Aaargh! 3-pt hitch not lifting any weight.
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J_J
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The parts that were stuck in the assembly, was that the flow control for the 3pt valve or the valve that controls the descent rate?
J_J
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When you screw in the knob for the 3pt lock, are those parts involved?
I am guessing that the valve got stuck in the valve housing, and blocked the flow into the 3pt cyl.
In post #68, upper right, that appears to be the 3pt spool, so it looks like the other parts should be the flow control for the descent valve
I am guessing that the valve got stuck in the valve housing, and blocked the flow into the 3pt cyl.
In post #68, upper right, that appears to be the 3pt spool, so it looks like the other parts should be the flow control for the descent valve
Leejohn
Elite Member
That part he is showing is just a plug and when it was put together the oring got cut and just now broke all the way loose, then got stuck in the little spool.
J_J
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The flow control valve appears to be spring loaded, and I can almost bet that the end of the screw, presses on this part to push in on the valve and regulate and close off the flow to the 3pt. The o-ring is there to seal off the fluid.
My thoughts on the 3pt valve is this. The 3pt lever controls the amount of fluid going into the 3pt cyl, and the flow control valve controls how much is allowed to flow out of the cyl.
If the flow control valve is closed, will the 3pt lever allow the 3pt to operate at all or just one time, to raise the 3pt, but not lower until the knob releases the fluid.
{ Response control. Response control (in most systems we know of) simply serves to control the rate at which hydraulic oil is allowed to escape from the lift cylinder. By slowing this rate, we minimize undesirable oscillations that would otherwise occur. Response control has no effect on rate of lift, and that is good, because we want the plow to raise quickly when we hit a hard spot. However, if we let the plow go back into the ground at an uncontrolled speed, we will end up pulling a plow that jumps into and out of the ground. We have to give the system a little time to settle down somewhere in the raise/lower cycle, and that is the function of the response control.
If lower is selected, the oil from the pump is directed, by the control valve, to the reservoir (just like neutral); however, a passage is also opened which will allow oil to escape from the lift cylinder, allowing gravity to lower the lift arms. Many of the smaller compact tractors are, in fact, just that simple in lift control. }
Any other thoughts on this?
My thoughts on the 3pt valve is this. The 3pt lever controls the amount of fluid going into the 3pt cyl, and the flow control valve controls how much is allowed to flow out of the cyl.
If the flow control valve is closed, will the 3pt lever allow the 3pt to operate at all or just one time, to raise the 3pt, but not lower until the knob releases the fluid.
{ Response control. Response control (in most systems we know of) simply serves to control the rate at which hydraulic oil is allowed to escape from the lift cylinder. By slowing this rate, we minimize undesirable oscillations that would otherwise occur. Response control has no effect on rate of lift, and that is good, because we want the plow to raise quickly when we hit a hard spot. However, if we let the plow go back into the ground at an uncontrolled speed, we will end up pulling a plow that jumps into and out of the ground. We have to give the system a little time to settle down somewhere in the raise/lower cycle, and that is the function of the response control.
If lower is selected, the oil from the pump is directed, by the control valve, to the reservoir (just like neutral); however, a passage is also opened which will allow oil to escape from the lift cylinder, allowing gravity to lower the lift arms. Many of the smaller compact tractors are, in fact, just that simple in lift control. }
Any other thoughts on this?
Last edited:
Leejohn
Elite Member
( The flow control valve appears to be spring loaded, and I can almost bet that the end of the screw, presses on this part to push in on the valve and regulate and close off the flow to the 3pt. The o-ring is there to seal off the fluid. )
I think hyd oil moves that spool open and closed. What screw are you taking about? If you mean the push pin that goes into another hole altogether.
( { Response control. Response control (in most systems we know of) simply serves to control the rate at which hydraulic oil is allowed to escape from the lift cylinder. By slowing this rate, we minimize undesirable oscillations that would otherwise occur. Response control has no effect on rate of lift, and that is good, because we want the plow to raise quickly when we hit a hard spot. However, if we let the plow go back into the ground at an uncontrolled speed, we will end up pulling a plow that jumps into and out of the ground. We have to give the system a little time to settle down somewhere in the raise/lower cycle, and that is the function of the response control. )
Where did you find this or can you put the link to it? I would like to read all of it, if there is more to read.
I think hyd oil moves that spool open and closed. What screw are you taking about? If you mean the push pin that goes into another hole altogether.
( { Response control. Response control (in most systems we know of) simply serves to control the rate at which hydraulic oil is allowed to escape from the lift cylinder. By slowing this rate, we minimize undesirable oscillations that would otherwise occur. Response control has no effect on rate of lift, and that is good, because we want the plow to raise quickly when we hit a hard spot. However, if we let the plow go back into the ground at an uncontrolled speed, we will end up pulling a plow that jumps into and out of the ground. We have to give the system a little time to settle down somewhere in the raise/lower cycle, and that is the function of the response control. )
Where did you find this or can you put the link to it? I would like to read all of it, if there is more to read.
J_J
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I am talking about the knob that screws in to regulate the descent rate.
My theory is an educated guess.
Here is the data, with explanations of other 3pt stuff.
http://www.tractorsmart.com/main/Tractor Three Point Lift Types.htm
http://www.tractorsmart.com/enter.htm
Select Info
My theory is an educated guess.
Here is the data, with explanations of other 3pt stuff.
http://www.tractorsmart.com/main/Tractor Three Point Lift Types.htm
http://www.tractorsmart.com/enter.htm
Select Info
Leejohn
Elite Member
1st thanks for the link JJ. After reading it I understand it more. The way I see how it works is, the response control valve (spool) is always working and it shines if you have draft control. By just slowing down a load and the knob on the rockshaft lets you over ride it. Now I can see why if the spool is open (with part of the broken oring) the 3pt would not lift.
