Replacing rear shocks on a Chevy Blazer is rather easy. The purpose for this routine maintenance repair is to increase tire life and improve vehicle stability. As shock absorbers wear, their ability to hold the tire to road decreases, causing a bouncing effect that eventually will cause cupped tire wear.
With the vehicle on a flat surface, jack the rear end up with a floor jack, and support it with jackstands. Place a set of wheel chocks in front of the front tires, to keep the vehicle from wanting to roll forward and possibly slide off the jack stands.
Remove the top and bottom bolts on one of the shocks. Place one hand on top of the shock, while holding the bottom with the other. From the top, push in a downward motion, compressing the shock so that you can remove it from the vehicle.
With the new shock in hand, start the bottom bolt by hand, and allow the shock to decompress while guiding it to its mounting point with your other hand. Tighten both shock bolts to factory specification.
Repeat Steps 2 and 3 to replace the other rear shock.
