A New Crankshaft Damper Needs To Be Installed And The Front Gear Train May Need To Be Modified On The Engine Of Certain 988F Loaders Caterpillar

A New Crankshaft Damper Needs To Be Installed And The Front Gear Train May Need To Be Modified On The Engine Of Certain 988F Loaders

Usage:

@media screen { div.divFooter { display: none; } } @media print { div.divFooter { position: fixed; bottom: 0; right: 0; } }

Caterpillar: Confidential Yellow

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.

NOTE: This Program must be administered as soon as possible. When reporting the repair, use "PI3677" as the Part Number, "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 "PI3677" as the Part Number, "7751" as the Group Number, "96" as the Warranty Claim Description Code, and "Z" as the SIMS Description Code.

NOTE: This Revised Service Letter replaces the December 24, 1993 Service Letter. Changes have been made to the Affected Product, Parts Needed, Service Claim Allowances, and Rework Procedure.

Completion Date

June 30, 1994

Termination Date

December 31, 1994

Problem

The 2W3878 Gear on the crankshaft may be misaligned and the 2P5149 Damper Assembly needs to be replaced on certain 988F Loaders. This Program needs to be performed due to updates and changes in procedures that may have been performed earlier.

Affected Product
Model & Identification Number

Group 1

988F (8YG88-161, 8YG163-193, 8YG196-222, 8YG224, 8YG226, 8YG227, 8YG229, 8YG231-241, 8YG243-248, 8YG250, 8YG254-261, 8YG263, 8YG265-267, 8YG269-273, 8YG275, 8YG276, 8YG278-281, 8YG283-289, 8YG293, 8YG295-303, 8YG305, 8YG307, 8YG309, 8YG311, 8YG313-315, 8YG217-319, 8YG321-323, 8YG325, 8YG326, 8YG329-335, 8YG337, 8YG338, 8YG340, 8YG343-345, 8YG347-351)

Group 2

988F (8YG162, 8YG194, 8YG195, 8YG223, 8YG225, 8YG228, 8YG230, 8YG242, 8YG249, 8YG252, 8YG253, 8YG262, 8YG264, 8YG268, 8YG277, 8YG282, 8YG290, 8YG294, 8YG304, 8YG306, 8YG320, 8YG324, 8YG336, 8YG339, 8YG341)

Group 3

988F (8YG301, 8YG346, 8YG352-359, 8YG361-364, 8YG366-372, 8YG374-381, 8YG383, 8YG384, 8YG386-393, 8YG396, 8YG397, 8YG399-405, 8YG407, 8YG411, 8YG412, 8YG418, 8YG419, 8YG421, 8YG422, 8YG424, 8YG426-428, 8YG430, 8YG433, 8YG434, 8YG437, 8YG443-451, 8YG453, 8YG455-465, 8YG468-473, 8YG476-479, 8YG488, 8YG490-494, 8YG496, 8YG498, 8YG507, 8YG520)

Parts Needed

Dealers will need to order parts for this Program.

Group 1 (Inspection Only)

1 2W1733 Seal Group

1 4W8089 Damper Assembly

Group 2 (And Group 1 If Gear Needs To be Replaced)

1 3F5792 Seal

1 5F0149 Ring

1 5F3106 Seal

1 7F2122 Seal-O-Ring

1 5H5672 Ring

1 6I3749 Gear Assembly

1 4N0933 Gasket

1 4N1151 Gasket

1 4N1946 Gasket

1 4N1998 Gasket

2 4N2199 Gasket

2 5P5678 M-Seal Stock

1 5P5846 Seal-O-Ring

1 5P8068 Seal

1 5P8119 Seal

1 4S5898 Seal-O-Ring

1 6V3830 Seal-O-Ring

1 6V4314 Seal-O-Ring

1 2W1733 Seal Group

1 2W3875 Gear

1 2W3878 Gear

1 4W5599 Gasket

1 4W8089 Damper Assembly

1 1008178 Gear Assembly

Group 3

1 4W8089 Damper Assembly

Action Required

See the attached procedure.

