Thanks John. tilt works fine and the side cylinders go up and down fine. As soon as it comes down to the center cylinder stage, there is a sharp thud. Almost as if there is something obstructing the tracks. We loosened the bottom hydraulic and took off the spring and star piece at the end of the spring. And still the piston will not come down and there was no oil in the cylinder even though the piston was all the way to the top. Francis