L4740 HST - all hydraulics suddenly stopped working

[BayouB2601]

Have any of you guys had your Hydraulic pump go out suddenly. I ask because the tractor hydraulics have been working just fine as far as I can tell But today they just stopped. Problem started with the loader valve start sticking. Also, startEd using the 3rd function valve (grapple) this weekend for the first time while bush hogging. worked fine until everything stopped. No loader, no transmission, no pto, no steering. The tractor has almost 900 hrs on it. I bought it about a year ago w/ 850 hrs. I changed All the filters and fluids right after I bought And the tractor has the right amount of fluid. I was thinking it might be that the safety valve is possibly stuck open or it’s just time for a new pump. I thought the pump would last longer than 900 hrs or it would at least start acting funny as it was going out. Any help or suggestions would be greatly appreciate.

 

[PoTreeBoy]

Have any of you guys had your Hydraulic pump go out suddenly. I ask because the tractor hydraulics have been working just fine as far as I can tell But today they just stopped. Problem started with the loader valve start sticking. Also, startEd using the 3rd function valve (grapple) this weekend for the first time while bush hogging. worked fine until everything stopped. No loader, no transmission, no pto, no steering. The tractor has almost 900 hrs on it. I bought it about a year ago w/ 850 hrs. I changed All the filters and fluids right after I bought And the tractor has the right amount of fluid. I was thinking it might be that the safety valve is possibly stuck open or it’s just time for a new pump. I thought the pump would last longer than 900 hrs or it would at least start acting funny as it was going out. Any help or suggestions would be greatly appreciate.

You've checked the fluid level since this started?

I'd crawl under it and see if a filter or suction line has been displaced or damaged. Do you see any oil seepage? Also check the oil cooler lines and clamps.

 

[Nicksacco]

I agree with @PoTreeBoy .
Also, check hard suction lines for rubber hose couplers that are leaking.
Check each suction connection on each pump.
A small crack in a hard line or fitting or leaky coupler will cause this.
It is not necessarily the pump that goes bad in all cases.

 

[TheOldHokie]

Have any of you guys had your Hydraulic pump go out suddenly. I ask because the tractor hydraulics have been working just fine as far as I can tell But today they just stopped. Problem started with the loader valve start sticking. Also, startEd using the 3rd function valve (grapple) this weekend for the first time while bush hogging. worked fine until everything stopped. No loader, no transmission, no pto, no steering. The tractor has almost 900 hrs on it. I bought it about a year ago w/ 850 hrs. I changed All the filters and fluids right after I bought And the tractor has the right amount of fluid. I was thinking it might be that the safety valve is possibly stuck open or it’s just time for a new pump. I thought the pump would last longer than 900 hrs or it would at least start acting funny as it was going out. Any help or suggestions would be greatly appreciate.

Pumps dont usually fail that way but its not impossuble. Personally I suspect something else is going on. In any event start by checking pressure/output at the pump.

Dan

 

[BayouB2601]

Thanks for the responses. I checked those things and found no leaks and the tractor was full of fluid. I changed the filters (original gray filters w/ 870 hrs on the machine… fyi - I bought it used and did not notice the original filters were still on it… dope!) to rule out clogged filters and nothing changed. I got the pump off last weekend and it was shot. The shaft coming out of the pump was sheared off in the drive gear on the tractor side (inside the pump holder part). I took the pump apart and inside I found one of the drive gears had sheared off causing both drive gears to gouge into the pump housing. There were large metal shaving’s everywhere inside. Ordered a new pump ($$$$) and drive gear, o rings, pump holder (as kubota calls it) and bearing. Yesterday evening I got the new pump installed. Fired up the tractor, let it idle, and hydraulics were all back.

New problem, strange sound coming from the engine that was not there before. The engine was purring like a kitten when I left it after the pump failed. I started looking around and I see an oil fill cap on the side of the engine near the hydraulic pump. I change the engine oil right after I purchased it (15 hrs ago - should have done the same w/ hydro fluid). I filled it using the top oil fill cap.

Question - what is this cap on the side for near the pump and should I put something in there? I see what looks like engine oil inside and the engine dip stick is right below it. Can someone fill me in on what this is for and if I should check a fluid level there? I’m at a loss.

 

[TheOldHokie]

Thanks for the responses. I checked those things and found no leaks and the tractor was full of fluid. I changed the filters (original gray filters w/ 870 hrs on the machine… fyi - I bought it used and did not notice the original filters were still on it… dope!) to rule out clogged filters and nothing changed. I got the pump off last weekend and it was shot. The shaft coming out of the pump was sheared off in the drive gear on the tractor side (inside the pump holder part). I took the pump apart and inside I found one of the drive gears had sheared off causing both drive gears to gouge into the pump housing. There were large metal shaving’s everywhere inside. Ordered a new pump ($$$$) and drive gear, o rings, pump holder (as kubota calls it) and bearing. Yesterday evening I got the new pump installed. Fired up the tractor, let it idle, and hydraulics were all back.

New problem, strange sound coming from the engine that was not there before. The engine was purring like a kitten when I left it after the pump failed. I started looking around and I see an oil fill cap on the side of the engine near the hydraulic pump. I change the engine oil right after I purchased it (15 hrs ago - should have done the same w/ hydro fluid). I filled it using the top oil fill cap.

Question - what is this cap on the side for near the pump and should I put something in there? I see what looks like engine oil inside and the engine dip stick is right below it. Can someone fill me in on what this is for and if I should check a fluid level there? I’m at a loss.

Pump took a crap and left the system full of debris. You replaced it and hopefully cleaned out the debris.

Everything works now but you have a strange sound. I think I would focus on locating and identifying the source of that sound.

Dan

 

[Russell King]

Some engines are used in different applications and have multiple fill points. What you are looking at is (probably) a second fill point for the engine oil.

Look at the illustrated parts list here

Kubota Tractor Corporation - Illustrated Parts List

- K-PAD - Parts Lists - Illustrated Parts Lists - diagrams

apps.kubotausa.com