Owner Notification

U.S. and Canadian owners will receive the attached Owner Notification.

Service Claim Allowances

Group 1

NOTE: This is a 4.5-hour job.

Group 2

NOTE: This is a 28.0-hour job.

NOTE: Procedures for Group 2 Affected Product require the fabrication of an installation tool. In addition to the straightening tool mentioned above, each dealer may claim 4.0 hours of labor plus a maximum of $50 US for materials to fabricate this installation tool. Only one claim per dealership may be submitted for the fabrication of this tool.

Group 3

NOTE: This is a 4.0-hour job.

NOTE: U.S. and Canadian Dealers Only - This Program does not qualify for a Type 2 SIMS Report.

Parts Disposition

U.S. and Canadian Dealers

If the 6I3749 Gear, 2W3875 Gear, 2W3878 Gear and 1008178 Gear are replaced during this rework, return them to the address below:

Caterpillar Inc.
Service Claims Room
Attn. 3400 Vehicular Engine Serv. Engr.
8201 N. University
Peoria, IL 61615

All Other Dealers

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

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

Attach.

(1-Owner Notification)

(2-Rework Procedure)

COPY OF OWNER NOTIFICATION FOR U.S. AND CANADIAN OWNERS

Rework Procedure

NOTE: Even if the machine has already been reworked in accordance with the September 24, 1993 Service Letter, PI3660, it still needs to have a new 4W8089 Damper Assembly installed. Also, if the crankshaft gear runout measurement (obtained while performing PI3660) was:

- Less than .254 mm (.010 in) - Inspect the alignment of the crankshaft gear again following the updated rework procedures for Group 1, below.

-Between .254 mm (.010) in and .508 mm (.020) - And the gear was repositioned following procedures in PI3660, replace the front gear train following the rework procedures for Group 2.

Greater than .508 mm (.020 in) - Inspect the alignment of the crankshaft gear again following the rework procedures for Group 1, below.

Rework Procedures for Group 1

1. Remove the belts, crankshaft pulley, damper, and front crankshaft seal.

NOTE: Refer to the service manual for the correct tools and procedures for proper removal of the crankshaft seal.

2. Using a depth micrometer or a magnetic base dial indicator, check the distance from the front crankshaft face (where the damper contacts it) to the crankshaft gear. See Illustration 1.

NOTE: Two variables will be measured with this inspection procedure:

A. The runout of the front crankshaft gear.

B. The depth of the crankshaft gear on the crankshaft.

Caution must be used to ensure the stability and accuracy of the tools when performing the inspection procedure (the measuring devices must be anchored firmly). Use of a magnetic base with the dial indicator and the use of a depth micrometer with spacer blocks are examples of accessories used with measuring devices to ensure the stability of the tools.

Measuring Crankshaft Gear Runout

Illustration 1

3. Make twelve (12) measurements equally spaced between every hole of the crankshaft face. Be sure to record all measurements with a special notation for location of the minimum distance and the maximum distance. Calculate the runout of the gear by subtracting the minimum measured distance from the maximum measured distance.

4. If the runout measurement is .254 mm (.010 inch) or less, and the gear is within the specified distance from the front of the crankshaft, 27.68 ± 1.27 mm (1.090 ± .050 in) (refer to Illustration 1), the gear alignment is acceptable. Install a new 2W1733 Seal and a new 4W8089 Damper

5. If the runout measurement is greater than .254 mm (.010 in) or the face of the gear is not within the specified distance from the front of the crankshaft, 27.68 ± 1.27 mm (1.080 ± .050 in), or the gear was repositioned previously, replace the gear train and damper assembly in accordance with the Rework Procedures for Group 2, below.

Rework Procedures for Group 2

1. The front gear train must be replaced along with the front crankshaft damper.

2. Pin time the fuel pump and flywheel.

3. Support the front of the engine utilizing overhead support systems before proceeding with disassembly of the front gear train.

