I had the springs replace two years ago, and about a year ago the jack started retracting slower and slower, until they quit about half way up. I tried what the HWH tech said at a rally, dry silicone spray, but it didn't help. I fabricated a piece of wood with a lever that gets them up, but finally got underneath, cleaned the seals with a toothbrush saturated with WD40, and wiped the jacks with it also. Since then, an occasional cleaning and wiping keeps them operating smoothly. BTW, I'm a full timer, and the jacks get raised/lowered an average of once a week. Personally, I think it's an inherent design problem, and I'm not going to replace any parts until the jacks lock up and won't move.