The front passenger wiper has an annoying knocking noise as though its catching the A pillar or base of the windscreen (which it isn't!)

 

I've tried bending the wiper arm by hand a bit and for some reason its better on the shortest interval intermittent rather than normal wipers on.

 

Any ideas ??

 

(They are almost new Bosch Aerotwins - correct size, and I've already Autoglym glass polished the windscreen and wiper rubbers themselves.

Odd problem, could be a number of things :-

 

Excessive play in the wiper linkage / motor mounting points working loose / arm splines worn / gear teeth worn on motor  (not very likely).

The strange thing is thats its not a consistant problem.