If your parking brake isn't working correctly (grabbing too little or too much), you'll need professional help. The problem isn't a simple adjustment; it's likely one of the following:
* Worn brake shoes: The parking brake shoes inside the rear rotors are worn down. These need to be replaced.
* Weak return springs: Springs may be broken or weak, preventing the shoes from releasing properly. These also need to be replaced.
* Internal mechanism failure: A component within the parking brake assembly might be damaged or malfunctioning.
* Contamination: Dirt, rust, or other debris may be interfering with the mechanism.
Attempting to "adjust" it yourself could lead to further damage and potentially dangerous driving conditions. Take your Impala to a qualified mechanic or brake specialist. They have the tools and expertise to diagnose and fix the problem correctly. They'll likely need to disassemble the rear brake assemblies to assess and repair the parking brake system.
