PRODUCT SUPPORT PROGRAM FOR UPDATING THE RETARDING GRIDS ON CERTAIN 795F AC OFF-HIGHWAY TRUCKS Caterpillar

PRODUCT SUPPORT PROGRAM FOR UPDATING THE RETARDING GRIDS ON CERTAIN 795F AC OFF-HIGHWAY TRUCKS

Usage:

TEBE3521-00

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15Sep2015

R120

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Containment - Before/After (Limited distribution)	PRODUCT SUPPORT PROGRAM FOR UPDATING THE RETARDING GRIDS ON CERTAIN 795F AC OFF-HIGHWAY TRUCKS
425R 1627 1437 3121 7750		PS90526

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NOTE:

Caterpillar’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 Caterpillar.

NOTE:

This Containment Program can be administered either before or after a failure occurs. In either case the decision whether to apply the Program is made by the dealer and service rep. Obtain the service reps Goodwill Approver Code before completing the repair. EAME dealers should use their standard Industry Group specific goodwill approval codes. The Goodwill Approver Code must be included when submitting the claim.

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NOTE:	When reporting the repair, use "PS90526" as the Part Number and "7777" as the Group Number. If administered before failure, use "56" as Warranty Claim Description and "T" as the SIMS Description Code. If administered after failure, use "96" as Warranty Claim Description Code and use "Z" as the SIMS Description Code.
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 Caterpillar product analyst.

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TERMINATION DATE

30Sep2016

PROBLEM

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Certain 795F AC Off-Highway Trucks may have the previous design fan blades in the retarding grid motor fan assembly.

The existing retarding grid mounting foot or hardware can be damaged. If the existing retarder grid foot fails, it can cause unplanned downtime and damage to the retarding grid.

The electrical insulators inside the electric retarding grid elements can wear and allow the ribbons inside the resistor elements to touch.

The existing retarding grid fan mounting bolts may become loose, missing or broken.

Severe road conditions at certain mine sites can cause fatigue cracks at the inner rear grid mounting foot, adjacent to the grounding cable.

AFFECTED PRODUCT

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Model	Identification Number
*****Group 1*****
795F AC	ERM00163-00164, 169, 271-276

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*****Group 2*****
795F AC	ERM00168, 205, 264, 270

PARTS NEEDED

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Qty	Part Number	Description
*****Group 1*****
16	4L6454	BOLT
22	4L9337	BOLT
16	5P1075	WASHER-HARD
16	6V8188	NUT-FULL
12	7X3392	WASHER-HARD
26	8T4121	WASHER-HARD
32	8T4821	WASHER-HARD
5	8T4835	BOLT
5	8T5911	NUT-WELD
28	8T8919	BOLT
4	9B7237	BOLT
16	2262659	WASHER
5	2923198	WASHER-HARD
1	4345144	BLADE AS
4	GUSSET	DEALER FABRICATED
1	PLATE	DEALER FABRICATED
In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 28% 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.
*****Group 2*****
16	4L6454	BOLT
22	4L9337	BOLT
16	5P1075	WASHER-HARD
16	6V8188	NUT-FULL
12	7X3392	WASHER-HARD
26	8T4121	WASHER-HARD
32	8T4821	WASHER-HARD
5	8T4835	BOLT
5	8T5911	NUT-WELD
28	8T8919	BOLT
4	9B7237	BOLT
16	2262659	WASHER
5	2923198	WASHER-HARD
1	4345144	BLADE AS
1	4526806	RESISTOR AS-PWR
1	4526807	RESISTOR AS-PWR
4	GUSSET	DEALER FABRICATED
1	PLATE	DEALER FABRICATED
In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 24% 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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All 434-5144 fan assembly and 349-7828 motor fan assembly must be set aside and inspected by the Caterpillar Service Technical Representative to determine the vintage of the motor fan blades.

The local Caterpillar dealer is to develop a component exchange strategy to remove/replace the Retarder Grid at PM to reduce machine downtime.

Dealer to perform the retarder grid rework at dealer repair facility outside of the customer mine.

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SERVICE CLAIM ALLOWANCES

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Product smu/age whichever comes first	Caterpillar		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
*****Group 1*****
0-30000 hrs, 0-60 mo	100.0%	100.0%	0.0%	0.0%	0.0%	0.0%

NOTE: This is a 20.0-hour job for Group 1
$60.00 (US) is allowed for material used to fabricate the parts for the grid mounting feet. No additional labor is allowed for the fabrication of the parts. Transportation of the Retarder Grid to/from the offsite facility will be the responsibility of the Cat Dealer. All reworks of this Containment Service Letter are required for the Service Letter to be approved by the Service Technical Representative. Pictures of all reworked areas are required to be loaded into SIMIs with the claim, along with the Grid Serial Number. This Serial Number plate will contain the part number 293-2208. Dealer is required to manufacture and label each updated grid with a Special Torque Sticker for Bolt Torques listed in this procedure.

