Windshield Wiper Operation May Fail As A Result Of Excessive Tightening Of Mounting Hardware Caterpillar

Windshield Wiper Operation May Fail As A Result Of Excessive Tightening Of Mounting Hardware

Usage:

EXCAVATORS312B (6SW, 9NW),
312B L (9FS, 2KW),
315B L (5SW),
317B L (9WW),
317B LN (6DZ),
318B L (ADC),
318B LN (AEJ),
320B (1XS),
320B L (7JR, 9WS, 6LW),
320B LN (3YZ),
320B N (2AS),
320B S (5MS),
322B L (2ES),
322B LN (1ZS),
325B L (6DN, 4DS, 5BS),
325B LN (8FN),
330B L (3YR, 4RS, 5LS),
330B LN (5LR),
345B L (7KS, 2SW),
365B L (9PZ, 9TZ),
375 (6NK),
375 L (9WL),
5080 (6XK) EXCAVATORS

Problem:

The motor drive shaft may break and the mounting thread may become stripped for the windshield wiper. The cause may be due to excessive tightening to the nuts for mounting the components. The action may happen during factory assembly or when a field replacement is made. The result is the wiper blade may lack power, may have a bad sweep angle, or may stop operating completely.

Solution:

Two situations may take place during the installation of the wiper blades on the motors, that will cause the unsuitable wiper operation.

The first situation occurs when the wiper parallel link is installed on the motor support shaft. The torque specification must be followed strictly. The torque value for the M16 nut is 8.5 ± 1.5 N·m (76 ± 13 lb in). The threaded shaft is aluminum and any excess tightening will strip the thread or break the shaft. Any torque that is applied near 20 N·m (175 lb in) will weaken the shaft and threads.

The second situation concerns the stress that is placed to the drive shaft connection. The drive shaft is connected to a drive gear in the motor housing through a splined interference press fit. When the wiper blade is installed on the drive shaft, it is easy to over tighten the M8 nut. The specified torque value must be strictly held to 13.5 ± 1.5 N·m (121 1 13 lb in). Excessive tightening to the M8 nut will twist the drive shaft and cause it to slip in the drive gear. This act will result in slow movement, bad sweep angle, and/or no movement at all.

Manually moving the wiper blade in order to reposition it after the blade is mounted on the shaft will result in excessive torque on the drive shaft. This act will strip the connection between the drive shaft and the drive gear. In order to reposition the wiper blade, the M8 nut must be loosened and the blade removed from the drive shaft. After the position of the blade is changed, it can be installed on the shaft and the nut can be re-tightened. The M16 nut must be loosened in order to adjust the blade parallelism.

Suspect machines that may have wipers with operating problems are: 312B (6SW1-502, 9NW1-211), 312B L (9FS1-799, 2KW1-252), 315B L (5SW1-487), 317B L (9WW1-590), 317B LN (6DZ1-514), 318B L (ADC1-440), 318B LN (AEJ1-400), 320B (1XS1-927), 320B L (7JR1-2245, 9WS1-185, 6LW1-328), 320B LN (3YZ1-839), 320B N (2AS1-Up), 320B S (5MS1-578), 322B L (2ES1-859), 322B LN (1ZS1-552), 325B L (6DN1-1046, 4DS1-233, 5BS1-230), 325B LN (8FN1-1205), 330B L (3YR1-957, 4RS1-451, 5LS1-245), 330B LN (5LR1-715), 345B L (7KS1-630, 2SW1-135), 365B L (9PZ1-240, 9TZ1-331), 375 (6NK1-286), 375 L (9WL1-281), 5080 (6XK1-195) Excavators.

The following illustrations should be used in order to identify the components that are affected in the installation of the wiper blade to the drive shaft. Illustration 1. Illustration 2. Illustration 3.

Illustration 1.

Location of the lower windshield wiper. See Illustration 2 for Section A-A.

Illustration 2.

Position of components that are affected by tightening nuts excessively. This is a typical view. Refer to the identification of the callouts below Illustration 3.

Illustration 3.