To lower a 1986 Chevy truck, support the vehicle using jack stands, replace the shackles using the rear axle block and kit, and replace the front spindle using the spindle-lowering kit. Replace with the standard parts on the vehicle's passenger and driver's sides.
After supporting the Chevy truck's frame with jack stands, detach the wheel lugs using a lug wrench, and remove the wheels from the hubs.
To replace the shackles, use the jack to prop the vehicle's rear axle, and undo the four nuts beneath the mounting plate that attach the shackles to it with a 1/2-inch drive socket. Force the shackles upwards and away from the mounting plate, and then pull them off the rear axle.
Raise the jack further, and position one suspension block between the leaf spring and the axle. Attach the replacement shackles by reversing the removal process, and secure to the mounting plate using the nuts given with the axle-lowering kit.
To replace the front spindle, remove the bolts of the brake caliper with a ratchet to which a hex bit is attached. Detach the caliper and the brake disc, and let the former hang to the spindle's side. Remove the brake disc from the wheel lugs, and take out the metal cover of the wheel hub.
Undo the nut at the hub's center with a socket wrench, and remove the hub from the shaft of the spindle. Detach and let the tie rod of the spindle's steering arm hang to a side. Using a jack, prop the lower control arm, and undo the ball joint nuts at the top and bottom.
Next, pull the upper control arm upwards, take out the spindle, and replace with a standard one. Finally, replace the tie rod, wheel hub and brake parts.