The brake lines in 1999-2007 GMT800 Silverado’s, Sierra’s, and Suburbans are very prone to rusting out and needing replacement. For individuals who live in “salt” states, where cities commonly salt the roads to prevent ice, the brake line rusting is even more common. In 2010, a class-action lawsuit was filed as rusted brake lines were leading to brake failure and causing accidents.
This guide is going to discuss why the brake lines fail, what the symptoms are, and what the proper routing is for replacing them. Fortunately we haven’t had this problem yet on our 2002 Suburban, but it’s only a matter of time before we do.
Why the Brake Lines Fail
The brake lines used in all GMT800 trucks are a copper plated steel tube. The lines are then coated with an “AlGal” coating to protect them from corrosion. However, the AlGal coating, which is a form of aluminum paint, was easily damaged or worn down from normal tire kick-up. In 2007, with the GMT900 line, Chevy upgraded the brake line coating to a NyGal coating which was made of plastic and significantly thicker than the previous AlGal coating.
Corrosion can lead to break lines leaking fluid, with the end result being the brakes not working very well, or hardly at all.
Additionally, portions of the GMT800 brake lines are made of rubber. Over time through normal wear and tear, this rubber can get deformed and cause air pockets in the lines when pressed. The end result is not enough brake fluid getting to the calipers for the brakes to function properly.
Brake lines can go bad as early as 50,000 miles, or as late as 250,000 miles. If you live in a salt state, we recommend changing the brake lines approx. every 120,000 miles.
Brake Line Failure Symptoms
- Leaking brake fluid underneath vehicle
- Brake warning light illuminates
- Squeaking brakes
- Shaking, vibrating, or wobbling when braking
- Soft brake pedal, feels spongy
Here is a DIY guide for brake line replacement.
1999-2006 Brake Line Diagram for Silverado, Sierra, Suburban
This brake line routing diagram is applicable for:
1996-2006 Chevy Silverado 1500/2500/3500
1996-2006 GMC Sierra 1500/2500/3500
2002-2006 Cadillac Escalade
2000-2006 Chevy Tahoe 1500
2002-2006 Chevy Avalanche 1500/2500
2000-2006 Chevy Suburban 1500/2500
2000-2006 GMC Yukon 1500/2500