PRODUCT IMPROVEMENT PROGRAM FOR REPLACING THE MAIN POWER CABLE AND INSPECTING AND REPLACING THE HARDWARE ON THE MAIN POWER RELAY IN THE CAB OF CERTAIN 794 AC, 796 AC AND 798 AC OFF-HIGHWAY TRUCKS
|7755 7499 1408||
AVSpare’s obligations under this Service Letter are subject to, and shall not apply in contravention of, the laws, rules, regulations, directives, ordinances, orders, or statutes of the United States, or of any other applicable jurisdiction, without recourse or liability with respect to AVSpare.
This Program must be administered as soon as possible. When reporting the repair, use "PI33197" as the Part Number and "7751" as the Group Number, "56" as the Warranty Claim Description Code and "T" as the SIMS Description code. Exception: If the repair is done after failure, use "PI33197" as the Part Number, "7751" as the Group Number, "96" as the Warranty Claim Description Code, and "Z" as the SIMS Description Code.
The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your AVSpare product analyst.
This Revised Service Letter replaces the 14Jul2020 (Revised 20Jul2020) Service Letter. Changes have been made to the Affected Product.
|The existing power cable to the main power relay in the cab may be loose on certain 794 AC, 796 AC and 798 AC Off-Highway Trucks. If the existing power cable is loose it may interfere with other components and may create a short circuit.|
|1||2418368||SWITCH AS-MAG (After Failure Only)|
|In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 45% of dealership population. This is an initial order recommendation only, and the ultimate responsibility for ordering the total number of parts needed to satisfy the program lies with the dealer.
|1||2418368||SWITCH AS-MAG (After Failure Only)|
|In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 35% of dealership population. This is an initial order recommendation only, and the ultimate responsibility for ordering the total number of parts needed to satisfy the program lies with the dealer.
|For Group 1 and Group 2, inspect the 241-8368 Switch As (main power relay) in the cab for the following:
(1) Loose power cable/ring terminal connection on main power relay
(2) Proper routing of main power cable to relay to avoid side loading of terminal stud
(3) The presence of insulation/heat shrink secured between terminals that could compromise the bolted joint
(4) Condition of studs on relay. Look for evidence of arcing and thread damage caused by over torquing
(5) Condition of relay housing. Look for evidence of past damage and cracking
(6) Check supplier date code located on relay housing
(7) Proper installation of any 3rd party systems to the relay to ensure the bolted joint is properly secured
For Group 2 only: Replace the existing 577-6265 Cable As. with new part number 597-2611 Cable As.
|Owners in the following countries will receive the attached Owner Notification:
SERVICE CLAIM ALLOWANCES
|NOTE: This is a 1.0-hour job for Group 1|
|NOTE: This is a 2.0-hour job for Group 2|
|Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.|
|MAKE EVERY EFFORT TO COMPLETE THIS PROGRAM AS SOON AS POSSIBLE.|
|EXAMPLE COPY OF OWNER NOTIFIAVSION
3240 Arrow Drive
Anywhere, YZ 99999
PRIORITY - PRODUCT IMPROVEMENT PROGRAM FOR REPLACING THE MAIN POWER CABLE AND INSPECTING AND REPLACING THE HARDWARE ON THE MAIN POWER RELAY IN THE CAB OF CERTAIN 794 AC, 796 AC AND 798 AC OFF-HIGHWAY TRUCKS
MODELS INVOLVED - 794 AC, 796 AC, and 798 AC Off-Highway Trucks
Dear Cat Product Owner:
The existing power cable to the main power relay in the cab may be loose on the products listed below. If the existing power cable is loose it can rub on other components and create a short. You will not be charged for the service performed.
Contact your local Cat dealer immediately to schedule this service. The dealer will advise you of the time required to complete this service.
If you are no longer the owner of this product(s), please contact your local Cat dealer so that our records can be updated. Please refer the dealer to their Service Letter dated 14Jul2020 when scheduling this service.
We regret the inconvenience this may cause you, and urge you to have this service performed as soon as possible to prevent unscheduled downtime.
Attached to 14Jul2020 Service Letter
|Note: Ensure that all safety information, warnings, and instructions are read and understood before any operation or any maintenance procedures are performed. Refer to the Operation and Maintenance Manual "Safety Section".
Refer to the Service Manual if/as necessary.
For Group 1 and 2:
1. Locate the 241-8368 Switch As (Main Power Relay) in the cab to check supplier date code. Ensure the relay has a date code of 5 Oct 2015 or newer. Replace relay if date code is not 5 Oct 2015 or newer. This date code can be found on the bottom of the relay as shown in Image 1.1.1.
2. Inspect the relay for damage on housing and terminal studs. Replace as required.
|3. Inspect the main power relay for a loose power cable/ring terminal connections and the presence of a 4B-4277 Washer on each power stud. If a 4B-4277 Washer is installed between the nut and the power cable/ring terminal it should be removed. This removed washer will not be re-used. Add an 8T-4224 Washer-Hard and 490-4245 Washer-Conical to each terminal stud as shown in Image 1.2.1.(for Group 2 trucks please note that the main power cable is being replaced) Apply silicone dielectric grease (Loctite 8423)to the stud threads prior to installing the nut and applying a torque of 12 +/- 0.5 Nm (106 +/- 4 lb in). It is critical that the nut not be over tightened as it can cause the copper studs on the relay to yield and loss of clamp force on the bolted joint will occur. While applying torque to the nut do not allow the main power cable terminal to rotate on the relay terminal.
Note: During the inspection for a loose connection it is important to confirm that the loose connection is between the relay terminal and cable/wire terminal. 1 to 2 deg of play between the terminal and relay housing can exists and this may give a false indication of a loose terminal.
Note: If damage is observed on power studs, replace 241-8368 Switch As (Main Power Relay). The torque value used to secure the main power relay to the cab is 4 Nm.
See Image 1.2.2. The washer-hard and washer-conical is missing between the nut and power cable/ring terminal. In addition, the ring terminal is not installed correctly, The gap underneath the ring terminal can potentially cause a loose connection. The wiring insulation on the ring terminal should not be in contact with the power cable terminal or power stud. Adjust wiring insulation/heat shrink on the ring terminal accordingly to avoid this condition.
4. Ensure that the main power cable is routed properly with enough slack so as not to side load the relay terminal.
5. Terminal connections to the main power relay to supply power for 3rd party systems need to be inspected to ensure they do not compromise the integrity of the original factory connection.
|For Group 2 trucks only:
6. Replace 557-6265 Cable As with 597-2611 Cable As shown in Image 1.3.1.
7. Inspect bolt torque at cab firewall junction block. For both 597-2611 Cable As routing from main power relay and 569-9690 Cable As routing up to junction block, bolts should be tighten to 35 +/- 5 Nm (310 +/- 44 lb in) as shown in Image 1.3.1. The torque required to secure the new cable to the relay is 12 +/- 0.5 Nm (106 +/- 4 lb in)