• 2021

Wiped Out

WINDSHIELD WIPER BASICS AND SERVICING

Everyone is familiar with the operation of windshield wipers. The wiper blades, attached to the wiper arms, move back and forth across the windshield and remove rainwater, snow and any other foreign substance, such as dust or dirt, from the windshield.

Figure 1

Figure 1

A typical windshield wiper assembly is shown in Figure 1. The windshield wiper arms are designed to mechanically transmit the motion from the wiper pivots ① to the wiper blades. The wiper motor crank arm (not visible) is a stamped steel unit that is secured to the wiper motor output shaft. Two stamped steel drive links ② connect the wiper motor crank arm to the two wiper pivot lever arms. The wiper motor ③ is secured by a bracket integral to the motor transmission housing.

The wiper arm must be properly indexed to the wiper pivot in order to maintain the proper wiper blade travel on the glass. This is accomplished with a tapered mounting hole in the wiper arm end that interlocks with the serrations on the tapered outer circumference of the wiper pivot shaft. Mounting nuts lock the wiper arms to the threaded studs on the wiper pivot shafts.

The wiper blades move back and forth across the glass by the wiper arms when the wipers are operating. The wiper blade superstructure is the flexible frame that grips the wiper blade element and evenly distributes the force of the spring-loaded wiper arm along the length of the element. The combination of the wiper arm force and the flexibility of the superstructure makes the element conform to and maintain proper contact with the glass, even as the blade is moved over the curvature across the glass surface.

Several vehicles, such as the minivans and the Jeep® Cherokee and Grand Cherokee, have rear windshield wiper systems for the liftgate glass. The rear wiper motor is concealed within the liftgate, below the liftgate glass opening and behind the liftgate inner trim panel. The end of the motor output shaft extends through the liftgate outer panel and the liftgate glass. This output shaft drives the rear wiper arm and blade is the only visible component of the rear wiper motor. The rear wiper motor transmission converts the rotary output of the wiper motor to the back and forth wiping motion of the rear wiper arm and wiper blade.

WINDSHIELD WIPER PROBLEMS

When someone first mentions windshield wiper problems, the first thing that probably comes to mind is worn out wiper blades. Usually, the conditions such as smearing and streaking are cause to inspect the wiper blades, but wiper blades and wiper arms should be inspected periodically.

Refer to Figure 2. Look for the following signs of damage and deterioration when inspecting wiper blades: ① worn or uneven edges, ② deposits of foreign material, ③ hardening or cracking of the blade material, ④ deformation or fatigue, ⑤ splitting of the blade and ⑥ damage to the wiper arm itself.

Figure 2

Figure 2

To inspect the wiper blade, carefully lift it off the glass. Note the action of the wiper arm hinge. The wiper arm should pivot freely at the hinge, but with no lateral looseness. If there is any binding in the hinge, or evidence of lateral play, replace the wiper arm. Also check for wiper arm hinge for proper spring tension. The spring tension is sufficient if the wiper blade conforms to the curvature of the windshield. If not, replace the wiper arm.

It is important to protect the rubber squeegees of the wiper blades from any petroleum-based cleaners, solvents and contaminants. These products can rapidly deteriorate the rubber squeegees. The squeegees exposed to the elements for a long time tend to lose their wiping effectiveness. Periodic cleaning is suggested in order to remove deposits of salt, wax or road film. The wiper blades, arms and windshield glass should only be cleaned with a sponge or soft cloth and windshield washer fluid, a mild detergent or a non-abrasive cleaner.

After cleaning and inspecting the wiper components and the glass, if the wiper blade still fails to clean the glass without smearing, streaking or chattering, replace the wiper blade(s).

In those parts of the country that experience heavy snowfalls, continually wiping snow off the windshield can lead to the wiper arm loosening. If this occurs, tighten the nut that secures the wiper arm to the wiper pivot shaft.

SERVICING WINDSHIELD WIPERS

Replacing wiper blades is the most common service procedure for windshield wipers. There are several different styles of wiper arms, but one of the common types is the hook design used on the Challenger/Charger/300. Refer to Figure 3. Remove the wiper blade in the following manner:

Figure 3

Figure 3

Lift the wiper arm ② to raise the wiper blade and element ⑥ from the glass, until the wiper arm hinge is in its over-center position. To remove the blade from the arm, depress the latch release tab ④ on the pivot block ③ under the tip of the arm and slide the blade away from the tip towards the pivot end of the arm far enough to disengage the pivot block from the hook formation ⑤ on the end of the arm. Extract the hook formation on the tip of the wiper arm through the opening in the wiper blade superstructure ⑥ just ahead of the pivot block.

Gently lower the tip of the wiper arm onto the glass.

Install the new wiper blade in the following manner: Lift the wiper arm ② from the windshield glass until the wiper arm hinge is in its over-center position. Position the wiper blade near the hook formation ⑤ on the tip of the arm with the notched end of the wiper element flexor oriented towards the end of the wiper arm that is nearest to the wiper pivot. Insert the hook formation on the tip of the arm through the opening in the blade superstructure ① ahead of the pivot block ③ far enough to engage the pivot block into the hook. Slide the pivot block up into the hook formation on the tip of the wiper arm until the latch release tab ④ snaps into its locked position. Latch engagement will be accompanied by an audible click. Gently lower the wiper blade and element ⑥ onto the glass.

Figure 4

Figure 4

Several FCA US LLC models, such as the Journey/Compass/Cherokee and the minivans, have rear windshield wipers. Replacing the blade is not any different than it is for the front wiper blades, but there is a glitch on some rear wipers. In order to raise the wiper blade off the glass, a plastic tab, that covers the wiper arm mounting nut, must be pulled up (see Figure 4). If it is not lifted, the wiper arm only comes off the glass about an inch and blade replacement is impossible.

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