Installation Procedure for Upgrading the Low-Pressure Fuel System For Certain C175 Powered Off-Highway Trucks {1256, 1274} Caterpillar

Off-Highway Truck/Tractor

793F (S/N: SND1-UP; SSP1-UP; SXP1-UP; RBT1-UP)

793F AC (S/N: EMD1-UP)

794 AC (S/N: MN51-UP; MT51-UP)

795F AC (S/N: ERM1-UP)

795FAC XQ (S/N: SNT1-UP)

797F (S/N: LAJ1-UP; WSP1-UP)

Introduction

Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.

Before updating to the new transfer pump and fuel line routings, ensure the priming pump and mono-block changes announced in SEPD1930, have already been performed. REHS9674 was created to document a procedure to perform the priming pump and mono-block update.

Safety Section

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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine.

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Personal injury or death may result from failure to adhere to the following procedures. Fuel leaked or spilled onto hot surfaces or electrical components can cause a fire. Clean up all leaked or spilled fuel. Do not smoke while working on the fuel system. Turn the disconnect switch OFF or disconnect the battery when changing fuel filters.

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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue, causing serious injury, and possible death. Always use a board or cardboard when checking for a leak. Do not check for pin hole leaks in pump or motor hoses during a steer stall condition. If fluid is injected into your skin, it must be treated by a doctor familiar with this type of injury immediately.

Do not perform any procedure in this special instruction until you have read this special instruction and you understand this information. Use only proper tools and observe all precautions that pertain to the use of those tools. Failure to follow these procedures can result in personal injury. The following procedures should also be observed.

Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs.

A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly.

Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard.

Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If the tools, the procedure, and the work method are not recommended by Caterpillar, ensure that the tools, the procedure, and the work method are safe.

Ensure that the product will not be damaged or the product will be made unsafe by the operation, lubrication, maintenance, or the repair procedures.

16 Cylinder Required Parts

20 Cylinder Required Parts

16 Cylinder Fuel Group Removal Procedure

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Illustration 1	g06020730

1. Remove the fuel lines and the parts in red in the illustration above.
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   Illustration 2	g06020752
   (1) 6V-7673 Bolt (2) 5P-8245 Washers (3) 344-2936 Bracket (4) 6V-8197 Bolt (5) 208-9281 Bolts (6) 9M-1974 Washers (7) 377-9341 Fuel Transfer Pump As (8) 284-8347 Coupling

2. Remove Bolts (1), (4), and (5) with washers (2) and (6).

3. Remove bracket (3), fuel pump (7), and coupling (8).
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   Illustration 3	g06169172
   (9) Bolt

4. Remove four bolts (9) from the rear of the fuel pump.

   Note: DO NOT remove the rear flange/Cover from the fuel pump. Removal of this flange/cover will result in internal damage to the fuel pump and premature failure.

5. Remove 365-5949 Engine Harness As and 463-5276 Engine Harness As.

16 Cylinder Fuel Group Installation Procedure

1. Install 500-0614 Engine Harness As and 500-0615 Engine Harness As using the same hardware that was removed previously.
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   Illustration 4	g06085289
   (1) 436-9090 Fuel Manifold (2) 230-3728 O-Ring Seal (3) 241-6157 Plug (4) 228-7100 O-Ring Seal (5) 6V-1819 Bolt (6) 6V-5839 Washer (7) 2Y-5829 Nut

2. Install manifold (1) to fuel filter base with three seals (2), plug (3), O-Ring Seal (4), eight washers (6), four bolts (5), and four nuts (7).
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   Illustration 5	g06085306
   (8) 360-3681 Plug (9) 235-5081 O-Ring Seal (10) 227-0136 Plug (11) 228-7105 O-Ring Seal

3. Install plug (8) and O-Ring (9) in top of manifold.

4. Install two plugs (10) and O-Rings (11) on rear facing side of manifold, leaving the center port open for the fuel temperature sensor.
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   Illustration 6	g06085382
   (12) 481-1441 Adapter (13) 5D-5958 O-Ring Seal (14) 095-0673 Bolts

