2000 SEL Lumbar problems

I have a 2000 Windstar, and it has the power lumbar which consists of a small air pump and a bladder behind the seat. The problem I have is the baldder will fill up fine, but as soon as you let go of the button the air starts escaping, and will go flat in about a minute.
Is there some sort of check valve in the line somewhere, or do you have to replace the whole unit??
Also, the foam on the drivers side seat bottom is totally flattened out, does anybody know if the sell replacement foam for the Windstar seats?

There is a plastic tube that runs from the pump, along the seat base, and then up the seat back to a bladder. On my 99, the tube was worn through (fretted) at the point where the seat back adjusts.

Fill the bladder up, then listen carefully for the leak. In my case, I was able to pull the cloth cover on the seat away enough to see the leak. I cut out the bad part of the tube, then used some tubing from Home Depot for the patch. It has worked perfectly since then. Hint: do not try to patch the tube with tape, as it will not hold for long--cut out the bad part.

As for the seat foam, must auto upholstery shops will fix this for you.

Do you know what side of the seat this tube runs up? By the center console or by the door?

It runs up the side by the center console on my 99.

I found the leak, and like yours it is in the tubing, except higher up in the back, I can barely get to it. Do you know what size tubing you got to replace it? I fear that if I trim off the tubing, I will not get the end back out of the seat back. I did see on the bottom the black tubing goes directly into a silicone fitting. I wonder if there is a similar fitting in the back?