PRODUCT IMPROVEMENT PROGRAM FOR INSPECTING THE TORQUE OF THE GENERATOR COUPLING BOLTS ON CERTAIN 794 AC, 796 AC, AND 798 AC OFF-HIGHWAY TRUCKS Caterpillar

PRODUCT IMPROVEMENT PROGRAM FOR INSPECTING THE TORQUE OF THE GENERATOR COUPLING BOLTS ON CERTAIN 794 AC, 796 AC, AND 798 AC OFF-HIGHWAY TRUCKS [UEBE0380]

POWER TRAIN

COUPLING GP

PRODUCT IMPROVEMENT PROGRAM FOR INSPECTING THE TORQUE OF THE GENERATOR COUPLING BOLTS ON CERTAIN 794 AC, 796 AC, AND 798 AC OFF-HIGHWAY TRUCKS

UEBE0380-03

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16Mar2020

(Revised 17Apr2020)

U-150

A-117

D-139

O-136

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Priority	PRODUCT IMPROVEMENT PROGRAM FOR INSPECTING THE TORQUE OF THE GENERATOR COUPLING BOLTS ON CERTAIN 794 AC, 796 AC, AND 798 AC OFF-HIGHWAY TRUCKS
4456 4450		PI33152

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NOTE:

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.

NOTE:

This Program must be administered as soon as possible. When reporting the repair, use "PI33152" 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 "PI33152" as the Part Number, "7751" as the Group Number, "96" as the Warranty Claim Description Code, and "Z" as the SIMS Description Code.

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NOTE:

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.

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NOTE:	This Revised Service Letter replaces the 16Mar2020 (Revised 26Mar2020) Service Letter. Changes have been made to the Parts Needed, Action Required, Service Claim Allowances, and Rework Procedure.

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COMPLETION DATE	TERMINATION DATE
30Sep2020	31Mar2021

PROBLEM

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The generator coupling bolts and shaft retention plate bolt need to be inspected for proper torque on certain 794 AC, 796 AC, and 798 AC Off-Highway Trucks. If the existing generator coupling bolts and/or the shaft retention plate bolt is under the torque specification the generator DE bearing assembly will have a loss of clamp force resulting in spline wear. In some cases, this has led to a generator shaft failure causing unplanned machine downtime.

AFFECTED PRODUCT

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Model	Identification Number
794 AC	HRT00101-00104 MT500113-00150
796 AC	HRZ00500, 503-507
798 AC	ST700401-00402

PARTS NEEDED

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Qty	Part Number	Description
1	6V5057	SEAL-O-RING (For trucks with Engine COF)
12	8T4193	BOLT-HEX HEAD
1	8T6381	BOLT-HEX HEAD
16	2194481	BOLT-HEX HEAD
1	2385084	SEAL-O-RING-STOR (For trucks with Engine COF)
2	2697885	SEAL-O-RING (For trucks with Engine COF)
In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 43% 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.

ACTION REQUIRED

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Refer to the attached Rework Procedure.
Refer to UENR5561 Centrifugal Oil Filter - Remove and Install
Refer to UENR2270 Power Generator - Remove and Install
Refer to UENR2270 Coupler Adapter and Mounting - Remove and Install
Refer to the Reuse & Salvage Guide SEBF9338
Refer to Special Instruction M0079855 Procedure for checking Crankshaft End Play
Refer to KENR9187 C175-16 Engine Crankshaft - Type 1 and Crankshaft - Type 2

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OWNER NOTIFIAVSION

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Owners in the following countries will receive the attached Owner Notification:
US
Canada

SERVICE CLAIM ALLOWANCES

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AVSpare		Dealer Suggested		Customer Suggested
Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
100%	100%	0%	0%	0%	0%

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NOTE: This is a 26.0-hour job
This is a 24 hour job, 2 additional hours are included for machines equipped with a Engine Centrifugal Oil Filter (COF) group.

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PARTS DISPOSITION

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Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.

MAKE EVERY EFFORT TO COMPLETE THIS PROGRAM AS SOON AS POSSIBLE.

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EXAMPLE COPY OF OWNER NOTIFIAVSION

XYZ Corporation
3240 Arrow Drive
Anywhere, YZ 99999

PRIORITY - PRODUCT IMPROVEMENT PROGRAM FOR INSPECTING THE TORQUE OF THE GENERATOR COUPLING BOLTS ON 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 generator coupling and retention bolts need to be inspected on the products listed below. The existing generator coupling and retention bolts can loosen leading to a generator failure causing unplanned machine downtime. 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 16Mar2020 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.

AVSpare Inc.

