3-Point Hitch Hydraulic lifts slowly drop over night
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LD1
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Gentlemen, I was noticing that the rear lift of my TC40A has been dropping over nights. I recently(2 days ago) changed the hyd filter is it possibly loose or something? Don't see any leaks from filter. Any suggestions?.. Is this normal after a filter change?
A certain amount of drop is usually acceptable due to a little but of fluid weeping aroung the seals and such. But that is usually only with a heavy implement on.
The pic you took just shows an empty 3PH. Is it bleeding down with nothing on??? if so that is a problem. No more than the arms weigh, it should be able to hold them up for a long time with no drift at all.
How many hours are on the machine??
ArtMech
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Gentlemen, I was noticing that the rear lift of my TC40A has been dropping over nights. I recently(2 days ago) changed the hyd filter is it possibly loose or something? Don't see any leaks from filter. Any suggestions?.. Is this normal after a filter change?
Is that tractor just obtained? I mean have You checked whether the lifting arms had some amount of drop before filter change?
Jerry/MT
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Gentlemen, I was noticing that the rear lift of my TC40A has been dropping over nights. I recently(2 days ago) changed the hyd filter is it possibly loose or something? Don't see any leaks from filter. Any suggestions?.. Is this normal after a filter change?
A little leak down is normal. The hydraulic filter is normally on the suction side of the pump and the lift cylinder is after the pump and is usually checked so I doubt that the filter has anything to do with it. I'm assuming you tightened the filter down per the instructions. If it leaks I suppose it could suck air in which might foam and cause some settling if it's in the cylinder but that usually cause a noisy pump when there is air entrained.
There could be some seal leakage in the lift cylinder or in the relief valve or the check valve, etc. Put some load on it and raise the arms up completely and then shutdown and see how long they take to drift down completely. that will give you an idea of the magnitude of the leakage. If you know the cylinder diameter and the stroke you can calculate the leakage rate. [ Leakage rate ~gallons per minute = (pi * D^2*Stroke)/(4*delta t* 231.) where pi = 3.14159, D is the cylinder diameter~inches, L is the stroke~ inches, and delta t is the time~minutes it takes to fully drop.]
Soundguy
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yep.. all possible. and if it takes all night to do so.. it's not really a problem.. not even a nusiance really. just something to keep in mind.. betweent he piston seal, check, relief and spool.. you can't expect them to all be 100% efficient... something, somewhere is gonna leak a lil.. should be expected.
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Gentlemen, I was noticing that the rear lift of my TC40A has been dropping over nights. I recently(2 days ago) changed the hyd filter is it possibly loose or something? Don't see any leaks from filter. Any suggestions?.. Is this normal after a filter change?
As someone else said, there is no way for a filter change to have this effect on your 3PH. What you need to check is if it is the lift cylinder or the HPL valve leaking. Lift the 3PH all the way to the top and then adjust your drop speed needle valve under the seat all the way clockwise so the needle valve is closed. If the arms drop, it's either a leaking lift cylinder (most likely) or the overpressure relief valve (not likely). If the arms do not drop unless the needle valve is open, then the problem is probably in the HPL control valve that you set with the lift lever on the right fender. By using the drop speed needle valve you can eliminate a lot of the system.
This morning, I lifted the 3PH all the way and turned the drop speed needle, photo attached, valve clockwise until it stopped turning, closing it completely. But it still dropped half way after 5hrs. I still don't see any leaks anywhere, photos. If the lift cylinder is leaking would I see the leak?
Oh, by the way where is the lift cylinder? Sorry for the inexperience....
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JC-jetro
Elite Member
Jim,
There are two ports where hyd fluid enters the lift cylinder as the diagram shows. One is thru the needle valve and second is thru a ball check with a light spring. That would allow the return to spool valve only thu the needle valve unless middle check is not holding.
There is potential for drop even with a tight and closed needle valve due to potential leaky check valves, The position of needle valve has no effect on fluid flow passage thru the check valve.
Over pressure small ball and stiff spring on the right and normal flow to the cylinder with big check ball and not so stiff spring.
I think all I have seen on my 1700 to any TC series shibaura uses exact the same design.
JC,
JC-jetro
Elite Member
Gentlemen, I was noticing that the rear lift of my TC40A has been dropping over nights. I recently(2 days ago) changed the hyd filter is it possibly loose or something? Don't see any leaks from filter. Any suggestions?.. Is this normal after a filter change?
You might refer to attached pdf for the answer to your question.
JC,
I think the most likely culprit amongst the others is leaky piston seal that will be your cheapest and easiest fix considering the design.