Usage:
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 can be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS4737" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code. If administered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
NOTE: Although this Program is to be administered as described above on the Affected Product, parts should be removed from parts stock as soon as possible.
NOTE: This Revised Service Letter replaces the April 29, 1992 (Revised June 1992) Service Letter. Various changes have been made to split the Affected Product into three groups instead of two.
Termination Date
April 30, 1993Problem
The fuel lines on certain D9N Tractors, 589 Pipelayers, 631E Tractors, 637E Tractors, 657E Scrapers, 768C Tractors, 769C Trucks, 834B Tractors, and 988B Loaders may fail. New fuel line groups can be installed that have a longer service life.
Affected Product
Model & Identification Number
Group 1
D9N (1JD1288, 1JD1295, 1JD1296, 1JD1298-3280)
589 (31Z423-469)
631E (1AB965-1456; 1NB769-771)
637E TR (1FB361-537; 1JB612-724)
657E SC (90Z186-209; 91Z317-448)
768C (02X360-370)
769C (01X4394, 01X4403, 01X4418, 01X4420-5960)
Group 2
988B (50W08961, 50W8962, 50W8964-11257)
Group 3
834B (92Z368, 92Z370, 92Z373-512)
Parts Needed
Group 1
- 4 - 4B4274 Washer
- 2 - 7C6525 Fuel Line Clamp
- 2 - 7C6589 Fuel Line Clamp
- 1 - 6I0030 Lines Group
- 6 - 5M2894 Washer
- 4 - 9N3388 Screw
- 6 - 0S0509 Bolt
- 2 - 7C6525 Fuel Line Clamp
Group 2
- 4 - 4B4274 Washer
- 2 - 7C6525 Fuel Line Clamp
- 2 - 7C6589 Fuel Line Clamp
- 1 - 6I0030 Lines Group
- 11 - 5M2894 Washer
- 4 - 9N3388 Screw
- 1 - 4P8261 Bracket
- 1 - 4P8385 Bracket
- 2 - 5P0537 Washer
- 5 - 0S1571 Bolt
- 6 - 0S0509 Bolt
- 2 - 0S1615 Bolt
- 3 - 8T1296 Washer
- 1 - 1010462 Rod
- 2 - 7C6525 Fuel Line Clamp
Group 3
- 4 - 4B4274 Washer
- 2 - 7C6525 Fuel Line Clamp
- 2 - 7C6589 Fuel Line Clamp
- 1 - 1029884 Lines Group
- 4 - 9N3388 Screw
- 5 - 5M2894 Washer
- 4 - 0S0509 Bolt
- 1 - 0S1594 Bolt
- 2 - 7C6525 Fuel Line Clamp
Action Required
Parts Stock
Remove all 7C6931, 7C6932, 7C6933, 7C6934, 7C6935, 7C6936, 7C6937, and 7C6938 Fuel Lines from parts stock.
Affected Product
Remove the existing fuel lines and install the new fuel injection line group as a group. Do not disassemble the fuel line groups and install them one line at a time. See the attached (pending) procedure.
NOTE: Do not over tighten the screws of the metal-to- metal fuel line clamps. Use a 6V6069 Torque Screwdriver or similar tool to tighten the screw to a torque of 2.25 N·m (20 lb.in.).
Service Claim Allowances
Parts Stock
Submit one claim for all 7C6931, 7C6932, 7C6933, 7C6934, 7C6935, 7C6936, 7C6937, and 7C6938 Fuel Lines removed from parts stock.
Affected Product
NOTE: This is a 3-hour job.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Attach. (1-Rework Procedure)
Rework Procedure
Refer to the parts list and illustrations. Replace the existing fuel lines and their related parts with the new parts listed for each group.
NOTE: To insure that the clamp locations are correct, install fuel line group as assembled. In a case where it is necessary to remove the clamps, mark their locations to insure correct positions when assembling.
1. Clean and paint the new 6I0030 or 102-9884 Fuel Line Group before proceeding to the job site.
A) Install 5F2807 Plastic Caps and 2F2990 Plastic Plugs on the ends of the lines.
B) Clean and paint the fuel line group.
