Failing packing ruined bucket cylinder on Deere 7 backhoe

dsmau · May 30, 2011

Hi,
I started using the Deere 7 backhoe that I bought over the winter. It is at least 20 years old I think. After 10 minutes of using it, I noticed that the bucket cylinder would not retract anymore or would do so extremely slowly or with help. I went back to the garage and disassembled it. I had never done anything like that but I figure it should not be so bad. I made my own Spanner Wrench and it went well.
I was hoping to just find the failed seals/packing but instead it seems I found that the piston had rubbed against the tube in a few places and I am afraid it is ruined. I don't know much about hydraulics. I will head to the local hydraulic shop tomorrow and have them take a look. What I thought would be a quick and cheap fix will probably end-up being a costly replacement. Dimensions are 2" bore, 13" stroke and 1" rod.

SixHoeBob · May 30, 2011

Are you sure the rod was not bowed? That might cause the piston to rub the cylinder wall.

dsmau · May 30, 2011

SixHoeBob said:
Are you sure the rod was not bowed? That might cause the piston to rub the cylinder wall.

It looks very straight to my eye. The packing was so bad it went in between the washer and the tube on one side so I suspect the opposite side was pushed against the tube and rubbing. Again I don't know much about hydraulics...

Rocwin · May 31, 2011

At this point it is probably cheaper to buy a new cylinder, especially one so small. If you fix the barrel you still need to be sure about the rod (don't eye ball it), then you'll have to measure up the piston because it is damaged and likely is out of tolerance.

Unless the cylinder is hard to find, or overly expensive; if two components are bad it is cheaper to just replace it.

dsmau · May 31, 2011

Hydraulic shop confirmed that it was shot.
I purchased a generic 14 inch cylinder and had them shorten the rod 1 inch to be closer to original cylinder retracted length. All together with fittings it got to right around 200$... I'll put some green paint on it tonight and put it back in place ASAP. Looking forward to see how it will work now.

Only concern left: What about the fine metal shavings in the system? Should I be concerned and what can be done if anything?

Thanks for the help!

evo803 · May 31, 2011

dsmau said:
Hydraulic shop confirmed that it was shot.
I purchased a generic 14 inch cylinder and had them shorten the rod 1 inch to be closer to original cylinder retracted length. All together with fittings it got to right around 200$... I'll put some green paint on it tonight and put it back in place ASAP. Looking forward to see how it will work now.

Only concern left: What about the fine metal shavings in the system? Should I be concerned and what can be done if anything?

Thanks for the help!

Change the filter and hydraulic fluid.

dsmau · May 31, 2011

evo803 said:
Change the filter and hydraulic fluid.

Change before I do anything else with the tractor? Backhoe is off now. Any danger?
Or perhaps I should use the backhoe a little so the shavings actually go in the filter and then change the oil?

What do I do with the old oil? No way to reuse it ever?

Egon · May 31, 2011

The packing may have been damaged by water/ice at some point in the past.

It may not hurt to flush out all your hydraulics now.

evo803 · Jun 2, 2011

dsmau said:
Change before I do anything else with the tractor? Backhoe is off now. Any danger?
Or perhaps I should use the backhoe a little so the shavings actually go in the filter and then change the oil?

What do I do with the old oil? No way to reuse it ever?

On a 20 yr old tractor I would be changing every fluid and filter just to make sure ! If you use the backhoe you could be circulating the metal and damaging more seals etc... I would not re-use the oil just recycle it.