Air Brake Automatic Slack Adjuster problems of the 1999 Chevrolet Tahoe

Since purchasing the vehicle (dealer demo) in late 1999, front rotors have been turned four times and replaced once due to warping. This problem has been attributed to the fact front brakes are doing all the braking. It seems the rear brake adjusters do not hold adjustment for more than a few applications of the brakes. The rear pads have never been replaced because they are not worn due to a lack of application to the drum. The vehicle has had the adjusters cleaned several times and the brakes have worked for a few days only to have the rear brakes lose adjustment again. Obviously this is a serious saftey issue as the vehicle takes much more effort to stop its motion. Athe replacement cost of the front pads and truing of the rotors has been expensive. The cost far higher than normal for most vehicles in this class. A very near accident was barely avoided this past week due to a loss of stopping power as the rear brakes do not assist the front discs. Also the emergency brake does not hold the vehicle. When firmly applied a few weeks ago, on a slight grade, the vehicle began to roll.