I can´t confirm the lock washer, but the ripped hole in the washer arm
has lost its teeth. Then, all you can do is replace the whole arm...and
hope the motor shaft still has its teeth.
Important when replacing windshield or similar work: Put arms back on
but regarding the teeth grooves, just not simply bolt the arm onto the
shaft.
Gentle wiggling, it´s not as hard of a material as expected...ummm, yeah

Regards,
Raimund

Am 29.05.2026 um 11:06 schrieb FRANK CONDELLI:
>          John et all, the wiper arms are made to slip in case they become stuck from ice, snow or other blockage.  If tightening the nut does not secure them the wiper arm shaft hole is worn out and needs to be replaced.  There is a lock washer behind the nut, it needs to be there as it is a very special lock washer, it’s outside diameter and inside diameter are very special sizes so that it fits over the first part of the splined shaft and the outside diameter allow the cap to be fitted.  I have these special washers in a larger thickness and some times that will fix the problem temporarily.  You can order them here:
>
> https://www.frankcondelli.com/staging1/store/index.php?route=product/product&path=135&product_id=1326 <https://www.frankcondelli.com/staging1/store/index.php?route=product/product&path=135&product_id=1326>
>
> Cheers,
>
> Frank Condelli
> Almonte, Ontario, Canada
> '87 VW Westy, '00 Kawasaki 250 Sherpa, "98 Ducati 750 Monster
> Vanagon/T3/Westfalia Parts and Accessories
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