Ya know that feeling you get when you realize something ya should have noticed long ago... I just noticed today after we pulled the engine from a HMMWV, looking at the disc brake lines. They are ALL hard lines! Keep in mind the differential is bolted to the frame and the brakes a mounted inboard, at the diff. I just assumed that there would be a flexible line attaching to the caliper, especially 'cause the calipers (front & rear) are FLOATING. All the flex is done by a small "pigtail" in the tubing just before the caliper. Checked the parts manual and all the versions use this method, until the most recent A2 variants (which do utilize a short brake hose). I don't think there was any safety issue involved in the change, the Army gets pretty wound-up with safety modifcations and such. I guess those with rear disc brake conversions that wanted to run a hard line to the caliper really wouldn't have much of a safety concern after all. I should have known this before 'cause I have pulled the calipers off at one time or another. At the time it just didn't seem that important.. Real trucks don't have spark plugs!