Identification #(s)

Attached to 16Mar2020 Service Letter

Rework Procedure

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1) Secure position for safe work. Remove the generator from the machine referring to the UENR2270 Power Generator - Remove and Install. If installed remove the Engine Centrifugal Oil Filter (COF) Group.

Image1.1.1

2) Check return to mark torque on 16x star hub bolts 620 +/- 80 Nm (457 +/- 59 ft lbs) and document results
....a) Mark the location of the bolt head relative to the stationary part
....b) Back off the bolt 1/4 turn
....c) Use a torque wrench to retighten the bolt and then compare to mark established in step a). Record if retightened mark indicates the bolt was not properly torqued from the factory.
....d) Repeat steps a) to c) on one bolt at a time and do not permanently loosen any bolt in the joint until the torque has been checked on all desired bolts.

3) Remove Coupling per UENR2270 "Coupler Adapter and Mounting - Remove and Install." Inspect against Reuse & Salvage Guide SEBF9338.

4) Check engine crankshaft endplay per Special Instruction M0079855. Refer to Specifications, KENR9187, "C175-16 Engine for 795F Series AC Off-Highway Trucks", Crankshaft -Type 1 and Crankshaft - Type 2 for crankshaft end play values.

5) Check return to mark torque on retainer plate bolt 540 +/- 70 Nm (400 +/- 50 ft lbs) and document results.
....a) Mark the location of the bolt head relative to the stationary part
....b) Back off the bolt 1/4 turn
....c) Use a torque wrench to retighten the bolt and then compare to mark established in step a). Record if retightened mark indicates the bolt was not properly torqued from the factory.
....d) Remove bolt, remove and inspect 390-2042 Drive Hub, remove grease from Generator splines.

If torque checks above showed the bolts were NOT properly torqued and the machine is past initial commissioning then move to Step 6 to complete additional inspections.

If torque checks above showed the bolts were all properly torqued or the machine has not yet been commissioned then additional inspections of the generator are not necessary:
Add Loctite Moly Paste to Generator splines. Install the drive hub and replace retainer bolt with new adding Loctite 263 and tightening to a torque of 540 +/- 70 Nm (400 +/- 50 ft lbs). Install the coupling with 16x new bolts and tighten to a torque of 620 +/- 80 Nm (457 +/- 59 ft lbs) to the Drive Hub. Refer to UENR2270 "Coupler Adapter and Mounting - Remove and Install. Install Generator and Coupling back into truck. Refer to the Disassembly and Assembly UENR2270, Power Generator - Remove and Install. If equipped reinstall the Engine Centrifugal Oil Filter (COF) group including a new 238-5084 Oil supply to COF base O-ring, two new 269-7885 radial O-rings on the drain back tube, and a new 6V-5057 O-ring at the interface to rear housing if removed.

6) Additional Inspections
....a) Inspect Generator Rotor Shaft spline with measurement over pins against print minimum.
.......i) Requirement: minimum measurement over pins 124.596 mm with 5 mm diameter pins
....b) Review if 484-2261 Sealing Ring (Slinger) component can move relative to Rotor Shaft
.......i) Requirement: no movement of Sealing Ring (Slinger) relative to Rotor Shaft.
....c) Measure distance from end of Rotor Shaft to Drive Hub face. The Drive Hub should stick out further than the Rotor Shaft.
.......i) Requirement: minimum distance 0.8mm (0.03 inches) Drive Hub relative to Rotor Shaft

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7. If any of the step 6 additional inspections do not meet the specifications work with your Dealer Tech Communicator (TC) to create a DSN - Product Health Service Request (SR) and choose Base Machine as the Workgroup Subsystem in the SR. The following information needs to be provided when creating the SR.

.... Repair Date
.... Machine Serial Number
.... Machine Hours
.... Generator Serial Number
.... Generator Part Hours
.... Inspection Values Actual vs Requirement Measurements
.... Include Photos of Component Wear

If all the step 6 additional inspections meet the specifications then:
Add Loctite Moly Paste to Generator splines. Install the drive hub and replace retainer bolt with new adding Loctite 263 and tightening to a torque of 540 +/- 70 Nm (400 +/- 50 ft lbs). Install the coupling with 16x new bolts and tighten to a torque of 620 +/- 80 Nm (457 +/- 59 ft lbs) to the Drive Hub. Refer to UENR2270 "Coupler Adapter and Mounting - Remove and Install. Install Generator and Coupling back into truck. Refer to the Disassembly and Assembly UENR2270, Power Generator - Remove and Install.If equipped reinstall the Engine Centrifugal Oil Filter (COF) group including a new 238-5084 Oil supply to COF base O-ring, two new 269-7885 radial O-rings on the drain back tube, and a new 6V-5057 O-ring at the interface to rear housing if removed.