Hydraulic Cylinder Repack - Kubota KX161-2

[Beckbenj]

Hi All,

Walking out to the barn yesterday I find a streak of oil on the stick from the dipper cylinder. So it’s finally time to repack the cylinder.

Kubota does not offer the seal kit any longer. The do offer the individual seals / u-cup for sale, about $500 vs. the $300 cylinder reseal kit that was discontinued.

Even if I were to order the individual parts, I have a feeling the dealer may find they are discontinued as well.

So now the question: After disassembly, do I take the seals to a local hydraulic shop to match them up? I’m wondering how reliable this will be given the seals are compression set and not the same size as they originally were.

The other option that comes to mind is to measure the glands and the respective bores and look through a seal suppliers design manual to select the correct size.

Any thoughts on the best approach?

 

[Delmer]

The hydraulic shop shouldn't have any trouble matching them up. or you could order them yourself, but that could take a lot of time to figure out if you're not familiar with the catalog and different seal types.

 

[Beckbenj]

I’m assuming I can break the gland nut loose with the cylinder on the machine and then take it off after the nuts loose to repack?

I don’t have a cylinder bench or anything substantial to bolt it to.

 

[Delmer]

That's usually the way. Sometimes leave the cylinder in place and take the rod with gland and piston, just open the hose to let air into the base to pull it out. The machine is often the best base for removing the piston bolt/nut also. Any question, post a picture, I don't know Kubota cylinders, but somebody will.

 

[Beckbenj]

I’ve got the cylinder apart…piston wear bands are shot but luckily no damage to the piston or barrel.

I see that the piston retaining nut is held in place with a set screw, which has been staked in place. Any tricks on how too undo the stakes to allow the set screw to unthread? My initial thought was a dremel with carbide burr.

 

[willie59]

Normally just good pressure with an Allen key will release that screw, those punch marks don't make it difficult, they only prevent vibration making that screw shake loose, kinda like a self locking nut principle, like a Stover nut. And unless that cylinder used some very weird seal components, any hydraulic shop or seal distributor should be able to come up with compatible seals for far less than the numbers you've been given.

 

[chardengine]

Hi All,

Walking out to the barn yesterday I find a streak of oil on the stick from the dipper cylinder. So it’s finally time to repack the cylinder.

Kubota does not offer the seal kit any longer. The do offer the individual seals / u-cup for sale, about $500 vs. the $300 cylinder reseal kit that was discontinued.

Even if I were to order the individual parts, I have a feeling the dealer may find they are discontinued as well.

So now the question: After disassembly, do I take the seals to a local hydraulic shop to match them up? I’m wondering how reliable this will be given the seals are compression set and not the same size as they originally were.

The other option that comes to mind is to measure the glands and the respective bores and look through a seal suppliers design manual to select the correct size.

Any thoughts on the best approach?

Hi

What do you need help for your machine? I am a seal kit specialist I can assist.
My website is www.mxpseal.com

 

[Beckbenj]

Hi

What do you need help for your machine? I am a seal kit specialist I can assist.
My website is www.mxpseal.com

Thanks for the offer. I would prefer to look into this locally first.

 

[Beckbenj]

I’ve got the piston off but noticed something strange. When loosening the retaining set screw, the piston/nut started to unthread with very little torque. I had marked the orientation of the nut to the shaft so that when it’s reassembled I could put it back in the same position in lieu of torquing it to 1,475 ft-lbs (no torque wrench available).

Now with the piston seeming to have little torque on it, I’m not sure that I can use the “return to original position” approach.

The torque called out in the service manual is 1475 ft-lb for the cylinder nut.

One option that came to mind is to figure out a length of pipe needed and stand on it, which would produce a known torque.