Checking and servicing them. If car wipers smear and the squeegees are more than 6 months old, it’s time to replace them. On most cars, you release the old ones by squeezing the tangs of a clip at one end or by pressing a button near the blade’s end. Slip a new squeegee into the blade links; it should snap into place.
Replacing a blade
If a blade is bent, damaged, or corroded, replace it. Most have obvious slide locks, levers, or catches: some have a post that you disengage from a hole. On a side-pin type, use a narrow screwdriver to push down on a coil spring while simultaneously prying between the ann and the blade with a second screwdriver.
If a blade chatters, the blade or squeegee is frozen, or the arm may be bent. Turn off the wipers with the blade at midstroke; check whether the blade and squeegee are flat on the glass.
Straighten a bent arm by gripping it with two pairs of pliers held several inches apart and twisting the arm. If this fails, replace the arm.