Backhoe 4672 Backhoe problem

[avorancher]

Yesterday my 4672 backhoe started giving me problems. Sometimes it won't swing to the right. It usually begins working again if I swing it to the extreme left, then back to the right. It only happens intermittently. I also noticed that when I put it back centered then remove the PTO power to move the tractor, the backhoe drifts from side to side like it is disconnected.... it has never done this before.

I don't see any leakage or problems with the swing cylinders themselves. I do have a slight leak on the dipper cylinder and the fluid ran low a couple days ago. I refilled it but didn't notice the problem until yesterday.

 

[Pks]

...sounds like air might be in the system. If that's the case, the air should work itself out of the lines with use.

 

[ozzie tractor]

if its not air (should work itself out in only a few minutes if it is) causing the problem then i would suggest the internal seal on the swing ram has failed. i have seen seals work intermittently as the remnants of the seal float backwards and foward in the groove. sometimes they seal and sometimes they dont. pull the ram out and have a look inside. there are a thousnad different ways to diagnose this without taking the ram off and i am not going to start a thead on that. personally i think its the ram and if it where mine i would pull the ram off and strip it. rams are a fairly simple thing to get apart.

 

[ronjhall]

Have you checked oil level again since you refilled it. Now that you have cycled all the cylinders. It may be low again.

 

[m7040]

Three areas to look at: 1) oil level low 2) swing cylinders leaking ( If single acting you can tell if they leak at the end plate) 3) air in system.

Just rebuilt my 4 inch diameter swing cylinders and it was not that difficult to install new seals. Works very well now where before the side movements were hard to control accurately due to the leak.

 

[avorancher]

"i would pull the ram off and strip it."

Sorry Ozzie tractor, I'm such a novice that you'll have to explain in layman's terms for me.... is a ram one of the swing cylinders? And how would you strip it? (boy...I must be dumb).

None of the cylinders are leaking externally. Oil level is OK now. The problem is a little bit better, but still fails to swing sometimes. I can usually get it to work by just trying 4 or 5 times and it will suddenly take hold.

M7040... my backhoe was used and it has always been very difficult to control side to side (note the gash on the side of the house). I'm leaning towards replacing the seals. I'll check with local dealer to see if there is a "kit" or something.

Thanks all.

 

[avorancher]

I'm bringing this thread back. The intermittent problem continues with my backhoe although it seems a little better, but this morning something really weird happened.

The boom suddenly swung completely (and quickly) to the left by itself. I'm glad that nothing important was in the way. if I had been digging near the house I would probably have an extra doorway.

Anyway, it is now locked to the left side. I cannot move the control and it seems jammed. I cannot remove the safety cover because I cannot move the control level enough to clear the holes, but I can see under the cover enough to know that the piston on vavle is not moving up and down and I can see no mechanical binding on the lever linkage itself.

The boom is so tight to the left that I cannot raise up the stabilizer arm... so the tractor is stuck where it is unless I can release the pressure somehow. I turned overthing off and decided to wait for a while, then try to swing the boom by hand. I'm not sure I can get the stabilizer up before the boom returns to the left though.

 

[avorancher]

Another update. After letting things sit while I went to visit a dealer and get estimates, I came back home and was able to jiggle the safety cover off so I could see things better.

While moving the levers around, I heard a click and the lever moved correctly. I started things up and I don't think the backhoe has ever performed better. All problems gone.

I think I'll change the filter and fluids to be safe and keep a close watch for a while. It was really scary when that boom went flying without warning. I was running at full PTO speed, but I think it moved even faster than normal. Right now, I won't walk behind the backhoe without the keys in my pocket.

 

[john_bud]

Another update. After letting things sit while I went to visit a dealer and get estimates, I came back home and was able to jiggle the safety cover off so I could see things better.

While moving the levers around, I heard a click and the lever moved correctly. I started things up and I don't think the backhoe has ever performed better. All problems gone.

I think I'll change the filter and fluids to be safe and keep a close watch for a while. It was really scary when that boom went flying without warning. I was running at full PTO speed, but I think it moved even faster than normal. Right now, I won't walk behind the backhoe without the keys in my pocket.

It sounds like you have a mechanical issue with the linkage from the lever to the control valves. I don't know your system , but make sure that all the linkages are attached correctly (probably all the same way...) and that there is nothing bouncing around in there binding and jamming up the works. Might be as simple as a loose bolt or a rock getting jammed.

I would NOT use it at all until it was fixed, and I don't mean self healed! You could have smacked the house, but what if your wife had come by to hand you a sandwich and got squished by the hoe? Not safe in my book, but I am pretty old school when it comes to equipment safety. If there was something jamming up the works, there will probably be scratches on the linkages to show that. Look close and take pictures. Go to the K dealer and get a parts breakdown and a copy of the service manual pages for the linkage adjustment.

jb

 

[avorancher]

The linkage is very simple and everything looks fine. Since the intermittent swing problem seems to have also fixed itself also, I feel pretty sure the problem was in the valve itself.... probably not opening and closing completely. Of course I'm going under the assumption that both problems were related... the serious one could have just been a rock or woodchip caught in the linkage, but since I've been having problems for a couple weeks, it seems unlikely to me.

I bought the backhoe 3 years ago from a commercial plumber so it has been well-used.

I absolutely agree with you about the safety issue... and until I find a smoking gun, I'm going to keep looking for the cause.

Do they make a hydraulic oil additive to prevent sticking valves like they do for engine oil?