I have a trick I use for the rear center sliders (these are the ones that typically go 1st). I take PEX tubing (used for potable water systems on RVs) 1/4"ID X 3/8"OD, and make my own bushings. They won't roll like the old ones, but work a heck of a lot better than steel on steel and it's cheap. It's a tight fit, so even the pins that are worn down will still grab onto the pipe. It takes a little force to push the pieces of pipe on good pins, but it's managable. Here's some pics I took last time I did it. This is on a Previa, but the center rear rollers are the same on the vans. Tim