How to reverse the wiper blades on your 993

This DIY is contributed by Aaron Schreder (A.J.)

I recently completed the windshield wiper reversal project on my '95 993 as mentioned on this board last month, and wanted to pass along the info. The wipers now rest in front of the passenger instead of the driver. The directions that I followed were only text, and unfortunately, I still haven't broken down and bought a digital camera, so I don't have illustrations, either. First of all, many thanks to the author of the original DIY about switching the park position of the wipers. It was a big help, and without it, I would not have attempted it. This DIY could be considered further development of that DIY. The original DIY suggested that this project would be good to do when replacing the pollen filters, because a lot of common items would be removed. I was also under the impression that I needed to remove the screen at the back of the hood, and remove the ductwork underneath. I also removed the LH side pollen filter and cover, and spent a good amount of time removing all this. Once it was all off, I noticed that the wiper motor output shaft was all the way over to the left side, and none of this stuff had to be removed. So let me start at the top, and be as brief (but thorough) as possible:

First of all, this is NOT an easy project. It's quite simple in theory, but VERY difficult in execution. If you have large hands or you hands aren't very nimble, forget it. I probably spent five hours on this project, but I hope to save others from wasting the same time I did.


Phillips screwdriver 
flat head screwdriver 
10mm 12pt wrench 
2' of string 
flexible magnetic pick tool


-  Remove the carpet from the trunk, remove the plastic cowl cover and rubber seal that runs across the back of the trunk. 

The wiper motor is on the left side, tucked up under the cowl, and is impossible to see without leaning over and all but sticking your head into the trunk. The output shaft is canted forward and outboard a little. The output linkage is about 2" long coming off it. The idea is to loosen (remove, because it's splined) the nut on the output shaft, rotate the output linkage 180 degrees, and retighten the bolt. The area is so tight, I could barely get my fingers in far enough to actually touch the shaft, and doing so caused bruises for later.

-  Under the cowl cover that you first removed there is a black plastic, half round shroud in front of the wiper motor. This is the left side pollen filter housing. I removed it just to be sure, but it may be necessary. Loosen the finger nut on the inboard side of the pollen filter housing. On the outboard side, there is a silver latch. Push on the middle of it and the end will extend, allowing you to remove it. The housing comes straight off. The filter also comes straight off. Note the locator tab on the top of the filter. It's a notch that needs to be straight up when reinstalling. If it's not, you may spend 20 min wondering why it doesn't fit... There are two metal air conditioner tubes running behind the pollen filter housing. I very carefully pulled them forward out of the way, because the wiper motor is behind them, and I needed all the room I could get.

-  I have a flexible magnetic "picker" that I got from Griot's Garage (from my wife for Christmas) that made this DIY possible. Without it, I
don't think I would have been able to do it. There is a plunger on one end, and the magnet extends out of the plastic housing only when the plunger is depressed. So it can be located precisely without sticking to all metal objects in the vicinity, and objects can also be released and picked back up. The nut on the wiper motor shaft is 10mm, and I could barely even get the wrench in far enough to engage the nut. Using my right hand, I got the wrench close. Using my left hand, I fine tuned the position of the wrench with the magnet picker. Once the wrench was on the nut, it was very difficult to break the nut loose since there was very little room to maneuver. And the wrench had to be repositioned each time. There was not enough room to use a 6pt wrench. A ratchet would have been nice, but there was barely enough clearance to get the wrench over the nut because the output link above the nut interfered with anything larger. For better clearance, I cycled the wiper half way across the windshield and turned off the power. That opened up the linkage a little better. NOTE: I tied a string to my wrench because I knew I was going to drop it at least once every time I tried to reposition it on the nut. 

-  Factory position, the output link points to the right from the motor shaft. For the wipers to park in front of the passenger, the link needs to
rotate 180 degrees, pointing to the left. The problem is, the linkage covers up the nut in this position. I couldn't even SEE the nut, let alone
kid myself into thinking I could get a wrench on it. Using intermittent wipe, I cut the power when the wipers were vertical on the glass. To remove
the linkage from the wiper motor shaft, I used the flat head screwdriver as a wedge, and let out a little frustration. I advanced the linkage 180
degrees from that position (clockwise, arbitrarily), retightened and tested. This gives the best access to the nut in both positions. I wish I would
have done it this way the first time... 

-  On a single stroke, if the wiper cycle ends smoothly, but starts with a jerk down, then proceeds up and across the glass, you have not
advanced the output link on the motor shaft enough. The link needs to be advanced clockwise on the shaft, making sure the shaft is not turning with it. If on a single stroke, the wiper comes down on the return stroke, hesitates and jumps back upwards before stopping, you've gone too far. The link needs to be turned counter clockwise.

The DIY I was working from talked about switching the wiper arms and bending one of them to fit the glass. I don't understand why this would be done.  The wipe pattern is optimized for LH drive. And as always, if I don't bend the wiper arms, it's easier to go back to the factory position if I ever need to. I adjusted the park height on the right side down a bit, since I had them down as low as possible when they parked on the left. No other problems, and now that I've forgotten about blowing an entire evening and the cuts and bruises on my hands have healed, I can say it was all very worth it!!
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