The front one this time!! Only just noticed this.. the drivers side wiper on my '85 gradually works its way down to the scuttle, it would seem if you left it on long enough it would end up wiping the bonnet. It is slipping round the spindle in the centre (LHD wipers on an '85!). I have dim memories of this happening to my Jetta of a similar vintage, but don not remember how or even if I fixed it!
take the wiper arm off and look at the splines cut into the spindle. you'll probably find they're all full of metal shavings from the wiper arm, use a thin screwdriver or similar to scrape it all out till splines aree all clear, then look in wiper arm and clean off any loose bits of metal. refit and problem should be solved
