The following in italics is a portion from Volvo Tech-Net Notes No. 55-02 Date: 5-20-2003 Subject: Parking Brake Adjustment. I had this done when the parking brake wasn't releasing properly causing the brakes to overheat.
Description: The Parking brake should have a range of 4 - 6 clicks when fully depressed (Using normal pedal force). If it is found that the range is less than specified, it is recommended to install a balancing spring (PN 1212200) to the self-adjuster mechanism.
4. After the spring is installed, it will now be necessary to reset the self-adjuster on the parking brake pedal assembly. Locate the Release spring (see illustration, No Disassembly Required), and push it forward slightly (approx. 1/4 inch) using a screwdriver, hold it forward for approximately 5 seconds. This will allow the balancing spring to pull back on the self -adjuster.
5. Depress and release the Parking Brake 10 times (this will allow the self-adjuster to reset.
Note: "Release spring" mentioned above is a small metal tab located near top of brake pedal arm. Balancing spring was installed near primary brake cable yoke inside center console.