Backhoe Side to Side -- Stuck?

[Smokeydog]

Also have intermediary loss of power swing left and boom down on my 2013 M59. Suspect a spec of debris. Have not taken the time to disassemble to check as the problem is transitory. Interested to any solution.

Definitely use your swing lock for road transport.

 

[rScotty]

Hello to all the M59 guys out there....

I'm the guy who originally posted those illustrations in messages 16 & 18. Yes, I agree with OldnSlow that the most likely culprit is some crud, bubble, or malfunction in the RELIEF VALVE for the swing circuit (shown below). Not in the Load Check valve.

The M59 control valve assembly uses a number of these identical RELIEF VALVES in all the power circuits. And yes, that multiple use relief is one of the main hydraulic features that was completely re-designed in the different control valve for the M62.

Originally I was so sure that valve was responsible for the swing problems that I ordered a couple of those relief valves just to have them on hand. They are used in pairs, and cost half back then what they do today. But I never used them, because while waiting for them to arrive, I figured out that I might be able to purge the relief valve using gravity to swing the boom...
That was a ong shot and only theoretically possible, but even a blind pig finds an acorn now and again. And to my amazement it worked! It has worked twice now for me and countless times for others. I've explained it before, maybe others can explain their version of how to do it and we can combine forces.

If it hadn't worked, my next move would have been to simply remove those RELIEF VALVES, disassemble, clean, and replace. They look serviceable, though since I never did I don't know for sure.

rScotty

 

[loggin]

Very interesting information here!! Trying to understand a little more. rScotty, is that diagram for the BT1200? Looks similar to the spool valve for the BH92 that I have. I have not encountered this swing issue as of yet but am interested in finding out more. Seems there have been some BH77 swing issues but can't find any good explanations for fixes so far. Please keep the ideas coming!!

 

[rScotty]

Good question about the other backhoe models. I don't know if they have a similar control valve setup or not. Real interesting question you bring up about that BH77 and other add-on Kubota backhoe models though..... I don't know the answer and never thought about it. I can't remember any problems being reported here on TBN with the other add-on implement hoes - or even with the factory hoes on other TLBs for that matter. I may have just missed them.

That diagram you asked about in message #22 is one I pulled directly from Messicks' parts catalogue online so we could also see the updated price for the relief valve. Messicks has it listed under BT1200 parts for the M59 and my guess is that they got that right.
Why do you ask? Did you see any difference?

The other earlier diagrams in earlier messages came from my M59 shop manual backhoe supplement, so I have more confidence they are for our M59s.

I hope you do take those relief valves apart and give us a report... although I completely understand if you find the same easy fix others have and never get to it.
Maybe Kubota will help us with this. Their redesign of that BH control valve for the M62 makes me think they may be paying attention.

And I am going to be religious about using the swing lock during transport from now on.
That is something I have not always done in the past.

rScotty

 

[m59owner]

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.

Thanks oldnsio. Good to know. Long workdays this week so may not get to my shake and wiggle attempt until the weekend.

 

[m59owner]

I have the spare pressure relief valved for the boom hydraulic control valve when that acted up a couple of years ago and will take that out of the bag for some close up pictures this weekend. I may still remove the swing relief valve to compare even though the 2 are different part numbers. Maybe they are just set to relief pressure at different points. Will keep the group posted.

 

[m59owner]

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

For reference, I had checked the fluid level the day before and all was good with no leaks to draw it down. Will recheck this weekend again but expecting it to still be fine. I hope to take the problem relief valve out to compare to the spare one I have for the boom once I get time. I will take some pics to share.

 

[loggin]

Good question about the other backhoe models. I don't know if they have a similar control valve setup or not. Real interesting question you bring up about that BH77 and other add-on Kubota backhoe models though..... I don't know the answer and never thought about it. I can't remember any problems being reported here on TBN with the other add-on implement hoes - or even with the factory hoes on other TLBs for that matter. I may have just missed them.

That diagram you asked about in message #22 is one I pulled directly from Messicks' parts catalogue online so we could also see the updated price for the relief valve. Messicks has it listed under BT1200 parts for the M59 and my guess is that they got that right.
Why do you ask? Did you see any difference?

The other earlier diagrams in earlier messages came from my M59 shop manual backhoe supplement, so I have more confidence they are for our M59s.

I hope you do take those relief valves apart and give us a report... although I completely understand if you find the same easy fix others have and never get to it.
Maybe Kubota will help us with this. Their redesign of that BH control valve for the M62 makes me think they may be paying attention.

And I am going to be religious about using the swing lock during transport from now on.
That is something I have not always done in the past.

rScotty

The reason I asked was because I was fumbling around on Messicks website to look at the different spool valves of other backhoes and could not find the diagram you posted. Likely my fault and just somehow missed it. Getting old.....

 

[loggin]

For reference, I had checked the fluid level the day before and all was good with no leaks to draw it down. Will recheck this weekend again but expecting it to still be fine. I hope to take the problem relief valve out to compare to the spare one I have for the boom once I get time. I will take some pics to share.

Looking forward to see what you find out!!

 

[rScotty]

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.

OldnSlow, thanks for your insight, it always helps. I agree that item 80 is a typical load check that we find on most control valves - and that it is not involved in the swing problem we are working on.

Yes, the work port relief valves, aren't shown in that parts break down. For some reason the parts book shows the reliefs on the next page, and we see them again in the attachment to post #18 above.

A couple of things are interesting gleaned from the parts & shop manual:
1. identical relief valves are used for extending and retracting each cylinder. These are only used on the backhoe control valve. There are plenty of other different relief valves on other hydralic circuits on the M59.
2. There are two part numbers for the BH relief valves: Dipper and swing use one # (4 total).
The boom, bucket, and thumb use the other. Like M59owner, I suspect that the difference is the relief setting.

The swing cylinders are double acting and also have their own dedicated swing pump which has yet another primary relief valve in the 3pt case. And interestingly it runs at a sligtly lower pressure than the main. But I don't think either is part of this swing problem.

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.

Right on! That style relief valve does indeed have an anti-cavitation feature. It works by comparing the working pressure vs the "return to tank" pressure....which means that the return to tank pressure is NOT ZERO. It is lower than the working pressure but still significant. Several hundred psi is my guess.

I'm stop here, but will say that anti-cavitation as it is designed in this valve means that sump tank fluid level is important...BUT way more important is to avoid any leaks in the BH hoses&connections - that is absolutely critical.
To a lesser degree of importance, I personally would not let the BH components move around much without the engine running. Use the swing and boom locks. Maybe add a chain on the bucket & dipper.
Any of these could cause temporary BH movement problems just because of air in the system.
My best guess is that debris does about the same thing as air in the relief valve, but not so temporary.
rScotty