M7060 - Sudden & complete loss of loader/3pt/remote hydraulics, but PS and Transmission still function?

[jjb01016]

Hey all, I'm competent in auto/motorcycles but relatively new to tractors and the associated hydraulics, so I'm hoping ya'll can help me start troubleshooting the basics. Here's my issue and the context:

• I have an M7060 with cab, 600ish hours, 12spd hydrostatic trans, 3 sets of rear remotes and a single 3rd function remote on the loader (all factory Kubota parts).
• I have lost all hydraulic pressure to the loader, 3 point hitch, and my remotes front and rear. Loader and 3 point will bleed pressure and droop due to gravity but not lift.
• No "noise" or whine or anything can be heard from the pump/hydraulic system when I do actuate any of the hydraulics
• If I hook up a 0-5000PSI pressure gauge to any unused rear remote, it does not register any pressure when I move the associated lever in the cab. The linkage is moving properly and triggering the detent on the valve body. Same goes for the 3rd function - no pressure reading when actuated.
• There is no fluid leaking from anywhere on the tractor, no obvious pinched hose, etc.
• I only quickly bumped the transmission forward and reverse, but did verify they were working. Same for the power steering - if I move the wheels back and forth, the PS is working. But I only tested very briefly since my loader is stuck down on my asphalt driveway.

When this loss of hydraulics happened, I had a offset ditch flail mower hooked up to the 3pt hitch, and two of the three rear remotes for the two tilt functions on the flail. Everything was working fine, I drove the tractor with flail to a different area after attaching it, dropped the 3pt, fueled up, then lifted the flail back up. Went to verify the offset functions on the flail were working properly before starting mowing, and the flail extended most of the way out as expected and then suddenly the hydraulics stopped working at that point. No hose was pinched or anything like that - they just suddenly went unresponsive.

Other context in case it matters:

• Added the 3 rear and single front remote around 40 hours ago, and changed the hydraulic fluid and filters at that same time. Have operated the 3pt and loader throughout that time without issue, same for the transmission/power steering since the service.
• I bought the offset flail mower after installing the front and rear remotes. After purchase I quickly hooked it up to verify the unit functioned, and to briefly test it out. Everything worked fine - both mower and my new remotes - but, I foolishly caught one of the hard line hoses of the flail on a branch while playing around with it and the hard line broke, which dumped a fair bit of hydraulic fluid out for a few seconds until I noticed - probably less than ten seconds total time. I repair the hard line, learned my lesson and moved on. No damage was done to the tractor remotes. This was at least 30 hours of tractor use ago, and again all other hydraulics - loader, 3pt, ps and trans - have been operating normally since this bonehead move of mine. But it's worth including in case that could factor in.

Any suggestions on where I should start? How can I tell if my pump is functioning? Even though they're brand new, should I replace the two hydraulic fluid filters for the heck of it? Why are my PS and trans operating - I thought they ran off the same pump as the remotes, 3pt and loader???? Or is there just residual fluid in those systems? Does the system self bleed and if so, how come it hasn't resolved itself? And wouldn't I hear groaning??? Are there safety valves or similar that might be triggered do to a clog or internal issue?

Help is appreciated! I will run down any suggestions as fast as possible. I need this thing back up and running!

 

[jjb01016]

This is how I checked for any sign of pressure at my remotes FYI...I assume hooking up a guage like this to the Ag fitting and cycling the remote would tell me if I did have any pressure, correct? In other words, I don't have to use a tee with a loop back to the other side of the remote right?

 

[TheOldHokie]

This is how I checked for any sign of pressure at my remotes FYI...I assume hooking up a guage like this to the Ag fitting and cycling the remote would tell me if I did have any pressure, correct? In other words, I don't have to use a tee with a loop back to the other side of the remote right?

View attachment 176204

That tells you what pressure you are getting at the work port on the valve when the lever is operated. That SHOULD be the same as the pressure at the inlet port on the valve which should be the same as the pressure comingvfrom the pump. Notice my emphasis on SHOULD.

So where is the loss of pressure happening? Since the loader does not work I would suggest moving the gauge to the inlet pipe/hose on the loader valve. That will get you a more direct measure of pressure at the pump and eliminate the other components. Let me look at the parts diagrams to see how to safely rig for that test.

Exactly what model is your M7060 and loader?

Dan

 

[jjb01016]

M7060HDC12 SN 51948
LA1154 Loader

Thank you!

 

[TheOldHokie]

M7060HDC12 SN 51948
LA1154 Loader

Thank you!

