Brake Fluid Reservoir

["Wallin,Bob" <wallinb@domain.elided>]

There is a rubber fitting that fits into the brake fluid reservoir of my 67
Duetto.  It looks somewhat like an accordion bellows, open on one end,
closed on the other.  Question:  What is it for, and two should the open end
be at the top or bottom of the reservoir.  Thanks

R Wallin      Wallinb@domain.elided

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