2004, Chevrolet, Silverado, LLY
2004.5 Duramax LLY getting a trouble code for open or shorted master cylinder. Spring/Summer blew my brake lines doing 70 on the highway as a driver slammed on their brakes in front of me. Don’t know how I managed it but luckily stopped in the Knick of time. Coasted for 15 miles in traffic “luckily” till I got to my destination to get it towed. Got it fixed with a new set of brake lines and a new master cylinder. Now I’ve been driving around for a while and the light is still on showing the code. Checked the connection and everything looks fine and the truck stops, but every now and then it seams like I lose brake pressure but not enough to leave me with streaks in my pants again. Don’t know if it could be the hydro boost but have changed it myself before around the same time I did the power steering pump with all new steering lines about 7 years or more. The power steering pump is going out the window soon though because I can hear the thing screaming as the truck down shifts after a long highway drive. My fluids are all topped off and no signs of leaks. I usually notice because it’s pretty corrosive and likes to take the very little under coat left off the truck. Any help or similar problem would love an answer!