Diesel line leaks- why?

[Richard Eldridge]

My 300 D sedan began to run rough and I noticed that fuel was squirting from the #4 fuel line, the prebent metal tube that carries fuel from (I assume) the Diesel pump to the injector. I tried tightening it, with no results, so I removed it.

It was VERY tight, by the way.

There is a tapered tip on both ends and a fairly thick washer on each end and a fitting that screws down and pushes the tapered tip into the Diesel pump fitting on one end and the injector atop the motor on the other end.

There is no sign of why this might be leaking: the end that does not leak looks exactly like the end that does: there is no break, hole, rough place or other sign of why this thing might be leaking.

As yet there it was, merrily squirting little droplets of Diesel all over the place.

The last work done on this engine was a replacement of the flexible return lines, which I had done at a shop, where the mechanic had replaced the crush washer on the #5 cylinder. None of these repairs would require any touching of the fuel lines, which are below the turbo.

I am supposing that the problem can be solved by replacing the fuel line. They are ordering this and I should have it tomorrow.

I cannot figure out how Diesel fuel under pressure could cause a leak in these metal fittings.

Previously, the #1 line was broken off at the tip where it enters the Diesel pump, and I replaced it. I have no clue as what could have broken this, either.