L345DT hydraulic problems

[Carlaisle]

Greetings...new arrival here.

I have an L345DT I acquired very used, although not obviously abused. Tach cable was broken when acquired, so it definitely has over 2,000 hours on it, but how many more than that is unknowable. It started right up and everything worked well except the crunchy PTO bearing that I replaced shortly after acquisition.

The problem I'm asking about did not manifest until after I had a chance to get it well up to temp and work it a bit. Until things get up to operating temp the hydraulics have full power and speed seems appropriate. As the machine - and the hydraulic fluid - becomes warmer, the hydraulics slow until they quit working completely. i.e. 3 point and loader cylinders and power steering eventually become completely unresponsive. Go take a break long enough for things to materially cool down, and everything works again. Fluid levels for both power steering and transmission were correct.

I pulled the hydraulic filter and found it installed incorrectly - the spring that keeps it compressed to the housing was laying in there sideways. I cleaned a bunch of fine aluminum debris (or other shiny non-magnetic bits) off the screen and some smaller (BB size) chunks and reassembled it correctly with no improvement. I'm guessing the pump cases and/or gears are worn, but am leery of disassembling them lest any parts or gaskets be unavailable. The only place i can take it apart under a roof it will be in the way, so I don't want it to be rooted in place indefinitely. I see the full pump is an available part, but for that asking price I could take a pretty nice vacation.

I searched around here and there seem to be some fairly knowledgeable people, so I thought I would ask if any of you would share your thoughts and advice.

 

[TheOldHokie]

Greetings...new arrival here.

I have an L345DT I acquired very used, although not obviously abused. Tach cable was broken when acquired, so it definitely has over 2,000 hours on it, but how many more than that is unknowable. It started right up and everything worked well except the crunchy PTO bearing that I replaced shortly after acquisition.

The problem I'm asking about did not manifest until after I had a chance to get it well up to temp and work it a bit. Until things get up to operating temp the hydraulics have full power and speed seems appropriate. As the machine - and the hydraulic fluid - becomes warmer, the hydraulics slow until they quit working completely. i.e. 3 point and loader cylinders and power steering eventually become completely unresponsive. Go take a break long enough for things to materially cool down, and everything works again. Fluid levels for both power steering and transmission were correct.

I pulled the hydraulic filter and found it installed incorrectly - the spring that keeps it compressed to the housing was laying in there sideways. I cleaned a bunch of fine aluminum debris (or other shiny non-magnetic bits) off the screen and some smaller (BB size) chunks and reassembled it correctly with no improvement. I'm guessing the pump cases and/or gears are worn, but am leery of disassembling them lest any parts or gaskets be unavailable. The only place i can take it apart under a roof it will be in the way, so I don't want it to be rooted in place indefinitely. I see the full pump is an available part, but for that asking price I could take a pretty nice vacation.

I searched around here and there seem to be some fairly knowledgeable people, so I thought I would ask if any of you would share your thoughts and advice.

Pretty common and simple. Hot oil is less viscous than cold oil. That means it requires tighter clearances to generate hydraulic pressure. Based on the fact that all of your systems exhibit a problem suspect #1 is your hydraulic pump. Its likely worn out and loosing pressure when the oil heats up. Time for a pressure test but I am pretty sure I can predict the result. Good news is a new pump is not expensive and its relatively easy to replace.

Whoops- after looking might be more expensive than I thought.

Dan

 

[D2Cat]

Welcome. Might look up "007kubotaguy" on this forum. He has access to older Kubota "L" series tractor parts and is very familiar with those tractors. He can give advice applicable to your machine and perhaps have what you need in parts.

 

[007kubotaguy]

As Dan said you have all the signs of a wore out hydraulic pump. Fluid gets hot and it doesn't pump. Your tractor has a dual pump setup. One pump for the power steering one pump for the tractor hydraulics. You have a separate Reservoir for the power steering which is on top of the engine. I would be concerned about the metal that you have found in the system. One Source that comes to mind is the brakes. You have wet brakes and when the disc wears out you end up with metal to metal. The metal gets in the system and can wear a hydraulic pump out real fast. I do have lots of used parts for your tractor. I would have a good used hydraulic pump.

 

[North Idaho Wolfman]

I think it's odd that he's loosing both the hydraulics and the PS as they are 2 separate loops and 2 separate systems, I could see loosing one or the other but both seams odd?
Maybe the main pump is heating up enough to effect the PS pump?

 

[007kubotaguy]

I think it's odd that he's loosing both the hydraulics and the PS as they are 2 separate loops and 2 separate systems, I could see loosing one or the other but both seams odd?
Maybe the main pump is heating up enough to effect the PS pump?

That is odd if they are failing at the same time. The power steering pumps on these units seem to last forever. They don't get any contamination in them from the powertrain. I have replaced lots of the main pumps but very seldom a power steering pump.

