Grand Cherokee 2WD V8-4.7L VIN J (2004)
Wiper Arm: Description and Operation
Front Wiper Arm
Fig. 11 Front Wiper Arm - Typical
FRONT WIPER ARM
The front wiper arms are the rigid members located between the wiper pivots that protrude 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 arm has a die cast metal pivot end with a large tapered mounting hole at one end. A molded black plastic cap fits over
the wiper arm retaining nut to conceal the nut and this mounting hole following wiper arm installation.
The wide end of a tapered, stamped steel channel hinges on and is secured with a hinge pin to the blade end of the wiper arm pivot end. One end of a
long, rigid, stamped steel strap, 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. Concealed within the stamped steel channel, one end of a long
spring 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 front 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 tapered mounting hole in the wiper arm pivot end
interlocks with the serrations on the tapered outer circumference of the wiper pivot shaft, allowing positive engagement and finite adjustment of this
connection. The mounting nut locks the wiper arm to the threaded stud of the wiper pivot shaft. 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.
