Hydraulic cylinder diassembly - stuck piston

Clamp the cylinder in a vice and use the rod and piston assembly as a slide hammer to drive the head out of the bore. Most of the cylinders of this style I have seen use a one piece ring to retain the head. I think yours may be broken and this may have caused deformation and is why the head won't come out of the bore without force. Steve

Standard problem when rebuilding cylinders. At least the ones that use a internal groove to retain the gland. Best method is to first drive the gland into the cylinder far enough that you can grind the burr off the outside edge of the groove (it will have developed from the ring pushing against it). Then rig something up to pull the cylinder apart (this is the hard part for most people). I use my large vise (very large and mounted firmly to a large pipe buried 5' into the ground and attached to the roof of my shop) and pull against another pipe which also supports my shop with a come along. It will likely be difficult to get out even with this method. The reason is that the o-ring seal on the outside of the gland will get into the groove and try to lock the gland in place.

I've know some people in the construct trade to use two large loaders to pull cylinders apart. You might could work up something with your truck and a solid tie point.

As always, I do not have relevant experience, but my suggestion is to find a hydraulics shop to do it for you. It may not be very expensive. I am fixing a lightly out of order Cummins A series diesel, it had a bad radiator (bashed in) and repair it at a radiator shop was only $40.

Thanks everyone for the input, I rigged up a couple of trucks and pulled it apart after grinding the burr down. Worked great! Again, I appreciate all the help.

Terry