The FEL cylinders for my L275DT are seeping too much for me to ignore any longer. The sealing surface of the rods/pistons are undamaged, so I'm assuming that it was just dirt buildup over time that has worked into the seals. I've not taken anything apart to verify that the seals aren't damaged or cracked from old age, however. I have no idea how old the seals are.
What are the odds that they just need a disassembly and cleaning vs replacing the seals?
What's your time worth? You have to disassemble the cylinder to get to the rod seals. My experience has been that the wiper seal hardens with age and then let's dirt in. So the wiper has to be replaced.
Then to clean the rod seal, it needs to be removed. I've not found a way to do that without damaging the old seal, so it would have to be replaced.
These are wear parts. They are sacrificial to the more expensive rod and cylinder. And they are sold by Kubota in sets, not individually, so it doesn't make sense to do a partial replacement. You might find suitable components from non-Kubota sources so you could replace only selected seals. But if you don't replace the piston seals while you're in there, they're likely to start leaking and then you get to disassemble the cylinder again.
Also, all the cylinders I've worked on had piston rider rings, and some have rod rider rings. These serve as bearings to keep the moving parts centered in the bores, preventing metal-to-metal contact and prolonging seal life. So if you keep worn rider rings, at least shortened seal life can occur and, worse, cylinder, rod, rod cap and piston wear caused by rubbing can take place.
All in all, it's prudent to replace everything while the cylinder is disassembled.