4. Drain the sump oil, remove the oil pan, front main bearing cap, and oil pump.

5. Remove the water pump and lines to allow removal of the front housing.

6. Remove the automatic timing advance cover and front housing.

7. To be able to move the camshaft forward;

A. Remove the 3T5447 Hydraulic Pump and drive from the flywheel housing.

B. Remove the rear 2W8038 Camshaft Gear.

8. Remove valve covers. Using the appropriate tools, pull the push rods and valve lifters out of the way (lifters need to pulled approximately an inch to allow movement of camshaft).

9. Remove the crankshaft gear using 1P2321 Puller Group. Heat the gear with a torch to ease its removal.

NOTE: Do not use excessive heat.

10. After removal of the crankshaft gear, check the front crankshaft gear journal dimension at four (4) equally spaced positions (12 O'clock, 1:30, 3:00, and 4:30). The correct dimension is 158.750 ± .025 mm (6.250 ± .001 inch) . If the journal is undersized, the crankshaft may need to be replaced. This requires removal of the engine from the machine. Before removing the engine, please contact the 3400 Service Engineer, Phone No. (309) 578-4436) or (309) 578-8629.

NOTE: The 2W3878 Crankshaft Gear should have a bore with an inside diameter of 158.620 ± .030 mm (6.245 ± .001 in) The interference fit between the gear and the crankshaft should be a minimum of .075 mm (.003 in).

11. Remove the camshaft thrust plate bolts to allow the camshaft to slide forward. Slide the camshaft forward no more than 38 mm (1.50 inch). To remove the 6I3749 Idler and Weight Gear Assembly, remove the 4 - 2B2695 Bolts, and then slide it forward the same distance as the camshaft was moved. This will allow access to the five bolts holding the 7N2484 Idler Drive Shaft to the block (See Parts Book SEBP2049 page 22, 6I3745 Front Gear Group). Once the five bolts are removed from the block, the drive shaft will be able to slide forward out of the block. The 6I3749 Idler and Weight Gear Assembly and drive shaft will now slide sideways away from the camshaft gear.

NOTE: The parts book does not show a 6I3749 Idler and Weight Gear Assembly. This is the parts service gear assembly for 6I3750 Gear Assembly and 4N0343 Sleeve Bearing.

12. Remove the 2W8375 Gear (Oil Pump) and 100-8178 Gear (Oil Pump Idler).

13. Install a new 2W3878 Gear onto the crankshaft.

NOTE: Before installing the crankshaft gear, fabricate a crankshaft gear installation tool. See Illustrations 2, 3, and 4. The crankshaft gear will need to be heated to 204° C (400° F), for 1 hour, before installation. Using adequate gloves to handle the heated gear, install the gear onto the crankshaft journal aligning the slot in the gear with the dowel in the crankshaft. (Elapsed time from removal of gear from oven/stove to installation on crankshaft should be no more than one (1) minute. Use the fabricated installation tool to finish pushing the gear to the proper depth location on the crankshaft. See Illustration 7. Once the tool is flush with the face of the crankshaft, tighten the two (2) bolts to hold the tool in place and check the gear, it MUST be flush with the installation tool. Some force may be required to align the gear if it has cocked during installation.

NOTE: After installation, check gear for acceptable runout and correct depth on crankshaft.

Installation Tool Plate

Illustration 2

Installation Tool Ring

Illustration 3

Installation Tool Assembly

Illustration 4

Installation Tool Mounted On Crankshaft Gear

Illustration 5

14. Install a new 6I3749 Gear Assembly (Idler Gear and Bearing Assembly), 1008178 Gear (Oil Pump Idler), and 2W3875 Gear (Oil Pump).

15. Slide the camshaft into its correct position and install the valve lifters and push rods. Install valve covers.

16. Install the rear camshaft gear, 3T5447 Hydraulic Pump and drive, automatic timing advance, timing gear cover, a new 2W1733 Seal, the crankshaft pulley, a new 4W8089 Damper, the belts, front engine support, oil pump, front main bearing cap, and oil pan. Replace the engine oil.