1. Preparation:
* Park the car: On a level surface, engage the parking brake.
* Disconnect the battery: This prevents accidental activation of the wipers.
* Gather tools: You'll need a wiper arm puller (highly recommended to avoid damage), a socket wrench (likely a 10mm or 13mm, but check your owner's manual or consult online resources for your specific model), and possibly some penetrating oil (like PB Blaster).
2. Remove the wiper arm:
* Locate the wiper arm nut: It's usually hidden beneath a plastic cap or cover on the wiper arm base. Remove the cap if necessary.
* Spray penetrating oil: Apply penetrating oil to the nut to help loosen it. Allow it to sit for a few minutes.
* Use the wiper arm puller: This tool makes removing the arm significantly easier and safer. Clamp the puller onto the arm and carefully turn the puller's screw to separate the arm from the wiper spindle. If you don't have a puller, you may be able to gently pry the arm loose with a flat-head screwdriver, but this risks scratching the wiper spindle or breaking the arm. If you must use a flathead screwdriver, place it between the arm and the spindle, then pull/pry up while gently twisting.
* Remove the nut: Once the arm is free, unscrew and remove the nut.
3. Address the Misalignment:
* Inspect the linkage: Carefully examine the wiper transmission linkage for any damage, bending, or looseness. If the linkage is bent or damaged, you'll need to replace it.
* Realign the arm (if linkage is fine): If the linkage seems fine, simply reattach the wiper arm. Make sure it's properly seated on the wiper spindle.
* Tighten the nut: Secure the nut firmly to the spindle.
4. Reinstallation and Testing:
* Reattach the wiper arm: Carefully align the arm with the spindle and tighten the nut.
* Reconnect the battery:
* Test the wipers: Operate the wipers to ensure proper function and alignment.
Important Considerations:
* Wiper Spindle: The wiper spindle itself might be damaged or worn, leading to misalignment even with a correctly installed arm. If you've replaced the arm and linkage and still have misalignment, this could be the problem. This usually requires replacement of the entire wiper transmission assembly.
* Owner's Manual: Consult your 1999 Pontiac Grand Prix's owner's manual. It might have diagrams and specifications for your specific model.
* Professional Help: If you're uncomfortable performing this repair yourself, take your car to a qualified mechanic. Improperly installing the wiper arm could lead to damage.
Remember safety first. If you're not comfortable working on your car, it's always best to consult a professional mechanic. They have the tools and experience to do the job correctly and safely.
