Had this same problem on a VW Bus recently.  It was the brake booster.
There is a spring inside that which allows the pedal to return.  We have
them available on our site at www.vanagain.com if you need one.

Ken

On Wed, May 17, 2017, 2:22 AM J.C. <dougm+sfbayrangers@kzsu.stanford.edu>
wrote:

> Question for the list, that I haven't found a definitive answer for:
> My girlfriend's 85 Westy has an issue wherein the brake pedal isn't
> retracting into the resting position. Thus, the brakes are dragging
> (and the temporary solution has been to use one's foot to retract the
> pedal while driving.) The brakes themselves don't feel mushy/soft,
> thus it doesn't seem to be a master cylinder issue, or air in the
> lines.
>
> My 1st thought was that there was an issue with the spring, but (as
> well as I could tell) it doesn't appear to be broken, and it does
> appear to be attached.
>
> Does anyone have an idea as to how to diagnose and repair?
>
> (Searched the 1st 8 pages of results from a search of the archives but
> couldn't find anything.)
>
> Thanks.
>