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Product smu/age whichever comes first	Caterpillar		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
*****Group 2*****
0-30000 hrs, 0-60 mo	100.0%	100.0%	0.0%	0.0%	0.0%	0.0%

NOTE: This is a 20.0-hour job for Group 2
$60.00 (US) is allowed for material used to fabricate the parts for the grid mounting feet. No additional labor is allowed for the fabrication of the parts. Transportation of the Retarder Grid to/from the offsite facility will be the responsibility of the Cat Dealer. All reworks of this Containment Service Letter are required for the Service Letter to be approved by the Service Technical Representative. Pictures of all reworked areas are required to be loaded into SIMIs with the claim, along with the Grid Serial Number. This Serial Number plate will contain the part number 293-2208. Dealer is required to manufacture and label each updated grid with a Special Torque Sticker for Bolt Torques listed in this procedure.

PARTS DISPOSITION

Hold all parts for a Parts Return Request (PRR). A PRR will be issued to you through the Send-It-Back process after the claim is submitted. Make sure to list the service letter program number on the packing slip and include the closed work order paperwork. If you do not receive a Parts Return Request after 30 days, contact your service rep for guidance in obtaining it.

Rework Procedure

ON SITE REWORK PROCEDURE

Refer to KENR8727, Disassembly and Assembly, for removal and installation instructions for the grid, as required, in order to complete the Rework Procedure.
The retarder is mounted onto the right hand platform. Portions of the platform, under the retarder mounting, has dimples which creates an uneven mounting surface for the retarder.

1. Prior to removing the retarding grid, mark the footprint of the retarder grid.

2. Remove the retarder from the machine.

3. Grind off any dimples from the platform that are present under the retarder footprint. Refer to Image.

4. Repaint affected area.

5. Take a picture of the RH platform with the dimples removed for Service Claim. Picture to be uploaded into SIMSi.

6. The platform is now ready for the installation of a retarder.(Image 1.1.1)

Image1.1.1

OFF SITE REWORK PROCEDURE

Refer to Disassembly and Assembly, KENR8727, "Electric Retarder - Disassemble - Grid Assembly", and "Electric Retarder - Assemble - Grid Assembly".

1.Using a Permanent Pen, mark the element locations. Refer to the Service Manual if/as necessary and Follow the Disassembly Instructions in KENR8727 to remove all four Resistor Elements and the Intake Screen. (Image 1.2.1)

Image1.2.1

2. With the Grid Assembly laying with the grid fan down, locate and remove the bottom 5 mounting bolts.

NOTE: Removal of the 5 Mounting Bolts will allow the Grid Fan to become unsupported by the Grid Support Structure.(Image 1.3.1)

Image1.3.1

RETARDER GRID FAN ASSEMBLY PROCEDURE

Image1.4.1

1.With the fan assembly removed from the retarder grid, remove the bolts and the retaining plate from the top of the fan assembly.(Image 1.5.1)

2.Install the three guide pins into the holes as shown below.(Image 1.5.2)

3.Use fabric lifting straps that are rated to a minimum of 500 lbs, to lift the fan assembly off of the motor. Make certain that the fan is kept level and square to the rotor as to not make contact with the sides of the rotor coils. (Image 1.5.3)

Image1.5.1

Image1.5.2

Image1.5.3

4.Clean the stator assembly with compressed air. (Image 1.6.1)

5.Clean the top of the fan mounting surface with a soft cloth. (Image 1.6.2)

6.Clean the top and bottom of the mounting surface of the new fan assembly. (Image1.6.3 and 10 and Image1.6.4)

Image1.6.1

Image1.6.2

Image1.6.3

Image1.6.4

7.Carefully lower the new fan assembly over the guide pins and onto the stator. Make certain that the fan is kept level and square to the rotor as to not make contact with the sides of the rotor coils. (Image 1.7.1)

8.Remove the guide pins. (Image 1.7.2)

9.Apply a thin layer of RTV silicone around the bolt holes to prevent any moisture from entering the front of the fan assembly. (Image 1.7.3)

Image1.7.1

Image1.7.2

Image1.7.3

10.Install the retaining plate. (Image 1.8.1)

