The Pistons And Rods For The Lift Cylinders Need To Be Reworked On Certain 994 Wheel Loaders To Accommodate A Larger Bolts Caterpillar

The Pistons And Rods For The Lift Cylinders Need To Be Reworked On Certain 994 Wheel Loaders To Accommodate A Larger Bolts

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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 "PI3591" 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 "PI3591" as the Part Number, "7751" as the Group Number, "96" as the Warranty Claim Description Code, and "Z" as the SIMS Description Code.

Completion Date

December 31, 1992

Termination Date

June 30, 1993

Problem

The bolts that hold the lift cylinder piston to the rod may fail on certain 994 Wheel Loaders. The pistons and rods need to be reworked to accommodate larger bolts.

Affected Product
Model & Identification Number

994 (9YF18-23)

Parts Needed

Dealers will need to order parts for this Program.

Parts Stock And Affected Product

1 - 6E0036 Seal Lip

1 - 6E0039 Seal U Cup

1 - 6E0245 Ring Wear

1 - 6E0246 Seal Assembly

1 - 6E0307 Seal Assembly

2 - 6E0308 Ring Wear

6 - 3S6162 Washer

6 - 6V6583 Bolt

NOTE: Quantities listed are per cylinder

Action Required

Parts Stock

Remove all new and exchange 9T9020 (standard) and 9T9023 (high lift) Lift Cylinders from parts stock. Rework the lift cylinders an described in the attached procedure.

Affected Product

See the attached procedure.

Owner Notification

Not Applicable.

Service Claim Allowances

NOTE: This is a 32-hour job to rework both of the lift cylinders.

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

Parts Disposition

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-Rework Procedure)

Rework Procedure

1. Remove the rod and the piston from the lift cylinders.

2. Drill out the 6 bolt holes in the rod assembly increasing the diameter to 36 mm and to a depth of 85 mm. Tap the bolt holes to 1 "1 × 12 threads 63 mm deep. See Illustration 1.

3. Increase the diameter of the 6 holes in the 6E0037 piston from 33 mm to 41 mm. See Illustration 2.

4. Grind 3 mm off of the outside diameter of the 3S6162. Washers to avoid interference between the washers during assembly.

5. On 1 side of the piston only, increase the 203.20 mm diameter to 210.00 ± 0.05 mm and to a depth of 32.0 ± 0.05 mm. See Illustration 2.

6. Stamp the new part number onto the piston: 101-0330. See Illustration 2.

7. Assamble the piston to the rod with the 203.20 mm diameter facing the rod. Tighten the piston bolts to a torque of 3600 ± 400 N·m (2700 ± 300 ft lbs). See Illustration 3.

8. Install the rod assembly into the cylinder.

9. Stamp the change level of the cylinder group for both the standard and highlift cylinders to Chg #04.

Illustration 1