I've used Oberon's stop-leak years ago for my M.Benz W126..... Well, it seems that it works quite well. There was no leak even up to now, and I've never overhauled the steering box.
That will only help for a short time period. What it does is to expend the rubber of the seal to stop the leak. But the rubber afterwards will break easily. Once the seal was broken, you are back to ground 0.
