To the best of my ability to interpret your post...it sounds like you have two double acting hydraulic cylinders on your bucket and have a broken fitting on one of the cylinders? If that's the case then, no, you cannot join the two lines with another line. Since both cylinders feed lines are T'ed together all that will do is allow all oil to bypass the one good cylinder and it would go where gravity pulled it. You would have to block both lines that feed the cylinder with the broken fitting so that the other cylinder will operate correctly.
Thanks... Perfect answer... -and it all fell into place...