PIN 4Y1378 - Caterpillar

Engines:
G3606 (S/N: 3XF)
G3608 (S/N: 4WF)
G3612 (S/N: 1YG)
G3616 (S/N: 4CG)
Description of Change: A new coupling is available for the Hydrax actuator position sensors that are used on these engines that are equipped with the Hydrax System. The new coupling has improved durability. This new coupling has a three-piece design. The new coupling has two identical end pieces and the new coupling has one rubber spider that fits between the two end pieces.Adaptable To: The new 176-3572 Coupling (Assembly) is a direct replacement for the former 128-2354 Coupling (Assembly) on all of the Hydrax actuators. The only component of the new coupling assembly that is available for parts service is the 176-3571 Spider (1). Four M2.5 X 0.45 Hex socket head bolts (X) are used to fasten the new coupling end pieces (Y) to the shafts.Procedure to Replace the Former 128-2354 Coupling (Assembly) With the New 176-3572 Coupling (Assembly)
Illustration 1 g00736306
This illustration identifies the components of the new 176-3572 Coupling (Assembly). (1) 176-3571 Spider (X) M2.5 X 0.45 Hex Head Bolt (Y) Coupling End Piece
Stop the engine. Open the main electrical circuit breaker in order to remove power from the engine.
Disconnect the wiring harness from the Hydrax actuator position sensor.
Loosen the two screws of the 128-2354 Coupling (Assembly).
Remove the position sensor from the position sensor support housing.
Remove the 128-2354 Coupling (Assembly) from the shafts on each side of the coupling.Note: The shaft between the coupling and the position sensor will be loose. Do not drop this loose shaft.
Loosen the two bolts (X) in each coupling end piece (Y) of the new 176-3572 Coupling (Assembly).
Install the new 176-3572 Coupling (Assembly) on the main shaft. Install the loose piece of shaft into the other end of the new 176-3572 Coupling (Assembly). Evenly tighten the two bolts (X) on the position sensor side of the new coupling.
Install the position sensor support housing.
Install the position sensor.Note: Properly align the tab on the end of the loose shaft piece with the slot in the position sensor. The failure to properly align the shaft tab with the sensor slot can result in the following problems:
Damage to the position sensor
A poor output voltage reading
Generation of position sensor feedback fault code
The feedback voltage for the actuator position sensor can now be set. Refer to the Service Manual for the proper voltage setting procedure.
After the feedback voltage levels are set, evenly tighten the two screws (X) that are on the main shaft side of the new 176-3572 Coupling (Assembly).
Stroke the actuator linkage to the fully open position and stroke the actuator linkage to the fully closed position. Check the feedback voltages in order to ensure that the feedback voltages are within the specifications.Maintenance
The 176-3572 Coupling (Assembly) should be inspected after 5,000 hours of operation. If the rubber spider is worn or damaged, install a new 176-3571 Spider .