C) After drying, do not remove the plastic plugs and caps until the fuel line group is ready to be installed on the engine. Transport the fuel line group in it's original shipping box.
2. Remove all mounting bolts from the fuel line brackets at the aftercooler housing. New mounting bolts and washers will be used. Keep the washers. The washers may be needed later as spacers.
3. Remove the existing three line clamps from the 9Y4577 Bracket which is attached to the backside of the fuel injection pump (See Illustration 1). New 7C6525 Clamps, 7C6589 Clamps, 9N3388 Screws, and 4B4274 Washers are used to attach the new fuel line group to the 9Y4577 Bracket.
4. Disconnect all the fuel line nuts at the fuel injection pump and at the adapters in the valve cover bases.
5 Remove the old fuel line group. Remove the plastic plugs and caps from the 6I0030 or 102-9884 Fuel Line Group. Set the new fuel line group in place and hand tighten the fuel line nuts.
NOTE: Do not force the ends of the lines into place and start the fuel line nuts. This puts unwanted strains on the fuel lines. If any of the ends of the individual fuel lines are not square with the bonnets of the fuel injection pump or the adapters in the valve cover bases, gently bend the lines by hand to align the ends before starting the fuel line nuts.
5 b) Group 2 Affected Product Only - 988B Non-Aftercooled Affected Product not having an aftercooler on engine require installing a different fastener support group and throttle linkage rod. The 1010462 Rod replaces the 9U0238 Rod (part of the governor control group) because of interference with the new bracket assembly. The former 6N1671 Support Bracket was used to fasten the fuel line brackets (that fasten to the aftercooler housing on aftercooled engines). Illustration 2 shows pictures of how the new 6N1672 Fastener Group is installed. The 4P8385 Bracket and 4P8261 Brackets are the 2 main parts of this group. Five 0S1571 Bolts and five 5M2894 Washers attach the assembly to the block. To align the assembly correctly, three 8T1296 Washers are required to shim the brackets to block (see Illustration 2 Part 2 of 2). Use two 0S1615 Bolts and two 5P0537 Washers to attach the brackets together. After the new 6N1672 Fastener Group and 1010462 Rod are installed, the new 6I0030 Fuel Line Group can be installed.
6. Install new 7C6525 and 7C6589 Fuel Line Clamps on the 9Y4577 Bracket. (See Illustration 1). Tighten screws to a torque of 2.25 N·m (20 lb.in.).
NOTE: Do not over tighten the screws. Use the 6V6069 Torque Screwdriver or similar tool to tighten screws.
7 A) Groups 1 and 2 Affected Product Only - Use six 0S0509 Bolts and six 5M2894 washers to attach the fuel line brackets to aftercooler housing (See Illustration 1).
7 B) Group 3 Affected Product Only - Use four 0S0509 Bolts, one 0S1594 Bolt and five 5M2894 washers to attach the fuel line brackets to the aftercooler housing. See Illustration 4.
NOTE: Normally the brackets will fit correctly on the aftercooler housing. If there are gaps, use the washers removed in Step 2 as spacers to fill in the gaps. The purpose of the washers is to prevent the brackets from putting unwanted strains on the fuel lines.
8. Tighten bracket mounting bolts for the brackets.
9. Use the hand priming pump to purge air out of the fuel lines. The fuel line nuts at the adapters in the valve cover bases may need to be loosened to allow air to escape. Tighten the fuel line nuts finger tight as the air is purged from the lines.
10. Tighten all of the fuel line nuts to a torque of 40 ± 7 N·m (30 ± 5 lb ft).
11. Wipe up all spilled fuel.
12. Start engine to purge any remaining air and make sure there are no fuel leaks.
13. Shut the engine off and tighten all of the fuel line nuts again. Tighten them to a torque of 40 ± 7 N·m (30 ± 5 lb ft) as done previously in Step 10.
14. Paint any needed areas of the fuel lines/brackets as needed.
Illustration 1 - Group 1 & 2 Affected Product
Illustration 2 - Part 1 of 2 - Top View
Illustration 2 - Part 2 of 2 - Left Side View
Illustration 3 - Part 1 of 2 - Front Right View
Illustration 3 - Part 2 of 2 - Left View
Illustration 4 - Group 3 Affected Product