Brake Master Cylinder problems of the 2000 GMC Sierra 1500

During a normal stop at a stop sign on a rural road, a steel brake line ruptured due to excess corrosion. This one line between the master cylinder and abs module is the only line that provides pressure to the front brakes, which supply roughly 75% of the vehicle's braking power. The rupture resulted in rapid fluid loss and therefore a lack of pressure in the hydraulic system to allow for adequate braking. Needed to swerve into a ditch to avoid a crash with cross traffic. Visual inspection indicates most brake lines are extremely corroded, and were obviously made with substandard materials as compared to other manufacturers. I do recognize that this is an old vehicle, however other vehicles of similar age and driven in similar environments do not have this issue. Online research, most notably the complaints filed to NHTSA, indicate this is a common problem with chevy/GMC trucks of this era. Although other oem's (Subaru) have issued recalls in similar situations, it appears that the gm that the public bailed out just a few years ago has decided to deny that this is a problem, gambling that the the cost of lawsuits associated with deaths do not exceed the cost of a recall.

21 year old step-daughter drove my truck to work this afternoon, when she went to leave at the end of her shift, she stepped on the brake pedal to shift out of park, it went all the way to the floor. Thankfully she was still in her parking space, and not out in traffic on a very busy 6 lane road. I found at least one of the 2 brake lines from the master cylinder rusted completely through where they are clipped into the plastic guide on top of the frame.

1st incident on or about November 2010 rear brake line failure no previous warning light indication - steel line burst causing brake failure along with emergency brake failed this happened at about 10 miles an hour so the vehicle was able to be stopped by a curb. Testing the brakes none worked even though it was a rear line failure. Vehicle towed and repaired by replacing the line from absbox to rear and the emergency brake shoes and rear disc pads were also replaced. Even with the emergency brake shoe replacement its ability to stop the truck was minimal at best 2nd incident on or about August 2011 the truck failed to pass nc state safety inspection as emergency brake would not hold - the emergency brake shoes and rear disc pads were replaced again with similar results with the previous replacement - with marginal emergency braking operation, but enough to pass the nc state inspection - also the backing plates of the rear brakes had to be replaced as they had rusted away 3rd incident on or about October 2011 front brake failure no previous warning light indication - steel line to front brakes burst where two of the lines were rubbing together where they cross over the frame from the abs box. This occurred at a stop sign. The hydraulic system maintained some stopping ability and that combined with the recently replaced emergency brake pads did stop the truck just slightly past the stop sign. To move the vehicle to a safe location it had no hydraulic stopping ability, but the emergency brake did function marginally at the very slow speed. The vehicle again needed to be towed. Due to the way the front four steel lines are run and bundled together with obvious other points where these lines rub together combined with rust will require all the front steel lines to be replaced including the steel lines from the master cylinder too the abs box.

Contact states: when he has a load on this truck the brakes feel like they are failing. When he applies the brakes, they go to the floor. Dealer replaced the master cylinder, but it didn't fix the problem. Sometimes when sitting still and just idling caller can press on the brakes and they will go to the floor. General motors says this is a normal occurrence.