 

[Carlaisle]

I appreciate all of the replies. The metal bits seem unlikely to have materialized out of thin air, so identifying their source and repairing the cause seems the most prudent first step. I did not consider the brakes as a potential source. The entire hydraulic system must be contaminated with abrasive gremlins. Any recommendations on how to evict the grit?

These brakes do not appear designed for the same ease of maintenance as those on the average automobile. It looks like I'll have to do basically the same work to inspect them as would be required to replace them. Is there anything I should know before digging in? It looks like every part that could be needed for the brakes is readily available.

007kubotaguy, I expect I'll be in touch about the pump when I make it to that point. You wouldn't happen to have a hood, would you? I have one, but it looks like someone dropped a tree on it and then tried to fix it with a pick axe. That may be a slight exaggeration, but only slight.

 

[Russell King]

To get the grit out of the system is fairly straightforward. Drain the fluid. Take out the screen and filter and replace them. Replace the fluid.

@007kubotaguy or @North Idaho Wolfman:
Could the gears of the transmission be the source of the metal if they are chipped or have been ground to death?

 

[North Idaho Wolfman]

@007kubotaguy or @North Idaho Wolfman:
Could the gears of the transmission be the source of the metal if they are chipped or have been ground to death?

It could but the filter should pull it out.
If I had an issue, I personally would install a magnet to pull any magnetic material out of the fluid.

 

[North Idaho Wolfman]

Carlaisle, Are you sure your losing power steering as well as all the other hydraulics?

 

[Carlaisle]

Am definitely losing power steering at the same time. Attempting to steer even with an empty bucket and no power steering gives a very distinctive work out.

The magnet is a good idea, but some of the metallic bits were not magnetic. Where do you think would be the best place for the magnet? On the filter housing, drain plug, other? In searching the forum I saw a member who installed a spin on filter and housing in place of the factory one. Do you think that would be a good temporary measure to help clean things out? It could also be a permanent measure if it's a material improvement. I don't know what filtration level the factory filter screen provides, so it might not represent any improvement.

 

[Russell King]

I pulled the hydraulic filter and found it installed incorrectly - the spring that keeps it compressed to the housing was laying in there sideways.

@North Idaho Wolfman … filter was probably not filtering the fluid at all.

 

[North Idaho Wolfman]

@North Idaho Wolfman … filter was probably not filtering the fluid at all.

I missed that, would explain the main pump failure.
Still leaves the PS pump failure unexplained.

Am definitely losing power steering at the same time. Attempting to steer even with an empty bucket and no power steering gives a very distinctive work out.

The magnet is a good idea, but some of the metallic bits were not magnetic. Where do you think would be the best place for the magnet? On the filter housing, drain plug, other? In searching the forum I saw a member who installed a spin on filter and housing in place of the factory one. Do you think that would be a good temporary measure to help clean things out? It could also be a permanent measure if it's a material improvement. I don't know what filtration level the factory filter screen provides, so it might not represent any improvement.

I would replace the original filter with a spin on filter with a magnet.

You do understand that 2 pumps failing at the same time that have 2 separate fluid paths that are not connected is rather odd.
Have you checked the fluid level for the PS?

 

[Carlaisle]

I agree two pumps failing simultaneously that have no shared fluid between them is very unusual. In fact, I don't see where it makes any sense at all.

I did check the power steering fluid level. It was full. The diagram of the power steering circuit does not show any filtration or a pressure relieve valve, which also seems unusual.

 

[North Idaho Wolfman]

I agree two pumps failing simultaneously that have no shared fluid between them is very unusual. In fact, I don't see where it makes any sense at all.

I did check the power steering fluid level. It was full. The diagram of the power steering circuit does not show any filtration or a pressure relieve valve, which also seems unusual.

No filter, the power unit has the relief valve built into it.

One thing that could be going on is that they both share the same drive.
If the drive is damaged I could see how it's effecting both pumps.

It might be a great idea if you pulled the pumps and checked the drive out.

 

[Carlaisle]

What could be affecting the drive that would result in things working correctly when cool but ceasing to work entirely when warm?

 

[TheOldHokie]

What could be affecting the drive that would result in things working correctly when cool but ceasing to work entirely when warm?

Does not seem likely.

Dan

 

[rbargeron]

A long-shot possibility is if the prior owner put the wrong fluid in the tractor? Does it seem like regular hydraulic oil ? Should be like syrup. If it seems too thin, a reasonable experiment would be to drain just the power steering reservoir - and put in a couple quarts of straight 30w motor oil. Test it for a while to see if the steering is any better. As others have said, its odd that two not-connected systems would be weak.

 

[North Idaho Wolfman]

What could be affecting the drive that would result in things working correctly when cool but ceasing to work entirely when warm?

I've seen one setup that had stripped splines on the drive, that one would work fine till it got a heavy load then would simply stop.

 

[Carlaisle]

I'll pull the pumps and report back on the findings.