5. Install adapter (12) with four bolts (14) and O-ring (13) to the back side of the fuel pump.
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   Illustration 7	g06085396
   (15) 460-2162 Bracket As. (16) 7D-1649 Washers (17) 6V-8336 Bolts (18) 453-1566 Fuel Transfer Pump As (19) 445-2070 Check Valve Gp (20) 485-8900 Bracket (21) 6V-7673 Bolt (22) 5P-8245 Hard Washer (23) 6V-8197 Bolt (24) 7D-1649 Hard Washer

6. Install fuel transfer pump (18) to adapter (12) with check valve (19), bracket (15), two washers (16), two Bolts (17), two bolts (23), and two washers (24).

   Note: Pump (18) will need to be rotated counter-clockwise while holding bracket (15) against the pump.

7. Install bracket (20) to the engine with bolts (21) with washers (22).
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   Illustration 8	g06251538

8. Install tee (25) with O-Ring (29) to manifold with connectors (28) with O-ring (30).

9. Install elbow (31) with O-Ring (30) to bottom of manifold facing towards rear of engine.

10. Install connect (26) with O-Ring (27) to the tee (25).
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    Illustration 9	g06090708
    (32) 489-7600 Tube As (33) 228-7090 O-Ring Seal (34) 4I-7889 Spacer (35) 4P-0707 Clamp As (36) 8T-0355 Bolt (37) 6V-5839 Washer (38) 493-1654 Hose As (39) 228-7091 O-Ring Seal (40) 369-6670 Check Valve (41) 228-7105 O-Ring Seal

11. Install tube (32) with O-Ring (33) with spacer (34), clamp (35), bolt (36), and washer (37).

12. Install hose (38) with O-Ring (39) to tee (25) and priming pump with check valve (40) and O-Ring (41).
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    Illustration 10	g06021284
    (42) 241-6158 Plug (43) 228-7102 O-Ring Seal (44) 456-7100 Hose (45) 228-7092 O-Ring Seal (46) 439-4777 Check Valve (47) 238-5083 O-Ring Seal (48) 6V-8635 Connector (49) 238-5084 O-Ring Seal (50) 228-7093 O-Ring Seal (51) 439-1834 Cross Adapter

13. Install connector plug (42) and O-Ring (43) in three places on the back of the fuel manifold.

14. Install check valve (46) with O-Ring (47) to the backside of the fuel transfer pump.

15. Install hose (44) to the check valve (46) with O-Ring seal (36). The other end of the hose should connect to the elbow in the bottom of the fuel filter base.

16. Install cross adapter (51) to transfer pump with O-Ring (49). Install connector (48) to the cross adapter (51) with O-Ring (49).
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    Illustration 11	g06085857
    (52) 485-8899 Hose As (53) 438-2169 Hose As (54) 228-7091 O-Ring Seals (55) 6V-9838 Swivel Tees (56) 306-7666 Orifice (57) 228-7090 O-Ring Seals (58) 228-7105 O-Ring Seals (59) 281-5958 Connector (60) 459-8418 Pressure Regulator (61) 482-3477 Hose As (62) 474-2631 Adapter (63) 482-3478 Hose As (64) 8T-1889 Clip (65) 8T-1890 Clip (66) 353-7953 Grommet (67) 482-3479 Hose As

17. Install swivel tee (55) with O-ring (54) onto base pump.

18. Install hose (52) to adapter on the fuel transfer pump and onto swivel tee (55) and secure with clips and grommets (64), (65), and (66).

19. Install hose (53) to swivel tee (55) and to pressure regulator (60) with O-rings (54) and (58).

20. Install orifice (56) with O-rings (57) and (58) to fuel filter base.

21. Install connector (59) with O-rings (57) and (58) to fuel filter base.
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    Illustration 12	g06085924

22. Install hose (61) with O-rings (57) and connector (59) with O-Ring (58) and adapter (62) with O-Ring (57).

23. Install hose (63) with clips (64), (65) and grommet (66) with O-rings (57).
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    Illustration 13	g06085998