OK - as I feared it appears the loader control valve provides the primary pressure relief for the pump so directly testing pump pressure is not a simple rig.

You could safely connect the gauge to the PB port on the loader valve but given the loader isnt working I suspect thats going to show the same pressure as the rear remote.

My spidey sense is telling me the relief valve in the loader control valve has probably failed open but the only way to know "for sure" is to test at both inlet and outlet. There are multiple optjons for that control valve. Do you have the standard or self leveling valve?

Dan

 

[jjb01016]

Dan - standard valve. How easy is it to just replace the loader control valve, and any chance you can point me to the appropriate exploded parts diagram and a part number? I'd like to start familiarizing myself with the components...

 

[TheOldHokie]

Dan - standard valve. How easy is it to just replace the loader control valve, and any chance you can point me to the appropriate exploded parts diagram and a part number? I'd like to start familiarizing myself with the components...

You would not replace the control valve - just the relief vakve. I am having difficulty figuring out which of multiple valves is used on your tractor. This one seems likely. Personally I would want to verify thats the correct valve and that its the problem beford buying a $250 part - item #20 in this diagram.

https://messicks.com/catalogs/kubota/la1154a/control-valve/b00502-control-valve-component-parts-m7995-m7996-standard-valve

 

[jjb01016]

Ok - figured out where the loader control valve is, looks like it is model M7996 as you guessed. Yeah, $250 isn't exactly cheap. So can you go over it again, is there something I can do to check the state of the relief valve?

Also, I read up and think the answer is no, but are there any global hydraulic lockouts or similar that might cause this issue?

And what about the PS and trans working - does that tell me anything? Or is it the case that those two systems are probably both still full of fluid but given a small amount of operation, will also fun out of fluid and stop working? I'm curious about this. Would a working hydraulic pump but failed open relief valve result in working PS and trans, but nonfunctional hydraulics since I'd have FLOW, but not pressure?

 

[jjb01016]

Also, the parts diagram makes it look like the relief valve (#160) is on the loader control valve, but the WSM seems to show it back by the remotes? Is that correct? When i look at my loader control valve I don't see anything at the location shown in the parts diagram that would correspond with the relief valve...did Kubota just "drop" that relief valve exploded diagram here for convenience?

 

[TheOldHokie]

The PS and transmission are independent of the implement hydraulics. They have their own pumps and circuitry. Nothing is going to run out of fluid in any of the circuits.

If the loader relief valve is wide open to tank the vast najority of implement pump output is going to take that path because it is the path of least resistance.

If its as easy to get to the loader valve as that pictire makes it look all you need for a direct pump pressure test is your gauge, a flow conntrol valve, a few fittings, and some low pressure tubing. Thats pribably $75 max but I would spend it just to verify the proplem is in the loader valve. Plus itsca valuable addition to your tool chest.

Dan

 

[TheOldHokie]

Also, the parts diagram makes it look like the relief valve (#160) is on the loader control valve, but the WSM seems to show it back by the remotes? Is that correct? When i look at my loader control valve I don't see anything at the location shown in the parts diagram that would correspond with the relief valve...did Kubota just "drop" that relief valve exploded diagram here for convenience?

View attachment 176213 View attachment 176214

Different reliefs. The optional loader is added ahead of the standard tractor relief so it becomes the one in control. If its busted andvrelievungcat zerk pressure there is nothing the ine in thev3pt can do to change that.

Dan

 

[Botamon]

I don't have a clue as to the cause of your hydraulic problems. But as the satisfied owner of a 2016 M7060 HDC12 I want to correct your assertion that you have a M7060 with a "12 speed hydrostatic transmission". M7060 never had a hydrostatic transmission. It is a "shuttle shift".

 

[jjb01016]

Ha, shows what I know about these tractors! If you stopped me and asked me what gear I was in, I'd have to say "Bunny 3" or "Turle 1" like I was a toddler

 

[jjb01016]

I chatted with a tech at the local dealer today, he was pretty helpful but we sort of ended up at a dead end. I did gather from the conversation and follow-ups just now studying the hydraulic circuit diagrams that whatever shaft runs the hydraulic pump for the power steering, also runs the hydraulic pump for the 3pt hitch/loader/remotes. And if I have power steering, then at least that pump shaft isn't broken.

The tech didn't recall any relief valve failures on this model loader, but said it could be worth a shot pulling it and checking if anything was stuck/broken. He mentioned counting exact # of turns of the jamb nut on the valve so that I had an accurate starting point when reinstalling, if I chose to do so.

He looked through tech bulletins and mentioned one where incorrect adjustment of remotes caused premature wear on the hydraulic pump, but didn't think that was relevant here either.

