Wiper Arm: Description and Operation

The wiper arms are the rigid members located between the wiper pivots protruding from the cowl plenum cover/grille panel near the base of the windshield and the wiper blades on the windshield glass. These wiper arms feature an over-center hinge that allows easy access to the windshield glass for cleaning.

The wiper arms each have a die cast metal pivot end (3) with a large internally serrated socket formation at one end. A key (4) within the socket formation indexes the wiper arm to a keyway in the pivot shaft to provide wiper alignment, and a spring-loaded latch (5) on the underside of the pivot end locks the unit to the pivot shaft when it is fully installed. The right and left wiper arms for this model are not interchangeable, as the right wiper arm is slightly longer than the left one.

The wide end of a tapered, stamped steel channel (8) hinges on and is secured with a hinge pin (6) to the blade end of both the right and left wiper arm pivot ends. One end of a long, rigid, stamped steel strap (2), with a small hole near its pivot end, is riveted and crimped within the narrow end of the stamped steel channel. The tip of the wiper blade end of this strap is bent back under itself to form a small hook (1). Concealed within the stamped steel channel, one end of a long spring (7) is engaged with a wire hook on the underside of the die cast pivot end, while the other end of the spring is hooked through the small hole in the steel strap. The entire wiper arm has a satin black finish applied to all of its visible surfaces.

A wiper arm cannot be adjusted or repaired. If damaged or faulty, the entire wiper arm unit must be replaced.

The wiper arms are designed to mechanically transmit the motion from the wiper pivots to the wiper blades. The wiper arm must be properly indexed to the wiper pivot in order to maintain the proper wiper blade travel on the glass.

The serrated and keyed socket formation in the wiper arm pivot end interlocks with the serrations and keyway on the outer circumference of the wiper pivot shaft, providing positive engagement and alignment of this connection. The latch positively locks the wiper arm to the wiper pivot shaft when the arm is fully installed. The spring-loaded wiper arm hinge controls the down-force applied through the tip of the wiper arm to the wiper blade on the glass. The hook formation on the tip of the wiper arm provides a cradle for securing and latching the wiper blade pivot block to the wiper arm.