I've got an F800 digger derrick truck that I'm outfitting to be a service truck/welding rig/small boom truck. Got to repack the leaking boom extension cylinders, it's not a crane, but I'm guessing that repacking the telescoping cylinders in a crane would be kinda similar. This may be a stupid question, never done this before, but what's the best way to get to the cylinders? The boom has to come apart somehow, and I'm not exactly sure how. I'm assuming that I've got to extend the boom, unpin the first cylinder (accessible from the rear of the boom), then pull the second and third stages out of the base, then I'd imagine I'd have access to the pin that attaches the first extension cylinder to the second stage, unpin it, remove the cylinder, repack and do basically the same thing again to get to the second extension cylinder. Seems like an awful lot of work to just repack a cylinder, but like I said, never done it before. As usual thanks for any and all info.
On truck cranes, the boom cylinder unbolts at the rear, then you pull the boom sections from the base to get at the cylinders. Grove recommends pulling the whole boom from the crane, then splitting sections. I've always left the base on the crane, and then pulled the sections out with a forklift,far enough that I can grab the rest with another crane, then set it on a trailer or blocks for the rest of the disassembly. I always thought leaving the base in the crane makes it easier to pull the other sections out. If you pull it all off, then you have to try to anchor one end and then pull the other. Biggest problem is if you don't have another forklift/crane to lift and pull the boom with. If you have to hire a little help to lift the stuff, it may be cheaper to find a wrecker than a crane.
Thanks, for the info, really apprciate it. I originally I was going to just pull the whole boom off, but relized if I could leave it on it would be easier. I have an old 40 ton P&H and a 25k Hyster along with normal farm stuff so I should be able to handle moving the boom around. If it stays dry, might be able to try next weekend.
Also- I don't extend the boom before pulling it apart. Then you have a extra 20' of cyl sticking out. Leave it scoped in, unpin and block up the cyl, if it needs it to keep it from falling down in the boom (4x4's cut small etc.) Measure your boom so you know where center is, hook forklift on tip, pull until 3/4 of the boom is out. Then because you measured it (thinking ahead) rig your crane on the center of the boom, spreader bar helps. At that point if you've got a flat yard or concrete, I find it easier to leave the crane (the one holding the boom) and forklift in place, and back up the rig that your pulling boom from. Slow is the key, and make sure you have a little but not too much tension on the crane holding the boom, so it doesn't fly up or fall down when it comes out the last bit. Also if there are adjustable wear pads, pull them, or back them clear off, before pulling the boom.
Excelent advise, will do just as you say. Thanks a bunch.