So, got an 99 1500, and my brake fluid is going somewhere that I don't know. Crawled under the truck and traced the break lines looking for leaks but found no evidence. Look through the threads and some say look at the fire wall, well no signs there either, so I can't figure out where it is going. The brakes are soft and have to be pumped to stop. So any clues?

 

Probably the line that goes over the gas tank. (rear brakes) They are notorious for that. Won't always be obvious until the line blows completely. Have someone else pump the brakes while you look/listen underneath for evidence. Shouldn't be too hard to find.

 

If the brakes are soft, there is air in the system.

Check again for leaks. Pull the drums off the rear and look at the wheel cylinders. They could be leaking. Another common place is the brake line next to the fuel tank.

I've also heard of mysterious fluid loss that ended up being the master cylinder was leaking into the booster. Therefore, no visible leak.

 

brake lines are usually fast leaks that are easy to find.
rear wheel cylinders are usually slow leaks that ooze out and sort of loses itself in dust and dirt.

 

When my '98 started using brake fluid without an obvious leak, it was the master cylinder seal leaking into the booster.