Might be confused with sometimes the jacks will freeze to the ground. If the jacks get any kind of moisture under the jack pads, the springs will not have enough force to pull the jacks back up if they are set down on asphalt or concrete. If on dirt it will also sometimes not release but will usually bring up a mess of earth if it does. I used hot water to get me unstuck once but if I suspect freezing weather I now usually put a block of wood under the jack pad and since the water will soak into the wood and not build up around the pad as bad it will usually release the jack and after I pull away I can go back and beat the block with a hammer and it will usually break free as well. I've also sprayed WD-40 on the bottom and usually had luck with that also.