My 97 is on its 5th set of pads. I am having the rear shoes changed for the 2nd time. I have always had a problem with the van nose diving when you apply the brakes. In other words the front brakes are catching and not he rear.

I have them adjusted in the past but this problem has never seem to go away. Isn't there a proportioning valve that distributes the braking to all 4 wheels as need? Ive taken it to various mechanic shops and the dealership with the standard "rear brakes need adjusting" answer. I thought the self adjusters took care of this?

Any advice please?

The only thing I can think of is that there is an adjustable "star" nut that you can adjust in the brake drum assembly. Look on the back of the brake housing. On the bottom there is a rubber grommet that you remove. Then you take a long screwdriver and push against the star nut. It only goes one way to expand the shoes. To retract them you have to take another long thin screwdriver alont with the first screwdriver and push against a plate behind the star nut to rotate it the other way. It's hard to explain the procedure and a pain in the ass to do, but adjusting the shoes that way might give you the equal braking youre looking for. A haynes manual will help explain this better than I can. Good luck.