24. Install hose (67) with O-Rings (57) to front side of fuel base.

20 Cylinder Fuel Group Removal Procedure

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Illustration 14	g06021814

1. Remove the fuel lines and the parts in red in the illustration above.
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   Illustration 15	g06021865
   (1) 5C-9563 Spacer (2) 7S-3916 Clip (3) 7S-3919 Clip (4) 318-0820 Grommet (5) 6V-7730 Bolt (6) 091-9035 Spacer (7) 6V-5843 Bolt

2. Remove bolt (5) with grommet (4), clips (2), (3), and spacer (1).

3. Remove bolt (7) with spacer (6).
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   Illustration 16	g06022106
   (8) 330-9724 Connector Plug As (9) 333-9177 Hose As (10) 8C-8989 Elbow (11) 228-7090 O-Ring Seal (12) 326-1443 Check Valve Gp (13) 344-2936 Bracket (14) 5P-8245 Hard Washers (15) 6V-7673 Bolts (16) 6V-8197 Bolt (17) 313-9062 Fuel Transfer Pump Gp (18) 330-9725 Plug As (19) 452-0434 Tee As (20) 438-7211 Check Valve Gp

4. Remove plug (8), hose (9) elbow (10), O-ring (11), and check valve (12) from the fuel manifold.

5. Remove plug (18), tee (19), and check valve (20) from the fuel transfer pump (17).

6. Remove bracket (13), three washers (14), two bolts (15) and bolt (16).

7. Remove the four 383-2035 Fuel Injection Pump Gp

8. Remove fuel transfer pump (17) from the rear of the fuel pump.
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   Illustration 17	g06169171
   (21) Bolt

9. Remove four bolts (21) from the rear of the fuel pump.

   Note: DO NOT remove the rear flange/Cover from the fuel pump. Removal of this flange/cover will result in internal damage to the fuel pump and premature failure.

10. Remove 365-5949 Engine Harness As and the 463-5285 Engine Harness As.

20 Cylinder Fuel Group Installation Procedure

1. Install 500-0614 Engine Harness As and 500-0616 Engine Harness As. Use mounting hardware from the harness assemblies that were previously removed.
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   Illustration 18	g06086366
   (1) 436-9090 Fuel Manifold (2) 230-3728 O-Ring Seals (3) 6V-1819 Bolts (4) 6V-5839 Washers (5) 2Y-5829 Nuts (6) 459-8418 Pressure Regulator (7) 228-7105 O-Ring Seals (8) 228-7091 O-Ring Seal (9) 314-2490 Adapter (10) 228-7100 O-Ring Seal (11) 260-9229 Connector (12) 306-7666 Orifice (13) 228-7090 O-Ring Seal (14) 360-3681 Plug (15) 238-5081 O-Ring Seal (16) 503-2216 Adapter

2. Install fuel manifold (1) with three O-rings (2), four bolts (3), eight washers (4), and four nuts (5) to the fuel filter base.

3. Install pressure regulator (6) to fuel manifold with O-rings (7) and (8).

4. Install adapter (9) to the bottom of the fuel manifold with O-ring (10).

5. Install plug (11) with O-ring (7) in the middle port on the fuel manifold.

6. Install orifice (12) with O-rings (7) and (13) on the left port on the fuel manifold.

7. Install plug assembly (14) on the top left port and bottom left of the fuel manifold with 238-5081 O-Ring Seal (15).

8. Install adapter (16) with 238-5081 O-Ring Seal and 228-7090 O-Ring Seal on the top middle port of the fuel manifold.

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Illustration 19	g06026330
(17) 460-2163 Bracket As (18) 7D-1649 Hard Washers (19) 6V-8336 Bolts (20) 439-1834 Cross Adapter (20) 238-5084 O-Ring Seal (21) 6V-8635 Connector (22) 453-1566 Fuel Transfer Pump As (23) 445-2070 Check Valve Gp (24) 435-9853 Coupling (25) 241-6158 Plug (26) 8T-7488 Connector (27) 228-7102 O-Ring Seals (28) 481-1441 Adapter (29) 095-0673 Bolts (30) 5D-5958 O-Ring Seal (31) 419-7158 Elbow Adapter (32) 6V-7673 Bolt (33) 5P-8245 Hard Washer (34) 6V-8197 Bolt

1. Install adapter (28) with four bolts (29) and O-ring (30) to rear of fuel pump.

2. Install fuel transfer pump (22) to adapter (28) with check valve (23) and coupling (24).

3. Install bracket (17) with two washers (18) and bolts (19) to the pump and two washers (18), one bolt (19), and one bolt (34).

