Why do it? Cause the cars are old and stuff doesn't last forever.
When to do it? When you are replacing the clutch master and slave cylinders cause one or both failed.
Go to auto parts store, junk yard, parking lot (watch out for owner) and get a front brake hose from a 280ZX. Side and year doesn't matter, they are all the same. To be less confusing, ask for the driver's side front brake hose for a 1982 280ZX. Probably be a good time to buy some more brake fluid as you will have to bleed the system when you are done.
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