Bleeding brakes on GM trucks manufactured from 1995 through the early 2000s can be challenging due to the Kelsey-Hayes EBC310 ABS system. This system features three sections—one for each front wheel and one for the rear axle—each with an isolation valve and a dump-valve/low-pressure accumulator. The accumulator, crucial for proper bleeding, is located behind the dump valve, making it inaccessible for traditional bleeding methods.
The factory-approved procedure for bleeding these brakes requires a Tech 1 Scan Tool to cycle the ABS system. This cycling process flushes fluid and air from the low-pressure accumulator. Without the scan tool, accessing and bleeding this component is impossible. However, there’s a workaround some mechanics employ, often referred to as the “shade-tree” method.
This alternative method involves driving the vehicle on a gravel or snow-covered road and forcefully applying the brakes to lock the wheels, triggering the ABS to cycle. While this might seem like a solution, it comes with significant risks. First, the brakes must be functional enough for safe driving to the chosen location. Second, cycling the ABS in this manner can release trapped air from the accumulators into the brake lines, potentially compromising braking performance drastically. Even if successful in activating all three circuits (left front, right front, and one rear wheel), subsequent bleeding is required to remove any remaining air introduced into the system.
An Actron Abs Auto Bleed Scan Tool offers a safer and more effective solution. These tools can activate the ABS system, allowing for complete fluid exchange and air removal from the low-pressure accumulators. Using a scan tool eliminates the risks associated with the “shade-tree” method and ensures a thorough brake bleed, resulting in optimal braking performance.
For those working on GM trucks from this era, investing in an Actron ABS auto bleed scan tool is highly recommended. It’s a crucial tool for properly maintaining the braking system and ensuring safety. While the “shade-tree” method might seem tempting, its potential dangers make it a risky proposition compared to the controlled and efficient process provided by a dedicated scan tool.
Bleeding ABS systems requires specialized knowledge and tools. For a more in-depth understanding of this procedure, refer to the following resource: Brake & Front End Magazine, “Bleeding ABS Systems” by Bill Williams (July 2005) – http://www.babcox.com/editorial/bf/bf70518.htm
