Classic VW Beetles and Campervans

GAP asked: How to replace the brake switch of a VW 1969 Beetle which is on the master cylinder ?Inexpensive web services!

Dog B asked: How do I convert a 61 VW Beetle from single circuit master cylinder to dual circuit? I don’t understand the residual vs non-residual type? Is it a straight up swap of the master cylinder? I am putting in new metal lines and am told that a dual circuit is a good idea?
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