Okay, pretty simple but a little vague from the drawing, but you can tell by looking at it. Put the cylinder in a good holder. If you put it in a vise, don't squeeze too hard or you may dent the housing. Do that, it's junk. Unscrew the cap nut, # 2. Now, pull the rod all the way out until it stops. This is the piston, #11 hitting the gland, #6. Now, push the rod back in about 12". Pull it out fast and hard. This may take a few times. You have to unseat the gland from the housing. Use the rod kind of like a slide hammer to unseat the gland. You will want to replace #8. There are wear bands in here, #'s 7 and 12, but unless they're damaged, don't worry about them. #10 says it's a retainer, but I don't know what kind. See below--->** You will need #13, I suspect this is what's bad.** You may have to put the rod end in a good vise to remove the piston nut. But, if you don't have to remove the piston to change the seals, just leave it alone. For a customer, even though this is a fairly new cylinder, I automatically change all the seals. But for you on this, just do what you have to. Unless, you really want to learn, then remove the piston and the gland just to peek at everything to see how it works. You won't hurt anything if you do.
A little cylinder terminology. 3 is called the wiper. It is installed backwards of what you would think. It's function is to keep stuff out of the cylinder, not to keep fluid in. That's why it looks backwards.
4 and 5 are your rod seals. These come in all different configurations, from a simple o-ring, to a U seal, to a set of V packings. They all work, just pick your poison.
6 is the gland. It holds the rod seal and outer o-rings. It can neither slide in like this one, or it will have threads and screw into the housing, eliminating the need for #2.
8 is an o-ring and a back-up ring. Back-up ring is kind of rectangular and goes on first, then the o-ring.
7 and 12 are wear bands. Some have them, some not. Depends on the cylinder function and seal style.
11 is the piston. Piston seals go here, it usually is held onto the rod with a nut or bolt, sometimes they are threaded and screw onto the rod and held in place with a set screw.
13 of course, the piston seals. Many configurations. Some better than others but you have what you have, no changing them.
9 are o-rings that seal the inside of the piston to the rod so fluid can't bypass there. You could probably leave them out and never have a problem, but change them anyway, cheap insurance.
When assembling, if you have any doubt, the open part of the V or U style goes towards the pressure you want to seal.
Coat anything flexible with good clean oil before you assemble. Keep the assembly area clean............ no,............ i mean CLEAN! Like surgical clean. Really, I mean it. Any dirt on a seal is like sandblasting your car's paint. Yes, put 2,000 psi behind a piece of dirt, instant leak.
I think that should about cover it. You're lucky I'm too sore to get up today or this would have been short and sweet.
Good luck, any questions, feel free to ask. You might want to print this and refer when you do this.
Andy.
**13 is called the back up ring, 12 looks like a wear band in the drawing, but they are calling it a packing bushing. Which, may mean it's a packing (seal), or a bushing( wear band). Or, it's both.
