Lost all hydraulic function except Hydro

bugstruck · Aug 1, 2009

Been awhile but I know where to go when I'm stumped. Lost all hydraulic function to FEL, power steering, and BH on my Kubota L3130. Hydro is working fine to move the tractor around. Pulled tractor out of the gargage (everything hydraulic was working fine), left it running and jumped off for a moment, heard an odd humming that stopped in several seconds. Went back and nothing is working. Jockeyed the control valves to see if anything was hanging and all feel normal. Cylinders will drop the implements as if the tractor is off when I jockey the control valves. I called the dealer service tech who was on the way out the door for some well deserved rest from the grind. He said it could be as simple as a relief valve or as bad as a pump. No visible line or other leaks. Anybody have an idea if this is relief valve related where to start and what to try?

Any help or ideas would be appreciated.

J_J · Aug 1, 2009

Install a pressure gage in a tee somewhere after the pump, and before the control valve.
Turn the steering wheel, or activate the FEL , or BH. With nothing activated, if the pump is good, you will have very low hyd flow. Once you activate the FEL, You cause the pressure to build, and as you hold it to the stop, a relief valve should come on, and the pressure gage should read relief pressure. If no pressure at all, You might pull the pump and look at the pump shaft.

With hydro-stat running, that means that at least you have fluid, but check the level anyway.

Egon · Aug 1, 2009

Does your tractor have separate pumps for the HST and the hydraulics?

If so maybe check on the pump connection drive line system.

kennyd · Aug 1, 2009

Egon said:
Does your tractor have separate pumps for the HST and the hydraulics?

If so maybe check on the pump connection drive line system.

All tractors do. The Hydrostatic tranny is driven from the crankshaft while the auxiliary hydraulic pump is either driven from a belt or directly coupled to the engine and gear driven

I called the dealer service tech who was on the way out the door for some well deserved rest from the grind. He said it could be as simple as a relief valve or as bad as a pump.

If it was the PRV, the most likely you would hear a squealing noise...I'm betting on the pump or the gear that drive's it-Sorry. Is your machine under warranty?

bugstruck · Aug 2, 2009

Kenny,

I think you may be right, I'm suspicious of the pump too. I did check the manual and it's gear driven off the enginge as you mentioned. I did locate it after a few minutes. No, it's not under warranty as I bought it in Dec. 04, so I"m guessing that could a very expensive repair.

I'm having the dealer come get it Monday or Tuesday and will advise the outcome. This is a little more than I want to tear into and there is always a chance I'm missing something anyhow. I must admit that the hydraulic plumbing on these CUT's is a little daunting to someone who doesn't work around it. Tracing the various lines around the tractor, more than I ever had prior reason to do, made me aware of that.

Thanks for the reminder in the Kubota forum on double posting. I should have remembered that. Figures another Westminster guy got me straight. Can that other thread be removed?

Thanks guys

kennyd · Aug 2, 2009

bugstruck said:
Kenny,

I think you may be right, I'm suspicious of the pump too. I did check the manual and it's gear driven off the enginge as you mentioned. I did locate it after a few minutes. No, it's not under warranty as I bought it in Dec. 04, so I"m guessing that could a very expensive repair.

I'm having the dealer come get it Monday or Tuesday and will advise the outcome. This is a little more than I want to tear into and there is always a chance I'm missing something anyhow. I must admit that the hydraulic plumbing on these CUT's is a little daunting to someone who doesn't work around it. Tracing the various lines around the tractor, more than I ever had prior reason to do, made me aware of that.

Thanks for the reminder in the Kubota forum on double posting. I should have remembered that. Figures another Westminster guy got me straight. Can that other thread be removed?

Thanks guys

Your in Westminster also? The other thread can only be deleted by a moderator...

You may get luck-possibly just a gear chewed up or even better just a key on the shaft sheared.

Just by chance, the backhoe did not come unplugged throwing the system into relief?

bugstruck · Sep 5, 2009

Kenny,

Sorry being so late getting back. Had an unexpected detour through the Carroll Hospital Center but all is good on that end thankfully. Yes I'm in Westminster.

Your guess was very close on the problem. The bearing failed,wiped the gear, and actually snapped the pump shaft too. If your going to break it do it right

. The bad news is it was a fairly expensive repair at almost $1,500.00 but that problem shouldn't recur and the dealer treated me decent. No haul in or out costs. Seems Kubota had a service bulletin come out right when I bought my tractor in 04 so I'm sure others had the same problem. Here is how Kubota explains the problem:
"When operating the above units with the front end lower than the rear for extended periods of time it may cause the engine oil to back away from the hydraulic pump gear, causing lack of lubrication. As a result bearing failure may occur. They give this example: Operating the BH90 backhoe with stabilizers fully extended and the front wheel contacting the ground"

Well I certainly did what is described in their example and with the front end down a pretty hard slope to boot.

Kubota has a fix known as a "Holder Kit". What they do is swap the oil filter holder with one that has a connection for a line to the gear housing on the hydralic pump. So they pressure feed that gear with the kit. I need to take a closer look as I'm not sure exactly where it feeds in but I suspect the pump holder assembly which is between the engine block and pump.

I presume Kubota fixed this or put the holder kit on newer models? If anyone has a desire I can post the serial numbers the bulletin applies to. The issue was with L3130, 3430, and 3830 models. If you don't operate nose down for extended periods it's not an issue. The kit is part number TD030-99300 and it comes with an instruction manual. I'm a half fair back yard mechanic and I'd have tackled the swap a few years back but not nowdays. Those guys have to eat too.

kennyd · Sep 5, 2009

Thanks for getting back to us Chris, it's always nice to hear how a situation ends...even if it is very costly. Glad your in good health also...

RobertsMassie2310 · Nov 1, 2009

am having the same problem with my massie GC2310...noted a scaped hose but i guess just a slow loss of hydraulic fluid, but one day couldnt get the bucket or backhoe to lift...in fact no control on stabilizing outriggers either. I do have drive capabilities but since everything is on the ground its hard to get anywhere...replaced the hose and thought i had bled the system well after refilling it but still no movement from any of the attachments...can anyone help?