There are two common points of excess wear or failure. The first is on the shafts that drive the wiper arms The second is at the ends of the ball socket joints on the connecting rods that drive the shafts. In the video and pictures here you will see what happens when these mechanisms are not properly lubricated on a regular basis.
Problem & Solution
Common among these chassis:
Look what happened on the green W123 chassis 240D when the wiper shafts were neglected. When these wear out it can be an expensive repair. Lube these shafts yearly with a penetrating grease. You also have to check the drain areas. The problem on the W123 can be accelerated when the water drain hole gets plugged on the passenger side (as it did in this case). Look at the amount of rust created due to standing water around the shaft. This happened on a well maintained car!
In most cases you will only need to remove the wiper arm and the plastic cover to lube the shaft properly. Install new covers (only 126 chassis are available on our website 123 covers are no longer made) if your old covers are cracked or damaged. Use Miracle Paint to coat any rust to keep it from growing.....
In both the green car and the silver 126 in the video we had to remove the complete drive assembly under the top panel. The 123 was too far gone and we had to replace it with a good used unit. The video will clearly show what happens when the ball joints on the drive rods do not get lubricated.
WARNING: These wiper drive mechanisms are something you MUST take care of. Replacements are no longer available new.