For maximum effectiveness and longest element life, the windshield and wiper blades should be kept clean. Dirt, tree sap, road tar and so on will cause streaking, smearing and blade deterioration if left on the windshield. It is advisable to wash the windshield carefully with a commercial glass cleaner at least once a month. Wipe off the rubber blades with a wet rag afterwards. Do NOT attempt to move the wipers back and forth by hand; damage to the motor and drive mechanism will result.
If the blades are found to be cracked, broken or torn, they should be replaced immediately. Replacement intervals will vary with usage, although ozone deterioration usually limits blade lift to about one year. If the wiper pattern is smeared or streaked, or if the blade chatters across the glass, the blades should be replaced. It is easiest and most sensible to replace them in pairs.
There are basically three different types of wiper blade refills, which differ in their method of replacement. One type has two release buttons, approximately 1 / 3 of the way up from the ends of the blade frame. Pushing the buttons down releases a lock and allows the rubber blade to be removed from the frame. The new blade slides back into the frame and locks in place.
The second type of refill has two metal tabs which are unlocked by squeezing them together. The rubber blade can then be withdrawn from the frame jaws. A new one is installed by inserting it into the front frame jaws and sliding it rearward to engage the remaining frame jaws. There are usually four jaws, be certain when installing that the refill is engaged in all of them. At the end of its travel, the tabs will lock into place on the front jaws of the wiper blade frame.
The third type is a refill made from polycarbonate. The refill has a simple locking device at one end which flexes downward out of the groove into which the jaws of the holder fit, allowing easy release. By sliding the new refill through all the jaws and pushing through the slight resistance when it reaches the end of its travel, the refill will lock into position. Regardless of the type of refill used, make sure that all of the frame jaws are engaged as the refill is pushed into place and locked. The metal blade holder and frame will scratch the glass if allowed to touch it.
To replace the original factory-equipped wiper blades, pull the top end of the rubber inward until the rubber blade is free of the end slot and the replacement hole is visible. Pull the rubber blade out of the replacement hole. Insert the end new rubber wiper blade with the protrusions into the replacement hole and work the rubber along the slot in the blade frame. Once all the rubber is in the frame slot, allow it to expand and fill in the end. Check the wipers for proper operation.