 

[#40Fan]

If you think the relief valve might be the issue, before taking it apart, how about smacking it with something soft, yet heavy? Try this with the engine off, then running if off didn't help.

 

[jjb01016]

Hey - it's never a true boondoggle unless you start resorting to banging things with a hammer!!

Yeah, it probably makes sense to at least give it a quick try.

I found some posts just now talking about shock loads to the hydraulic system resulting in failed relief valves and complete loss of hydraulic function. While I don't think that's what happened here, at least there's precedence that it can happen.

 

[TheOldHokie]

I chatted with a tech at the local dealer today, he was pretty helpful but we sort of ended up at a dead end. I did gather from the conversation and follow-ups just now studying the hydraulic circuit diagrams that whatever shaft runs the hydraulic pump for the power steering, also runs the hydraulic pump for the 3pt hitch/loader/remotes. And if I have power steering, then at least that pump shaft isn't broken.

The tech didn't recall any relief valve failures on this model loader, but said it could be worth a shot pulling it and checking if anything was stuck/broken. He mentioned counting exact # of turns of the jamb nut on the valve so that I had an accurate starting point when reinstalling, if I chose to do so.

He looked through tech bulletins and mentioned one where incorrect adjustment of remotes caused premature wear on the hydraulic pump, but didn't think that was relevant here either.

I think your tech is in over his head.

The loader valve is ahead of the tractor relief and MUST have its own inlet relief. That valve is clearly spelled out in the parts diagram. If the loader did not have a relief normal operation oc the loadef would deadhead the pump and destroy it in very short order.

Incorrect adjustment of the 3pt valve not the remotes is probably what the tech is thinking about. Thats a commin probkem that can cause loader priblems but its not your current problem.

You can pull the relief valve and take it apart if youbwant but I would just test pump inlet and outlet pressure and be done with it. Simple and definitive result as opposed tk you trying to evaluate the innards of the valve. As you yourself have acknowledged you have minimal knowledge about how this stuff works.

Dan

 

[Russell King]

If its as easy to get to the loader valve as that picture makes it look all you need for a direct pump pressure test is your gauge, a flow control valve, a few fittings, and some low pressure tubing. Thats pribably $75 max but I would spend it just to verify the proplem is in the loader valve. Plus itsca valuable addition to your tool chest.

Dan

@TheOldHokie
I assume this equipment (flow control valve, fittings,…) are described in the WSM but probably use Kubota part numbers or tool numbers. I also assume the test procedure for the pump pressure is in the WSM.

But I think it would be very helpful to @jjb01016 if you could provide some guidance or links to what equipment you think he needs. I would try to describe it but don’t want to get into the middle of this and make it more confusing. If you want me to take a shot at it, just say so!

I am assuming you want him to test the pump pressure by removing the line to the power in port, attach the end of that line to a tee with the gauge in the tee, then the flow control needle valve also on the tee, then the output of that needle valve routed to the transmission fill port (or a bucket).

 

[TheOldHokie]

@TheOldHokie
I assume this equipment (flow control valve, fittings,…) are described in the WSM but probably use Kubota part numbers or tool numbers. I also assume the test procedure for the pump pressure is in the WSM.

But I think it would be very helpful to @jjb01016 if you could provide some guidance or links to what equipment you think he needs. I would try to describe it but don’t want to get into the middle of this and make it more confusing. If you want me to take a shot at it, just say so!

I am assuming you want him to test the pump pressure by removing the line to the power in port, attach the end of that line to a tee with the gauge in the tee, then the flow control needle valve also on the tee, then the output of that needle valve routed to the transmission fill port (or a bucket).

The WSM describes the use of a high dollar commercial flow/pressure tester like this one that sells for $900.



You can obtain the same results with my "poor man's flow/pressure tester" (pictured below). You use it to test pump discharge pressure just as you described. For flow rate @ pressure you pair it with a "stop watch" and a clean 5 gallon bucket. Total cost to build about $75 and he already has the gauge. I will share the procedure and sources for parts if he wants to go that route.

Dan

 

[Tx Jim]

I'll add to the excellent information that TheOldHokie has posted that one should perform good diagnostic procedures as you're attempting to do before considering replacing any major parts?

Over my many yrs associated with repairing hyd problems I've read of hyd pumps & valves being replaced to only determine the replaced parts were actually good & not the hyd problem.

I think the check valve would require some serious inspection . It cost $416.47 so any replacement would require some more diagnostic procedures being performed. I think for a test that check valve could be temporarily removed & orifices capped off