2005 C320 wipers only going up ~2/3 of normal
 

Hi,

I have a 2005 C320 and the wipers are only going from park to about 2/3 normal travel.
I have reset the park position (between the arrows) and all bolts are tight, motor makes complete rotations, but blades only go up about 2/3 or normal travel....

any help is greatly appreciated
Tom