I just changed out my '64 2 dr to stainless line on the rear. I had replaced it with rubber 22 yrs ago, but as I was trying to bleed the system after adding disc up front I found a lack of fluid in the rear. Don't know how long it has been bad? It stopped "okay"(for 4 wh drum). The new nylon/stainless lines are nice. Make sure to get "DOT" rated lines. They typically have black vinyl coating over the stainless braiding.