I have not done this on a W123 but on a W108 it's not that big a deal to remove the line. Your best bet would be to find a good used line at a Pick & Pull. Forget the rubber line option that's asking for trouble. You might be able to splice the line together using compression fittings but I'm not sure the ones at Home Despot would fit a metric line. The last option would be to take the line to a hydraulic shop and see if they can repair it.

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Bill Reimels
Now down to one:
1972 300SE 3.5 W109 (Euro delivery)