Seven problems related to brake fluid leak have been reported for the 2005 GMC Sierra. The most recently reported issues are listed below.
Went to stop at stop sign, brakes felt spongy. Stopped up the road about 2 miles at my moms house to get my kids, looked under the truck and saw brake fluid dripping down on the left side of the frame behind the left front wheel. I have to replace all of my brake lines now due to rust.
Around the middle of December 2014 the "service brake system" message appeared on my 2005 GMC 1500 Sierra sle. I checked the brake fluid reservoir and it was nearly empty. I could not find where the fluid had leaked from so I serviced the reservoir with 12 ounces brake fluid to the full mark. From about December 15, 2014 until 28 December 2014, I lost about 7 ounces of brake fluid. No trace of brake fluid can be found on the driveway. I crawled under the truck and had my wife press the brakes while I looked for a leak. I found the leak near the left rear wheel area on a very corroded bracket. It appears to be a very small hole because the fluid comes out as a fine mist and not a stream. The rigid brake line connects to a flexible brake line at the bracket and there is a lot of rust at the connection as well as the brake line. I have found rust forming on other brake lines as well.
2005 GMC Sierra z71. I am the original owner. This vehicle has 18k miles, yes 18 thousand original miles. This truck does not get beat on at all, no off road etc, and it has been well taken care of since new. There is a rust issue with these trucks. On 5-19-2014, on my way to the car wash my brakes started to feel very soft and the truck was not stopping. I changed routes to my mechanics shop, and while en route lost the rear brakes. I thankfully arrived (driving very slowly) to the front of his shop. I got out and saw a puddle of brake fluid leaking out of the rear end brake lines rear lines were completely rusted. He inspected the vehicle, and as if this wasn't enough, informed that the transmission lines were also leaking (rusted). Mechanic added that I should be prepared for the fuel lines to rust through next. This line replacement job will cost me about 2k. Not to mention the issue with the lower rockers and cab corners rusting. That estimated is for another 2k. I purchased this truck to last me, and apparently gm does not build a quality product anymore. There a numerous complaints about this issue, and gm refuses to acknowledge the problem. Very unhappy!.
I was stopped at a traffic light with my foot on the brake pedal when suddenly the pedal went almost completely to the floor. After getting safely off the roadway, I inspected the truck and saw a lot of fluid leaking from beneath the rear of the cargo bed. I then discovered that a rear brake line had ruptured, apparently from corrosion. I checked the brake reservoir and found that it was almost empty. Once I got the truck to a repair shop I saw that all the tubular brake lines were severely corroded and all needed to be replaced. I had stainless steel lines installed and repair costs exceeded $1. 200. 00. I've owned this truck since it was brand new and have always kept it very well maintained.
Began to back out of parking space when the brake pedal fell flat to the floor. Lost all braking power and was unable to stop. Brake fluid leaking from rusted line.
The contact owns a 2005 GMC Sierra denali. The contact stated that while driving 50 mph and depressing the brakes, the pedal became spongy. The contact inspected the brakes and noticed that the hydraulic brake line was severely rusted and corroded. The brake line was also fractured and caused brake fluid to leak. The vehicle was not taken to the dealer. The manufacturer was notified of the failure, who recommended that the contact take the vehicle to the dealer for inspection of the failure. The vehicle was not repaired. The failure mileage was 49,800.
Vehicle was driven on a driveway and the brake pedal lost complete resistance and went flat to the floor. Total brake failure occurred without any warning indicators. Inspection of the metal brake lines positioned near the left front wheel revealed that all four lines showed severe signs of corrosion and one of the lines had produced a hole therefore leaking brake fluid.