You didn't mention which brand leveling jacks you have, but on our Power Gear stabilizer jacks, the springs are hooked on the lower end, but a long bolt pulls and fastens the top end of the spring to the plate. All I have to do is unscrew the bolt, remove the spring and re-install.
Here is a quote from Power Gear on the subject of lubrication:
Hydraulic jacks can be cleaned and lubricated on the chrome rod that extends out from the barrel of the jack with silicone spray. If your jacks are equipped with Zerk grease fittings at the bottom of the outer barrel then lubricate them with all purpose lithium grease. Do not use WD-40 as it can damage the seals in the jack assembly.
Also, some owners who travel on cold areas have changed the hydraulic fluid in the stabilizer system to Mobil DTE 11M, Texaco Rando HDZ-15HVI, Kendall Hyden Glacial Blu. These fluids have greatly increased the jack return speed.