It might be time to rebuild the vacuum pump. Search the Diesel archives.
Gently pull off one of the hose by the brake booster line - see if you have any vacuum there. If you don't, there is a rebuild kit, and after 1/2 a day, you will be stopping and locking your doors again.

If the vacuum loss is intermittant, it could be a check valve(s) going bad (they are insided the vacuum pump)

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D