1998 Chevrolet Astro suspension problems

I own a 1990 chevrolet astro (van) and a 1998 astro. The 1998 van is 18 inches longer then the 1990 . The extra 18 inches were added to the same suspension as the 1990 astro. The 1998 astro has a bad sway to the rear suspenison weather you have slowed to turn into to a drive way or making a curve on the highway this van would still be rocking after you had completed this task. I have never been car sick in my life but sitting in the third seat would make you feel ill. On the 18th of feb.

While braking at low speed the ABS would cause extended stopping distance. Dealership was notified, but did not resolve the problem. Front wheel speed sensor replaced. Left front window hangs when going up. Window tracke lubed. Pads and rotors replaced. Rer brake adjusted. Brake pedal kicked up when almost to a stop. Replaced brake calipers/rotors/ backing plates and removed sensors and cleaned rust build up on sensor and hub assemblies. Both idler amrs and front and rear shocks were replaced due to front end play.