wiper question

["Evangelos G. Makris" <emakris@hol.gr>]

My car is LHD and has the square wiper motor and two wipers.

The wipers move ok (not lazily at all) but they only go 
from their 9 o'clock (resting) position to the 
12 o'clock one (up to vertical), no further!

So, they leave some important areas on the windscreen unwiped.

Shouldn't they go up to, say, a 2 o'clock position?

What could be the problem here? Brushes? Link? Wheelboxes?

Regards
Evangelos
66 Sprite Mk3