Phil, you are correct, and the photo in your other post is what the base of my jack looks like (though the perspective is a bit odd, and exaggerates the curve).  My jack works exactly as you described.  However, using a 12"x12" wooden base under the jack to stabilize on soft surfaces does not interfere with the "self stabilization" mechanics of the jack, and is a good thing to do.  It is even recommended in my owner's book.

mcneely

---- Ben T <syncro@GMAIL.COM> wrote:
> Phil,
>
> IIRC, the jack base is designed so that it can 'rock' to the optimum position as you lift the van.

(stuff cut as the mods request)