Such as hardening of the wiper blades should be replaced. Feel good use the wipers in the rain was heavy, but the moment when the rain start wiper blade will find the wipers wipe uneven traces left on the glass surface affect your vision, suggesting that the wiper has hardened.
Check wiper blade pull up with your fingers after cleaning the wiper rubber touch, check for damage and how flexible rubber blades. If the leaf aging, hardening, cracks, wiper blades need to be replaced.
When the wiper blade arm spring tension becomes weak, the need to replace the wiper arm. Wiper blades with the forces in close contact with the windshield wiper arm spring.
The spring tension becomes weak due to high speed to bring strong pressure leaving the wipers windshield float, this is more prominent in the long dimension of the wipers on, resulting in part of the glass is not scratch to sweep.