I found an 11 inch wiper arm mostly used on Jeep CJ vehicles up to the mid 80s that fit the adjustable arm and worked well on the windshield. From there I could determine the sweep I wanted it to have. Once I figured that out I could measure the length of the arm and do some math to determine the sweep angle, which in my case was 89.2 degrees.
The inside arm of the pivot would also need to move through this angle. Using some more trig I determined that they needed to move 1.4 inches to get that angle. The motor has an arm that rotates 360 degrees to make one sweep of the wipers. That arm needs to be 1/2 of the length of the sweep (0.7") since a full rotation will turn through a full 1.4".
Of course my first attemp at building the sweep arm I forgot about the 1/2. So I built it to be 1.4" long, the shorter length proved harder to do. It should work but it could have been cleaner. Worse case I may have to find another arm and start again as the motor side mounts using a tapered splined hole that I couldn't re-create.
I cut the stock pivot mount off the arm and welded up some 3/16" bar stock to get the needed length. That was drilled to accept a piece of round stock the same size as the rod ends which was welded into the hole. I cut a groove in the rod to hold an e-clip to retain the rod ends. I should have tried to increase the offset of the arm slightly to prevent any interference with the nut and the rod ends, but a washer acts as a spacer and does the same thing.
My second mistake was that I had mounted both pivots into the cab the same way, with the interior arm pointed downward. After looking at the sweep I decided I wanted the park position and sweep direction to be opposite each other. They will park against the outside of the window and move toward each other in the center. That meant that one side needed to be a mirror image of the other. So I had to remove one of the pivots, file a new mounting tab on the opposite side of the hole so it could be mounted with the pivot arm pointing upward. Not a huge issue since the washer hides the other slot but not perfect. I could try and weld it closed but that will probably cause more trouble then it solves.
The inside arm of the pivot would also need to move through this angle. Using some more trig I determined that they needed to move 1.4 inches to get that angle. The motor has an arm that rotates 360 degrees to make one sweep of the wipers. That arm needs to be 1/2 of the length of the sweep (0.7") since a full rotation will turn through a full 1.4".
Of course my first attemp at building the sweep arm I forgot about the 1/2. So I built it to be 1.4" long, the shorter length proved harder to do. It should work but it could have been cleaner. Worse case I may have to find another arm and start again as the motor side mounts using a tapered splined hole that I couldn't re-create.
I cut the stock pivot mount off the arm and welded up some 3/16" bar stock to get the needed length. That was drilled to accept a piece of round stock the same size as the rod ends which was welded into the hole. I cut a groove in the rod to hold an e-clip to retain the rod ends. I should have tried to increase the offset of the arm slightly to prevent any interference with the nut and the rod ends, but a washer acts as a spacer and does the same thing.
My second mistake was that I had mounted both pivots into the cab the same way, with the interior arm pointed downward. After looking at the sweep I decided I wanted the park position and sweep direction to be opposite each other. They will park against the outside of the window and move toward each other in the center. That meant that one side needed to be a mirror image of the other. So I had to remove one of the pivots, file a new mounting tab on the opposite side of the hole so it could be mounted with the pivot arm pointing upward. Not a huge issue since the washer hides the other slot but not perfect. I could try and weld it closed but that will probably cause more trouble then it solves.
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