L345DT No Hydraulic Pressure

[RoverDog]

My landlord has an L345DT with FEL and mower on the 3-point hitch that he mostly uses a few times a year to mow the weeds on his (our) property. He last used it about 6 weeks ago and it worked fine, today he fired it up and the hydraulics wouldn't work, neither the FEL or the 3-point. There's just no movement whatsoever. I've looked at it, read through some similar problems here and tried a few things, no luck. So here's what I've done: Checked the power steering, which works fine so the pumps are apparently both turning, checked hydraulic fluid level, added maybe 1/2 qt. Tapped on the pressure relief valve, opened the valve up and checked for a stuck plunger, all seems okay there. Opened the filter housing, removed, checked and cleaned the filter screen (it wasn't plugged). Checked the short hose on the supply tube just before the filter, replaced one bad clamp. Removed the inlet fitting from the filter to the top of the pump and filled the pump with oil, it only took a few ounces. Did this twice. I've also cracked a couple lines and gotten no fluid out of them, other than residual dribble. Still nothing after every one of these operations. I'm leaning towards a bad pump, but it seems strange to me that he had no symptoms the last time he used it and suddenly has nothing. I'm wondering if there's anything else I should check.

 

[TheOldHokie]

My landlord has an L345DT with FEL and mower on the 3-point hitch that he mostly uses a few times a year to mow the weeds on his (our) property. He last used it about 6 weeks ago and it worked fine, today he fired it up and the hydraulics wouldn't work, neither the FEL or the 3-point. There's just no movement whatsoever. I've looked at it, read through some similar problems here and tried a few things, no luck. So here's what I've done: Checked the power steering, which works fine so the pumps are apparently both turning, checked hydraulic fluid level, added maybe 1/2 qt. Tapped on the pressure relief valve, opened the valve up and checked for a stuck plunger, all seems okay there. Opened the filter housing, removed, checked and cleaned the filter screen (it wasn't plugged). Checked the short hose on the supply tube just before the filter, replaced one bad clamp. Removed the inlet fitting from the filter to the top of the pump and filled the pump with oil, it only took a few ounces. Did this twice. I've also cracked a couple lines and gotten no fluid out of them, other than residual dribble. Still nothing after every one of these operations. I'm leaning towards a bad pump, but it seems strange to me that he had no symptoms the last time he used it and suddenly has nothing. I'm wondering if there's anything else I should check.

Start with something definitive. Remove the inlet hose from the loader valve and connect a 3000 PSI pressure gauge to the hose. Start the tractor and read the pressure.

EDIT: Better post a picture of where the loader connects to the tractor Hydraulic system before doing that. I was assuming a bit to much.

Dan

 

[Russell King]

It sounds like the pump may have sheared the pump drive shaft.

If there is no pressure from the above test, then remove the pump and inspect the engine drive mechanism and the pump shaft for damage.

One other thing that is easy to check is the engine oil level. If it is high, the hydraulic pump shaft seal has failed. That failure might be so severe that it cannot hold pressure but that is a very small possibility. AND I am assuming that the FEL is powered by the engine pump not by a separate pump on the rear PTO or on the front of the engine.

 

[007kubotaguy]

Your tractor has a dual pump. The front pump runs the loader and the three-point hitch. The rear pump is the power steering. As you have verified the power steering is working so the pumps are clearly turning. You are correct it would be very unusual for a pump to quit working completely after the tractor sits for a short period of time. They do tend to lose prime when sitting for long periods of time if the pump is Worn-out. But by priming it as you did I would say that is not the problem. I would loosen the outlet tube on the bottom of the pump and crank the engine and see if you get any oil out of the pump. I would assume you have a block on the left hand side under the seat where the two hoses for the front loader attach. You could loosen the front hose and crank the engine without starting and see if you have oil flowing out there as well.

 

[RoverDog]

So after reading the above responses, I've checked the engine oil level and verified that it's normal, so I don't think the hydraulic pump is pumping directly into the crankcase through a bad seal. I disconnected the outlet tube on the bottom of the pump, with the engine off only a little fluid oozed out. We cranked the engine without starting and there was no difference in fluid output. Just for the fun of it, I also disconnected the inlet tube from the top of the pump and looked down into the gears (at least, what I could see through the inlet) and verified that the gears turned when cranking the engine. (Since the power steering still works I didn't expect anything less.) No point in trying to test the pressure with a gauge, there simply isn't any. So what's the best way to prime the pump? It seems like pouring a few ounces into the top isn't going to do it, and of course the filter housing is empty of fluid since I drained it when I checked the filter, so I guess I need to come up with a creative way to refill it. I'm still leaning towards a bad pump, but I just don't see how it could have failed completely just sitting for 6 weeks when it was working fine before. Or maybe it was weak and on its last legs, but he told me that the hydraulics seemed to be working normally and weren't slow/sluggish.

 

[TheOldHokie]

So after reading the above responses, I've checked the engine oil level and verified that it's normal, so I don't think the hydraulic pump is pumping directly into the crankcase through a bad seal. I disconnected the outlet tube on the bottom of the pump, with the engine off only a little fluid oozed out. We cranked the engine without starting and there was not difference in fluid output. Just for the fun of it, I also disconnected the inlet tube from the top of the pump and looked down into the gears (at least, what I could see through the inlet) and verified that the gears turned when cranking the engine. Since the power steering still works I didn't expect anything less.) No point in trying to test the pressure with a gauge, there simply isn't any. So what's the best way to prime the pump? It seems like pouring a few ounces into the top isn't going to do it, and of course the filter housing is empty of fluid since I drained it when I checked the filter, so I guess I need to come up with a creative way to refill it. I'm still leaning towards a bad pump, but I just don't see how it could have failed completely just sitting for 6 weeks when it was working fine before. Or maybe it was weak and on its last legs, but he told me that the hydraulics seemed to be working normally and weren't slow/sluggish.

A few ounces in the top is more than enough to prime the pump.

Before starting the tractor disconnect the inlet hose from the loader valve and stick it in a bucket. If it is pumping you will know real fast after the tractor is started.

Dan