4. Install adapter (20) with 238-5084 O-Ring Seal, connector (21) with 238-5084 O-Ring Seal, and elbow (31) with 238-5083 O-Ring Seal to the fuel transfer pump.

5. Install connector plug (25) and connector (26) with O-rings (27).
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   Illustration 20	g06022528
   (35) 443-3687 Hose As (36) 228-7090 O-Ring Seal (37) 482-3477 Hose As (38) 228-7090 O-Ring Seal (39) 6V-9838 Swivel Tee (40) 422-8374 Hose As (41) 228-7091 O-Ring Seal (42) 316-0487 Spacer (43) 8T-1889 Clip (44) 8T-1890 Clip (45) 353-7953 Grommet (46) 198-4766 Hard Washer (47) 8T-0356 Bolt

6. Install hose (35) with O-Ring (36) and hose (37) with O-Ring (38) from the rear fuel pump manifold to the fuel manifold mounted on the fuel filter base.

7. Secure hose (35) with spacer (42), clips (43), (44), grommet (45), washer (46), and bolt (47).

8. Install swivel tee (39) to the fuel transfer pump, then install hose (40) from the fuel manifold on the fuel filter base to swivel tee (39).
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   Illustration 21	g06022553
   (8) 228-7091 O-Ring Seal (48) 457-7752 Hose As

9. Install hose (48) from the fuel transfer pump to the fuel priming pump.
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   Illustration 22	g06086022
   (7) 228-7105 O-Ring Seal (49) 422-8374 Hose As (50) 8C-7563 Elbow (51) 228-7091 O-Ring Seal (52) 493-6425 Elbow (53) 228-7092 O-Ring Seal (54) 281-5873 Connector (55) 228-7093 O-Ring Seal (56) 323-9923 Check Valve Gp

10. Install connector (54) to the front fuel filter base with O-rings (7). Install elbow (52) to connector (54) with O-rings (55). Install check valve (56) to elbow (52) with O-rings (53). Install elbow (50) to elbow (52) with O-rings (51).

11. Install hose (49) to the fuel priming pump and elbow (50) with O-ring (51).
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    Illustration 23	g06086290
    (4) 6V-5839 Washers (36) 228-7090 O-Ring Seal (53) 228-7092 O-Ring Seal (57) 489-7601 Hose and Tube As (58) 4I-7889 Spacer (59) 4P-0707 Clamp As (60) 8T-0355 Bolt (61) 4P-3563 Clamp As (62) 090-8635 Spacer (63) 8T-5005 Bolt (64) 478-0101 Hose and Tube As (65) 6V-9873 Adapter (66) 214-7568 O-Ring Seal (67) 314-2446 Bracket

12. Install adapter (65) to elbow (52) with O-ring (66).
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    Illustration 24	g06022660

13. Install hose and tube assembly (57) with O-ring (36) to the fuel manifold and to the elbow (52) with connector (65), and O-ring (66).

14. Secure hose and tube assembly (57) with washer (4), spacer (58), clamps (59), and bolt (60).

15. Install hose and tube assembly (64) with O-ring (53) to front of fuel filters on the check valve and to the elbow on the fuel transfer pump.

16. Secure hose and tube assembly (64) with clamps (61), spacers (62), and bolts (63), washer (4), and bracket (67).
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    Illustration 25	g06086315
    (68) 4P-3563 Clamp As (69) 8T-5005 Bolt (70) 6V-5839 Washer (71) 314-2446 Bracket (72) 090-8635 Spacer

17. Install spacer (72), bracket (71), clamp (68) to the tube assembly. Secure clamps with bolts (69) and washers (70) to the bracket.