11.Place a thin layer of RTV silicone on the shank of the retaining bolts and re-install. (Image 1.8.2)

12.Tighten the bolts in an criss-cross pattern to 82 ft lbs. (Image 1.8.3)

Image1.8.1

Image1.8.2

Image1.8.3

13.Remove the conduit and the elbow from the old fan assembly and reinstall onto the new fan assembly. New electrical terminals will be provided by Cat.(Image1.9.1)

Image1.9.1

RETARDER GRID HARDWARE REWORK PROCEDURE

1.Locate and remove the existing weld nuts on the inside of the Grid Fan Support Structure. Use a grinder to remove the paint and any remaining weld material around the existing hole. (Image 1.11.1)

Image1.11.1

2.Once the weld nuts are removed, use a 3/4" (19 mm) drill to make a 1/4" (5 mm) deep recess at each of the bolt hole location on the inside of the Grid Support Structure. (Image 1.12.1)

3.Insert the new 8T-5911 weld nuts into each of 5 holes with the smaller diameter in the recessed area of the hole. Assure that the weld nut is resting flat on the Grid Support Structure and weld each nut into place. Once the material is cool, clean the area and apply a protective layer of paint. (Image 1.12.2)

Image1.12.1

Image1.12.2

4.Refer to the Service Manual if/as necessary and follow the Assembly Instructions in KENR8727 to reassemble the Retarding Grid.

Note: New hardware is required at the 5 Locations modified. (Image 1.13.1)

5.For the Quadrant Inner Diameter Plate Mounting shown in Image 1.13.2, use 16 of the 4L-6454 Bolt and 5P-1075 Washer, and tighten to a torque of 24 ft-lbs. (Image 1.13.2)

Image1.13.1

Image1.13.2

6.Use the Hardware Stack Up in Image 1.14.1 for Bolt Positions 1, 3, and 5.

Image1.14.1

7.Use the Hardware Stack Up in Image 1.15.1 for Bolt Positions 2, and 4.

Image1.15.1

8.Apply Loctite to the threads of each bolt and tighten to 105 NM +/- 20 NM.

9.For the Quadrant to Fan Mounting shown in Image 1.16.1, use 18 of the 4L-9337 Bolt and 8T-4121 Washer, and tighten to a torque of 24 ft-lbs.

Image1.16.1

10.For the Outlet Screen Outer Ring shown in Image 1.17.1, use 12 of the 8T-8919 Bolt and 7X-3392 Washer, and tighten to a torque of 58 ft-lbs.

11.For the Outlet Screen Inner Ring shown in Image 1.17.2 with the clearance holes, use 4 of the 9B-7237 Bolt and 8T-4121 Washer, and tighten to a torque of 24 ft-lbs.

12.For the Outlet Screen Inner Ring shown in Image 1.17.3 with the holding holes, use 4 of the 4L-9337 Bolt and 8T-4121 Washer, and tighten to a torque of 24 ft-lbs.

Image1.17.1

Image1.17.2

Image1.17.3

13.For the Power Terminal Mounting shown in Image 1.18.1, use 4 of the 8T-8919 Bolt and 226-2659 Washer, 8 of the 8T-4821 Washer, and 4 of the 6V-8188 Nut and tighten to a torque of 58 ft-lbs as shown in Image 1.18.2.

Image1.18.1

Image1.18.2

14.For the Bus Bar Mounting shown in Image 1.19.1, use 12 of the 8T-8919 Bolt and 226-2659 Washer, 24 of the 8T-4821 Washer, and 12 of the 6V-8188 Nut and tighten to a torque of 58 ft-lbs as shown in Image 1.19.2

Image1.19.1

Image1.19.2

RETARDER GRID REINFORCEMENT REWORK PROCEDURE

1.On the Retarder Grid (1), locate the Left Rear Mounting Foot (2) in Image 1.20.1.

2.Remove part of the existing top plate (3) leaving 1.5 inches of existing top plate. Grind a "V" notch in the existing crack and weld the crack as shown in Image 1.20.2

Image1.20.1

Image1.20.2

3.Fabricate a top plate (4) in Image 1.21.1 and four gussets (5) in Image 1.21.2 onto the Electric Retarder (1).

Image1.21.1

Image1.21.2

4.Affix one cap (4) to mounting bracket (2), evenly spaced on each side of the lower flange as shown in Image 1.22.1 and weld in place.

5.Place one gusset (5) on each side of the support bracket as shown in Image 1.22.2 Weld gussets in place.