Cold weather and mine, including new ones right out of the box, bleed down over time allowing the seat to bottom out and don't want to air up in the winter. Solution is to get out of the seat and pump it up to full up position, then adding more air, testing the tension and when firm, then sit on it and adjust accordingly. Once it warms up it works normal. I have been all over my original, had it out of the tractor, on the work bench, soapy water testing and all and no luck. I bought a new one, different brand but parts seemed to be of the same design...like a universal pumping system, just different frame, size, and bolt pattern, and was surprised to see a new one acting the same way telling me that if it has a leak, it's going to take submerging in a liquid which is impossible......I think!