Backhoe Side to Side -- Stuck?

[TWD]

Thanks rScotty!

Funny you mention the pushing it back, that's what I did once on a stump already, just hooked it and drove around to straigthen it out...

I don't mind it being random\weird but when I'm going 10mph down a 1 lane road with 200 homes and it randomly slams to the other traffic laneside that's not safe or good. I also ironically sometimes put a log in the backhoe on the left side and drive home along the road, it could be catastrophic in such instances if it auto-swings to the opposite side with a 10' 20" tree in the grips!! Yikes!

I'm going to check a bunch of stuff.

@rScotty no one swapped that m62 valve yet or what? Seems like if it's resolved that may be a way.

I did discover a leaky hose in my valves for the backhoe which explains why it's bleeding-off and my hoe is getting floppy and jerky feeling... excited to snug that up

 

[rScotty]

Reading through your explanation again, what is happening with yours does sound different from the usual, "power in one swing direction but not in the other".

For one thing, I've not ever heard of anyone else whose hoe suddenly began swinging under power all by itself. That sure is scary. Are you positive?
Of course there is a swing lock. I think if I were you I'd be using it when traveling.

I sometimes use that way of carrying a tree trunk myself. Carrying a 30 foot slender pine tree it makes me feel like Don Quixite getting set up to go tilting at trashcans....very tempting....
rScotty

 

[rScotty]

BTW, I just looked up the complete M62 replacement control valve assembly: $4K & change.

 

[TWD]

Reading through your explanation again, what is happening with yours does sound different from the usual, "power in one swing direction but not in the other".

For one thing, I've not ever heard of anyone else whose hoe suddenly began swinging under power all by itself. That sure is scary. Are you positive?
Of course there is a swing lock. I think if I were you I'd be using it when traveling.

I sometimes use that way of carrying a tree trunk myself. Carrying a 30 foot slender pine tree it makes me feel like Don Quixite getting set up to go tilting at trashcans....very tempting....
rScotty

I went out and tried on my m59, and it acts like everyone elses... I can push it back by hand or my wife pulling on it to re-center\go left, works fine! Did that a few times and now I have power (10%) to move it left, but it won't go more than a little past center to the left now, ha! I'm guessing it's the control valve. Sadly, yeah it did randomly move on me RIGHT as I hit the main road once already...

Good call on the lockout left\right, totally forgot that one existed!


Woah! $4k+, I though the M59\Stock one just under $2k was bad when I glanced.

 

[oldnslo]

Wouldn't me physically moving the lever\valve into another position test this, .

If you are moving the spool it should change what cylinder is doing.

Next step is gauges in both cylinder ports on the swing spool. Even better if you have one is a bi-directional flow meter in the line going to swing cylinder that is not swinging back. Now you can check for both pressure and flow.


Problem is flow meters are expensive and take up some space so you usually need another hose to get them into a circuit.

Other option is needle valve or flow control plus gauge between valve and flow control. You can now close the flow control and you should get system pressure. On assumption the swing reliefs are in the directional valves that would test the swing relief.

Bottom line you somehow have to isolate components to narrow down which one is failing.

What type of swing cylinder is on an M59? Two opposing single acting, two opposing double acting, vane type swing cylinder?

 

[m59owner]

You will never guess what happenned..... I joined the forum tonight because yesterday digging out a stump on a slight incline where my M59 tractor was leaning to the right. After a few movements of the backhoe it stopped responding to the left swing control input and slowly moved all the way to the right. I moved the tractor back to even ground and with the help of another person, swung it back to center and used the transport safety pin to secure it in place.

Mine is a 2014 model with just under 1,700 hours. Like others, no leaks or bad hoses. Linkage and connections all work smoothly and move as they should. Initial thought it was a control valve issue but reading some of the posts I saw it appears it is a mystery that can solve itself with some shaking and wiggling.

When I looked at the control valve diagram there is a pc in there called a poppet (#80 below). I am not sure what that is. Is that the pressure relief valve and could that get stuck in a position that lets the fluid pass one direction but not the other? If so, could that be removed, cleaned and inspected? I will try the shake and wiggle thing in the morning but was hoping for something more scientific to check. Thanks!

Found this handy flow chart below someone else posted on an old thread where you can see how the flow works for left and right swing cylinders. I think you would say they work in parallel. I suppose a cylinder seal could be an issue but seems unlikely.

 

[oldnslo]

My guess is that item 80 is the load check and not a relief valve.

I don’t see any work port reliefs in that parts break down

That hydraulic diagram shows two double acting cylinders, one extending while other is retracting so push and pull circuit.

 

[m59owner]

I found the parts diagram for the swing control valve below and it shows an overload relief valve on the top and bottom (part # 100). One for right swing and one for left swing. I had an issue 2 years ago where the boom would fall and pulling back on the stick (boom up) would raise it and letting go of the stick it would fall to the ground. I ended up swapping the lower and upper overload valves and I was able to keep working since the boom could not fall up.... I ordered a new one but have not put it in as I have not had any further boom issues.

I just checked the overload relief valve for the swing control valve, and it is different part number that the spare I have. I might try swapping the upper and lower relief valves to inspect and see what happens. I saw on another post (link HELP! My Backhoe won't swing left!) that someone had the same boom issue (falling down) and found part of the O-ring on the inside the relief valve was damaged. Kubota told them it was not serviceable, but they found a suitable Oring and said it works find now. I am getting the sense that the pilot style relief valves can be quirky. Some think it is air getting in the pilot causing it to stop working. Could my working on the side of a hill and the machine jostling around pulling on roots allowed some air in the system and shaking and wiggling the machine while tilted to the left with get the air out. Or maybe there is some contamination in the relief valve and cleaning it will do the trick. Will see.

My take from the other post I found. In the example below, if the overload relief valve on the left is stuck open for some reason, instead of fluid at pressure going out port B6, it is flowing back through the overload relief valve back to the hydraulic tank. With no fluid under pressure going out port B6, there is nothing flowing back in through port A6 as that there is no fluid being pushed out the other end of the swing cylinders. When you let go of the boom left/right stick, the load check valve (#4) should close and lock the boom in position. But with the overload relief valve stuck open, the hydraulic fluid just passed back to tank while gravity moves the boom and pushed the fluid back out through the open relief valve.

Hard to think a bubble air or a small bit of an O-ring could divert 2,700 psi of pressure even when there is no overload condition. Feels like that is where the issue is.

 

[oldnslo]

Air bubble would not cause a relief to fail but a piece of contaminate certainly will especially if that is the style of relief that also has anti-cavitation check built in. The check opens at real low crack pressure to draw oil from tank line to help keep an over running cylinder full of oil. Then if check sticks open it prevents the relief from building pressure.

 

[TWD]

If you take the valve out to check for broken gasket\o-ring please take pics as you go and share

It appears it's not too much effort, and that's my plan to tackle in the coming weekend.

Also, did you check your hydrualic fluid level? I did, mine was at the bottom line I'm going to top it off and maybe get lucky it was air in the line... probably not, but hey, worth it