The correct adjustment of the angle of incidence is a mandatory requirement for a faultless wiping operation.
See Test and repair instructions in the WIS: FG 82.30.
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The rubber profile is drawn over the windshield. A low-noise repositioning of the rubber profile after the change in direction is made possible by the change in wiper blade angle relative to the windshield surface in front of the reversal points.
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Negative influencing quantities of the wiper arm on the result of wiping
a) Wiper arm adjustment is outside the specified the specified tolerance range.
b) Mechanical damage to wiper arm.
Clinch bolt loose
Locking lug bent up
Change in spring length, resulting in incorrect contact pressure
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Repair and supporting information:
Check angle of incidence of wiper arm, adjust if necessary.
Replace wiper arm.
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Possible noise complaints about wiper arm
due to different windshield thickness over all model series
Different ambient noises, e.g. vehicle speed, engine
Mounting or vibration damping of wiper system loose relative to the vehicle body, fitted damaged or under stress
Noises caused by the design due to the moved masses (wiper arm and blade) and eddies during wiping mode, flow noises while driving when wiping