If store out side the rod all way in should be ok the hose
outside covering is no indication but if covering bad and wire inside rusted the inner tube as its call inside may bust. clean quikdisconect is must they click together very easy if there no pressure on male are female ball in couplings new male end and hose would be for as I go if can't clean ends. messing this type think good place to get oil srayed so sespect pressure all time.

I would have those hoses inspected by someone very familiar with hydraulics. A friend who worked on tow motors was next to a hose that sprung a leak and he got injected with hydraulic fluid. It is a very serious injury and avoiding it would be well worth the cost of new hoses.

I'm with dmullen on this. I'd take it in to a regular hydraulic shop that makes hoses/lines and have them pressure test it and purge out the old fluid. No sense in risking injury or contaminating your tractors hydraulics.

Personally, I have a lot of equipment with weather checked hoses and they all work fine. I live dangerously (or moneylessly) and only replace hoses when they spray fluid or leak heavy. But if you are concerned about it, just replace them yourself.

Take the questionable hoses off. This will be messy as the lines are filled with hydraulic oil. You'll be able to tell if your fluid is contaminated when you take the lines off. I'd recommend having an ice cream bucket or something to catch the oil. Take the pioneer tip(the part that plugs into the tractor) off first and put the hose end in the bucket. Take the other end off and lift it to drain the oil into the bucket from the other end. On a splitter with it's own control lever, there should be 4 hoses - 2 from the tractor to the control and 2 from the conrtol to the cylinder. Keep track of where each of these go.

I wouldn't worry about purging the cylinder if the oil is transluscent brown to dark brown. If it's milky, it had water, if it's chunky, the last tractor never had it's hyd oil changed and sludge made it into the splitter. Either way, I'd put the hoses back on loose with the other end in your catch bucket and push and pull the cylinder by hand to purge it. This will take a little muscle. If the splitter has it's own control lever, I'd bypass the control and hook the long hoses to the cylinder itself to purge. Don't worry about getting every last drop out. The tractor has filters and its hydraulic oil should be changed every year or two anyway.

Take the hoses to an implement dealership. They will either have ready made hoses on hand or can make them to order while you wait. Since the hoses have air in them now, the splitter may not work right the first few times you run it back and forth. It'll bleed itself out shortly and work properly. When you run the splitter for the first time afterwards, you'll need to check and top off the tractors reservior with hydraulic oil.

If this seems like more of a task than you can manage, then I'd take it into a professional.

Good luck!

I agree all above I started building wood splitters in 1968 hoppy with income out of junk parts form bulldozer are track equipment torch to cut out old c-frame as beam back then all was homemade splitters. Hydraulic hose fitting were reuseable ends this before press-on fitting. Never repair splitter hydraulics until leaks they almost never leak build from old parts.