- Remove the wiper blades from the wiper arms. Refer to 
Windshield Wiper Blade Replacement
 .
 
- Look down the length of the blade element.
 
- Replace the wiper blade element if the rubber element which contacts the glass is deflected more than 15 degrees from the centerline of the blade. 
 
- Install the wiper blades on the wiper arms. Refer to 
Windshield Wiper Blade Replacement
 .