About four days ago, I noticed that the brake pedal seemed to sink while holding at a stop. The next day my wife drove the truck. After she got home, there was a puddle under the front left. At first, I thought one of the hoses off of the steering box finally busted. Checked the level, it was good. Looked around, and noticed fluid dripping in the right rear wheel well. Looked on the other side and found the brake proportioning valve. I do not see any leaks. So, I started the engine and began pumping the brakes, then held it as if I was at a stop. The pedal sunk...I then turned off the engine. There was a puddle and was traced back to the valve. I looked over and found the leak coming from the diaphragm...

I am just glad the valve didn't burst at the wrong time....

I should have the replacement in later today (Saturday). I plan to install it as soon as it comes in.....