Need to replace this cylinder - how to measure?

[lhfarm]

This is the cylinder off my antique jeep with a Newgren hydraulic lift. These pictures are from a few years ago. The end attaches to the frame with a 1" pin. The rod fits in a 1" hole in a block. I'm looking for a modern single action cylinder to replace it. How can I measure it so that I can match it to available cylinders? I'm not sure the measurements in the photos are accurate - not sure it was fully extended.

 

[LD1]

Typically you measure extended length, and retracted length. Thats from pin center to pin center. Both those numbers are important.

then the difference of those numbers is stroke length.

You also need to know the bore diameter. You want the correct bore. Larger bore will be slower and more powerful. Smaller will make it faster but weaker.

You will want to know the rod diameter.

And finally, all the details of the mounts. Pin diameters, width of the eye or clevis (where the pin goes through), etc.

baileynet.com usually has a pretty good selection of cylinders. And if you cannot find anything to match up, have you considered rebuilding the existing cylinder

 

[lhfarm]

Thanks. Is it possible to measure the bore, without disassembling the cylinder? Or at least can I get a good approximation with an external measurement of the case?

When purchased, the cylinder case was rusted through. I had at a great expense the cylinder rebuilt using the original components I've chronicled my issues with the lift in a number of post here. Unlike modern cylinders, this one doesn't have a port or drain to the air. A hose from the bottom of the cylinder goes back into the top of the reservoir. If I leave the hose unhooked, I get fluid shooting out (not a lot) when the lift is lowered (gravity down). I have been chasing a leak that is causing the fluid to foam. Not sure it is related to the cylinder, but at this point I want to replace it.

This is a long way of saying that I don't want to rebuild this cylinder if I can find a replacement.

 

[LD1]

Do you have any records of the last rebuild? Whoever did it would have to know what the bore size was.

If not....for a cylinder that size, the approx wall thickness would be maybe 1/4" or 3/8". So measure the OD of the cylinder and take off 1/2" to 3/4" or so. Whatever the closest nominal size is to that

 

[lhfarm]

Did the rebuild over a decade ago, so doubt I still have paperwork. However, really appreciate your suggestions and think I have enough info to go shopping.

Thanks again,

 

[npalen]

It must be a fairly thin wall cylinder if it was rusted through previously.. My guess would be 3/16" wall. Measuring the circumference and dividing by 3.14 would give the outside diameter. Then subtract twice the wall thickness for bore diameter as mentioned above.

surpluscenter.com might be a possible source for a replacement cylinder.

 

[npalen]

Thanks. Is it possible to measure the bore, without disassembling the cylinder? Or at least can I get a good approximation with an external measurement of the case?

When purchased, the cylinder case was rusted through. I had at a great expense the cylinder rebuilt using the original components I've chronicled my issues with the lift in a number of post here. Unlike modern cylinders, this one doesn't have a port or drain to the air. A hose from the bottom of the cylinder goes back into the top of the reservoir. If I leave the hose unhooked, I get fluid shooting out (not a lot) when the lift is lowered (gravity down). I have been chasing a leak that is causing the fluid to foam. Not sure it is related to the cylinder, but at this point I want to replace it.

This is a long way of saying that I don't want to rebuild this cylinder if I can find a replacement.

I'm a bit confused when you say "A hose from the bottom of the cylinder". Are you referring to the port on the left in the picture? If so, that would be the "breather" port which makes sense that it would go back to the reservoir. I don't understand, however, why you would get "fluid shooting out" when lowering the lift. There should be a slight vacuum in this hose when lowering the lift. There shouldn't be any oil in the hose unless the piston seals are leaking oil past under load.
Does the 3 point lift stay up when raised or does it "leak down" fairly fast? I would consider removing and disassembling the cylinder to check the bore and stroke dimensions.

Edit: The breather hose going back to the top of the reservoir may draw some fluid out of the tank when the lift is lowered. This would help lubricate the rod end of the cylinder. There would probably have to be a suction tube connected to the reservoir port and extending down into the fluid for it to draw.