"I would expect to unscrew the end cap (pardon that I don't know all the correct terms for their respective parts)."
I tried to clarify some terms in the marked up pic.
"Once the end cap is unscrewed, I would anticipate seeing something like the picture above. Some more of the cylinder rod with the "piston" at the end and several gaskets on the piston."
Correct - except those gaskets would be called "rings" or "seals"
"I would imagine, the gaskets get wrestled off somehow, new ones installed and the whole assembly gets reinserted back into the cylinder, screw the end cap in and "done", easy peasy."
Correct, except for the "easy peasy" part - usually not so much, due to heat/cold cycles, time, being put back together previously without anti-seize lube on threads, etc...
"I don't understand the comment above about pulling a 4" piston through a 2" hole?"
This was probably due to Billrog/my misunderstanding of terms - What I meant was that, unless you take that gland (AKA "end cap") out, you cannot just take out the rod because the piston is (hopefully) still attached to the rod, and the hole thru the gland is only the diameter of the ROD, not the PISTON.
"I would think the whole ensemble would come out with the end cap dangling during the process."
Correct.
"I wouldn't need to actually remove the piston from the rod would I ??"
Sorry - I am ***-u-me ing you found the leak because it's EXTERNAL (dripping) rather than INTERNAL (can't see it but cylinder is weak operating, bleeding past the piston seals) - if so, then the main seals you need to replace are the ones INSIDE THE GLAND - and the ONLY way that can be done is to completely remove the rod from the gland once you've removed the "whole ensemble" as above -
And that requires removal of the piston from the rod, since the welded end of the rod won't go thru the gland and the OTHER end can't either, unless the piston is removed.
Item# 5 is the front wiper seal, #6 is main seal, and there is sometimes another rear seal (not shown in diagram) - ALL these must go INSIDE the gland, which
can't happen unless the rod is out of the gland. These are the items that will cause an EXTERNAL leak if bad -
Also, in some cylinders (older Case, for example) the piston is split (see items 12,13,15) - regardless, since it's likely your GLAND seals are bad, the piston has to come off the rod in order to get the rod out of the gland.
From an optimist's point of view, you might NOT have to remove the cylinder BODIES - I didn't when I did the swing on my Case - I centered the boom, pulled the pins that hold the rod ends to the swing tower, unscrewed the glands, broke hydraulic connections so pistons could move, hooked a comealong into the rod eye and pulled the entire rod/gland/piston out of the cylinder tubes.
Next - big vise, big table, smooth metal "shoes" over vise jaws, grab ONLY the flattened sides of the rod end, 1-1/2" impact socket/big air impact gun, remove nut retaining the piston, slide the gland off the rod, match up new parts in kit to what was removed, reverse the procedure to re-assemble.
NEVER touch the rod with anything metal - any part of the rod that isn't perfectly smooth will cause you to start OVER with new seals
Also - the Case cyl's use an internal rod seal (item#6) that's usually a BEAR to get in and out - it goes into a deep groove inside the gland. Getting the old one out will usually take a couple of "hook picks", something like this
Pick and Hook Set 7 Pc
Getting them out isn't usually as hard as getting the new one back in - my method for that is (1) dunk the seal in nearly boiling water for maybe 10 seconds to soften it - (2) as soon as it's not painful to touch the seal, grasp it on one side with thumb/finger, then use SMOOTH-JAWED (no sharp edges or serrations) pliers and grasp the OTHER side of the "donut", and TWIST the seal (in the same plane, this will cause the part between your fingers to become smaller diameter, with a small "inside out" half-circle where the pliers are) - then, holding the seal in this "omega" shape, insert the part held in your fingers into the big groove in the gland, twisting the pliers back and forth til MOST of the seal is where it belongs - finally, smooth out the seal with a finger so ALL of it is in the groove.
Re-assembly - wet a finger with hydraulic fluid and pre-lube the seal and wiper before attempting to insert the rod back into the gland.
I may have forgotten a step or two, feel free to ask about anything that isn't clear... Steve
