You can adjust the parking brake on your Chevy Astro Van in your own driveway or garage, using a couple of simple tools. Doing the repair yourself will save time and money. The emergency brake is designed to hold the vehicle in place when parked on an incline. If the vehicle slips, you know it's time for an adjustment. Just note that the parking brake is only slightly effective at stopping the Astro during an emergency situation.
Get underneath the vehicle and find a long bolt that houses the rear brake cable. This bolt holds an adjuster nut. Grip the bolt with the vice grips to keep it from spinning around as you adjust the nut.
Rotate the adjuster nut with a wrench, turning counterclockwise, if the cable is too tight. If the cable is too loose, you turn the adjuster nut clockwise.
Slide out from under the vehicle. Park it on a downhill incline and engage the parking brake. There should be no slipping if you did the adjustment correctly.