Don't do what I did with the injector return hose task today. I decided to pull off the one line that looked the worst. Sure enough, it was rather brittle, and broke rather than sliding off the injector. No problem, just a little more work to get the piece off.
Well, I'm great for doing maintenance on my vehicles in stages, since it helps to get away from the job and think about it. So, I didn't put on the new hose right away.
Whew! Thankfully I had another reason to go back into the garage. Diesel fuel on the floor! Maybe only a few tablespoons, but it sure was a mess. I think there was some kind of siphoning action going on.
Two hoses were brittle, two were in good shape, and the little end piece with the plug was brittle. Appeared to be the brittle ones that were leaking.
Moral of the story: Once you tear the old hose out, put the new stuff on right away!