How do you measure or tell ?

HuskerJ - 12/20/2023 06:20

From your picture I would guess it would be a 20" cylinder. Cylinders are measured by bore, and stroke length, and usually collapsed length.
Bore explains itself, it is the diameter of the inside of the cylinder, which would be the 4 in the 4x20.
Now, the 20 in the 4x20 is stroke length. If you look at your picture, you can see the cylinder is about 22-ish inches between the endcaps. Inside the cylinder there is a plunger that I will guess will be roughly about 2 inches thick, which leave a 20 inch stroke.
Whenever I replace a cylinder, I try to measure its collapsed length and fully extended length from the center of the mounting pins on each end. Subtract one from the other for the stroke length. It is also good to know the distance between the pins because some cylinders have longer yokes than others, and some have the rod extend more than others when fully collapsed.

This is the correct response. Different manufactures have different retracted lengths so a 4x20 from company A will not be the same as a 4x20 from company B. Measure the retracted hole to hole and the extended hole to hole and find a cylinder that matches it.

I'm not sure what's wrong with your cylinder but I good hydraulic shop should be able to rebuild that cylinder for less than half the cost of a new 1. If you're planning to replace it with something cheap like a Cross then I would just suggest rebuilding it because what you have is likely higher quality than what it will get replaced by.