Need help with wiper repair

My windshield wipers on my '88 Grand Wagon are broken and my efforts to fix them have failed thus far. The car needs inspected, but more importantly I can't drive it when they are calling for rain. Under the dash in a very tight spot there is a place where the motor linkage connects to the blade linkage. There is a pin on one arm that fits through a plastic washer that is pressed into the second arm. After placing the pin through this washer, there is a clip that pushed over the pin, (which has a nub on the end), so when the clip is pushed over this the nub keeps it from coming back off. The hole in the original metal clip over the years has worn so it won't hold in place anymore. I've been to the dealer etc and no one even shows the clip as a part for sale. I've tried to find interior trim clips to fit. The problem is that you have to really push hard on the clips to clear the nub because it doesn't go past the washer by much. That much backward pressure causes the clip not to hold for very long before it pops off. The original metal clip fit on one of the arms and slid along it's length. The hole was u-shaped and went all the way to the end of the clip, so you basically slid it down the arm and over the pin. I thought I had it licked when I decided to loop a cable tie around the pin and tighten it down as far as I could. This works for awhile, but eventually the cable tie pops off too. I hope I'm giving a picture that someone who may be able to help me can understand. I need something about the diameter of a nickel, the thickness of a dime, that I can somehow slip over a pin, and then tighten it or fasten it so it holds, but still allows the arms to freely rotate. I am hoping someone out there had the same problem and found a solution.