For owners of ’95 through early 2000s GM trucks, performing a brake bleed can sometimes turn into a perplexing task, especially when dealing with the Anti-lock Braking System (ABS). Many find themselves asking if specialized tools, like an Actron Abs Bleed Scan Tool, are essential for a complete and effective brake job. The truth is, while not strictly indispensable, a scan tool significantly simplifies the process and ensures all air is purged from your ABS system, maintaining optimal braking performance. Let’s delve into why this is the case and explore your options.
Understanding the Kelsey-Hayes EBC310 ABS System
The ABS system commonly found in these GM trucks is the Kelsey-Hayes EBC310. This system is designed with three channels – one for each front wheel and one for the rear axle. Within each channel, you’ll find both an isolation valve and a dump valve coupled with a low-pressure accumulator. This accumulator is the crux of the issue when it comes to bleeding brakes without a scan tool.
During a standard brake bleed, the low-pressure accumulator remains isolated behind the dump valve. This means that old brake fluid and any trapped air within the accumulator cannot be expelled through conventional bleeding methods. To effectively flush out this section of the ABS, it’s necessary to cycle the ABS valves, and this is where tools like the Actron ABS bleed scan tool come into play.
The Scan Tool Method: Why It’s Recommended
The factory-recommended procedure for bleeding the ABS in these GM trucks involves using a professional-grade scan tool. Tools like the Tech 1 Scan Tool, or more accessible options like certain Actron scan tools equipped with ABS bleed functions, can command the vehicle’s computer to cycle the ABS valves.
By activating the ABS cycle, the scan tool opens the dump valves, allowing the fluid and any trapped air within the accumulators to be pushed out into the brake lines. This ensures a complete bleed of the entire brake system, including the often-overlooked ABS components. Using an Actron ABS bleed scan tool or similar device offers a straightforward and efficient way to guarantee all parts of your brake system are properly bled, leading to a firmer pedal feel and reliable braking performance.
The “Shade-Tree” Method: Risks and Considerations
For those without access to a scan tool, a “shade-tree” mechanic method has emerged. This involves driving the truck on a loose surface like gravel or snow and intentionally applying the brakes hard enough to induce wheel lock-up and activate the ABS. The idea is that cycling the ABS in this manner will also purge air from the accumulators.
However, this method carries significant flaws and potential risks. Firstly, it requires your brakes to be in reasonably good working order to safely drive and perform this procedure. If your brakes are already compromised by air in the system, this could be dangerous. Secondly, when the ABS cycles through this forced method, any air in the accumulators is simply pushed into the brake lines. This could temporarily worsen your braking ability as the air is now circulating within the main brake lines, potentially leading to a spongy pedal and reduced stopping power. After performing this risky maneuver, you would still need to carefully bleed the brakes again to remove the air that has been pushed into the lines.
Actron Scan Tools: Features and Benefits for ABS Bleeding
While the original article refers to the Tech 1 Scan Tool, modern Actron scan tools offer more accessible and user-friendly options for DIY mechanics. Specific Actron models are equipped with features to perform ABS brake bleeding, among other diagnostic and service functions.
Using an Actron ABS bleed scan tool provides several benefits:
- Safety: It’s a controlled and safe method compared to forcing ABS activation while driving.
- Effectiveness: Ensures a complete bleed of the ABS system, including accumulators.
- Efficiency: Streamlines the bleeding process, saving time and effort.
- Diagnostic Capabilities: Actron scan tools often offer additional diagnostic features beyond ABS bleeding, making them a versatile tool for vehicle maintenance.
Conclusion
While it might be technically possible to attempt bleeding the ABS system on older GM trucks without an Actron ABS bleed scan tool by using risky “shade-tree” methods, it is not recommended. Investing in a capable scan tool, such as an Actron ABS bleed scan tool, offers a safer, more effective, and ultimately more professional approach. For optimal braking performance and peace of mind, especially when dealing with the complexities of ABS systems like the Kelsey-Hayes EBC310, utilizing a scan tool to properly cycle and bleed your brakes is the most sensible solution.
Reference:
Brake & Front End Magazine, “Bleeding ABS Systems” by Bill Williams (July 2005). http://www.babcox.com/editorial/bf/bf70518.htm
