My Ford 1910 bounces when I lift an implement on the 3-pt hitch and the front loader operates a little slow. I just replaced the hydraulic oil filter and I just replaced the U seal on the hydraulic piston, which was in bad shape. The hydraulic oil level is overfilled, but I don't see any evidence that this could cause the problem. The service manual is NO HELP at all in troubleshooting this. Anybody know what the problem could be? I'm stumped because I really thought that replacing the bad seal would fix it.
Help! Tractor bounces with implement raised.
oldnslo
Super Member
Does the 3 point lift in jerky movement and then hold position or is it drifting down and then lifting back up?
If I raise the implement off the ground, regardless of how high I raise it, the tractor bounces real bad. It will hold that position but with bouncing. Something important that I forgot to mention is that although I just replaced the seal on the hydraulic piston, the implement lowers to the ground when I turn the tractor off (and yes, I installed the seal in the correct direction with the U facing the front of the tractor). This makes me wonder if something is wrong with a valve or something.
oldnslo
Super Member
what was the reason you replaced the lift cylinder seal? Did the old one look bad when you removed it?
Not familiar with your tractor but did you have to dismantle the valve and connecting linkage to repair the cylinder? If yes is that all reassembled and adjusted correctly?
Air would make it bounce but cycling 3 point a few times should have removed air from the circuit
Not familiar with your tractor but did you have to dismantle the valve and connecting linkage to repair the cylinder? If yes is that all reassembled and adjusted correctly?
Air would make it bounce but cycling 3 point a few times should have removed air from the circuit
rScotty
Super Member
- Joined
- Apr 21, 2001
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- 9,473
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- Rural mountains - Colorado
- Tractor
- Kubota M59, JD530, JD310SG. Restoring Yanmar YM165D
Does turning the drop speed adjustment knob under the front of the seat change anything?
It is possible that valve needs new seals. If the seals are shot, that valve could be letting out of the 3pt hydraulic cylinder almost as fast as the pump can replace it.
I've read the service manual and don't see anything about bleeding air out of the lift cylinder. Is this something you've done before?
I replaced the cylinder seal thinking it would solve this problem of the tractor bouncing and the 3 point implement dropping after shutting the tractor off. I was surprised to see that a brand new seal didn't help the problem at all because the seal was almost completely disintegrated. Replacing it was very simple and I didn't have to mess with any linkages or valves or anything - the cylinder assembly just slides out with the flow control valve plate under the seat. I'll cycle the 3 point up and down a few times and see if anything changes.
Yes it does. Let me give you the details. If I lift the implement up, it bounces like crazy (shakes the tractor vigorously) until I turn the flow control knob all the way off and then it doesn't bounce at all. If I turn the tractor off and leave the flow control knob all the way closed, my blade stays up now without creeping down, so the new seal fixed that problem. But, if I turn the tractor off and then open up the flow control knob, the blade drops to the ground. I tried posting some videos but they're not allowed. Which valves are you thinking of: the flow control valve assembly or the 3 pt lever control valve assembly? I attached assembly views of both valve assemblies.
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rScotty
Super Member
- Joined
- Apr 21, 2001
- Messages
- 9,473
- Location
- Rural mountains - Colorado
- Tractor
- Kubota M59, JD530, JD310SG. Restoring Yanmar YM165D
The flow control knob when it is operating correctly only controls the speed of the drop of the 3pt arms. It is for drop rate only. Your 3pt cylinder sounds like it is losing fluid and then refilling. That could be due to the drop rate knob being bypassed internally because some of the O rings on the drop rate shaft are missing.
It could also be due to the main 3pt lifting valve stop being missing or misadjusted. More about that below.
The new seal - I assume you mean the piston seal - sounds like it fixed the problem of fluid bypassing the piston-to-cylinder walls. But that new seal doesn't do anything for the other leakage path past the drop rate knob O rings.
Maybe both. The drop rate knob is easy to remove and service. Basically a long needle valve with some O rings on it. The only reason I suggest that drop rate knob at all is because it could cause that problem and it is easy to R&R. Always do the easy things first.
If yours has an internal cleanable crud filter screen in the hydraulic sump make sure that is clean. Often overlooked & could also cause the problems you have. I think the older Fords have that screen.
Frankly, yours sounds to me more like the 3pt lever control assembly is out of adjustment. Or a relief valve is stuck open....can you hear anything? The control \could even be missing one of the springs or nuts that adjust spring preload on the main lever control assembly. That happens so rarely that most mechanics - including myself - rarely adjust one. I'd probably start by comparing all the external springs and nuts with a known good one.
Here is a general overview of how any 3pt hitch operates:
luck,
rScotty
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