This service bulletin came out in April of 1987 but applies to all 1984 - 1996 Corvettes and is a valuable source of information on the care and service of your C4 Corvette's windshield wiper system.
Subject: Windshield Wipers Chatter and/or Wipe Unevenly
Model and Year: Domestically Produced Passenger Cars
Source: Chevrolet Dealer Service Bulletin
Bulletin No: 87-104
Date: April, 1987
TO: ALL CHEVROLET DEALERS
Some vehicles may exhibit a condition where the windshield wipers chatter and/or wipe unevenly. Several items may contribute to this condition. To completely repair this condition, all applicable items covered in this bulletin should be checked and repaired as necessary.
Clean Windshield Glass
Clean windshield glass with GM glass cleaner, Bon Ami (Trademark), or equivalent. The cleaner used should be one which will not harm paint finish or scratch glass. The glass is cleaned when water no longer "beads up", but "sheets" across the entire glass surface.
Clean Wiper Blade Elements
Remove wiper blade assembly from wiper blade arms. Clean Rubber elements with a cloth which has been saturated in a solution of 50% water and 50% GM Opti Kleen, or a solution of 50% water and 50% methyl alcohol. Rinse blade assemblies with water and reinstall on wiper arms.
Check Fit of Windshield Reveal Molding (Figure 1)
On vehicles equipped with depressed park (hidden) wiper blades and windshield lower reveal molding, check the fit of the reveal molding across the base of the windshield. The lower reveal molding must fit uniformly along the glass surface to allow the wiper blades to move freely from the glass wiper area to the park position when the wipers are turned off. Gaps in excess of 1.0mm (.040 in.) should be corrected using the following procedure.
Check Windshield Wiper Arm Pressure (Figure 2)
|All domestically produced
passenger cars except Cavalier
|29 +/- 3|
|Cavalier||24 +/- 3|
Check Wiper Blade Mounting Angle (Figure 3)
With the right hand wiper arm assembly in the middle of a wipestroke and the wiper blade assemblies removed, visually check that the blade assembly mounting pin on each wiper arm is parallel to the windshield. Replace the wiper arm if necessary.
Check For Blade Set (Figure 4)
Remove the wiper blade assemblies from the wiper arms being careful to note orientation for reassembly. Look down the length of the blade element. The rubber element which contacts the glass must be on the center line of the blade assembly +/- 15 degrees. Replace the element if necessary.
Check Wiper Arm & Park Position Adjustments (Figure 5 & 6)
When the wipers are shut off after operation on wet glass, both wiper arm and blade assembly should be fully seated on the park ramps. In the full left stroke position, the tip of the blade element must be no more than 78mm (3 1/16 inches) from the pillar. if wipers require adjustment, refer to section 8E of the appropriate Service Manual.
Chevrolet Motor Division
General Motors Corporation
Article ID: 1089
Created On: Sat, Jan 10, 2015 at 9:34 AM
Last Updated On: Sat, Jan 10, 2015 at 9:34 AM
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