thread since my main purpose of the tractor is to level my back yard.

 

[clemsonfor]

If this is the case, why is there a lever on the side that you can go through the motion with, why is it not easily controled by the valve? Did they just cobble togeather parts from other tractors at the factory and not engineer them to work togeather. This seems like this is a pretty sorry setup, esp since this is the american version of the tractor not just a japaneese model whose sole job is to till up rice fields, tiller up/tiller down.

 

[JCByrd24]

Hi guys, new here, just bought a 186D two weeks ago. Loving it so far. I've noticed the exact same thing, very hard to regulate the up speed with the detented valve. Very fast and jerky when running at rated speed. I've been on a mission to try to figure out the whole hydraulics system after reading about the pump failures due to deadheading and this is also on the list of little things to figure out. I don't know why such a strongly detented valve was used in the up position instead of a valve that can be regulated. What is happening is that the valve pops easily to the lift position, not bypassing any fluid in the open center portion. Hydraulic pumps are almost always the positive displacement type, which means they will push the same flow rate regardless of the pressure, until whatever is driving the pump (yanmar diesel) stalls or something breaks. Once that detent is hit all flow is going to the lift cylinder. This is why the lift speed is related to engine speed, more RPM equals more flow. Closing the stop valve will not really help, it will just raise the pressure and work the pump and engine harder, the flow is basically the same which means the speed is the same. What we need is a flow controlling device, such as this:
BRAND Hydraulics Full Range Pressure Compensating Variable Flow Control
I have a loader, so this would be plumbed in between the loader valve power beyond and the 3PH hydraulics. It will basically dump a certain amount of flow to the tank while the 3PH hydraulics are activated. Another nice feature of this particular one is you can get a built in relief valve. Another thing I can't figure out is why the yanmar relief is downstream of the stop valve and the loader relief doesn't protect the whole circuit, just the loader cylinders.

Anyway, long thread, glad to find the site.

 

[Pete Judd]

I have the same problem with my 186d I have a 5 foot brush hog on the back and if I am not careful it will raise the the front wheels off the ground real quick. I have gotten a lot better at the lift lever. But at 2400 rpm, I moves up real fast.

 

[winston1]

quote jcbyrd24 "Another thing I can't figure out is why the Yanmar relief is downstream of the stop valve". On my 2002 and also the 220/226 American sold the capability to install a remote hydraulic port could be the reason why the relief valve is on the down side of the stop valve. I have one installed on my 2002 that operates a single acting cylinder on a 3 point cement mixer. To operate it I simply raise my lift to desired height, close stop valve and fluid flow is then diverted to remote. I can then tilt mixer up or down while 2 point stays at set level. I don't have a clue what all models have this feature, when I was looking for a way to operate my mixer I came on it in the repair manual. This wouldn't work without the relief valve on the down side of the stop valve. JCByrd, if you decide to install that flow control valve I would be interested in the results. Am I right in thinking these valves are in the $100 range?