Over the years, the wiper arms have been mounted on the wiper shaft in two ways, by means of a clamping system on the wiper arm and the younger system uses a conical coupling. In the latter case, the wiper arm is fixed to the axle by a nut, which remains visible for the years of construction for which the cap nuts mentioned here are provided.
The cap nuts are made of aluminium, which has two major advantages: first, the cap nut is always visible and does not rust and, second, when tightened too tightly, the nut is damaged and not the thread of the axle.
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