A New Accumulator Studs And Washers Are Now Available For Certain 3512 Engines {1252, 1254} Caterpillar

Petroleum Engine

3512E (S/N: SK31-UP; SK51-UP)

Pumper

SPF743 (S/N: MLX1-UP)

The new stud and washer available help prevent failure due to high-cycle fatigue.

Table 1 contains the new part numbers that are available. Follow the directions below for installation of the new parts.

Safety Section

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Do not open the high pressure fuel system without allowing the fuel system to purge. After the engine has shut down, allow the fuel system to purge for ten minutes. This operating fuel system contains high pressure. Exposure to high pressure fuel can result in personal injury.

3500 Common Rail High-Pressure Rail - Safety Procedure

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Do not loosen any high pressure fuel lines when the engine is running. The high pressure in the fuel lines can cause personal injury or death. Wait 60 seconds after the engine has stopped to allow pressure to purge before any service or repair is performed on the engine fuel lines.

1. Before servicing the common rail fuel system on 3500 Tier 4 Final Engines, fuel that is under high pressure must be vented.

   Note: Fuel will vent into the double wall system when performing this process and remain there. Fuel purge from this system is not required.

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   Illustration 1	g06028905
   (1) End plug

2. Slowly loosen end plug (1) in the last high-pressure accumulator on either side of the engine. Make one full turn and wait for 30 seconds.

3. Verify that the fuel rail pressure is below 2 MPa (290 psi) using Cat^® Electronic Technician (ET) or CANape prior to performing any fuel system service.

4. Perform the required fuel system service.

5. Upon completion of the service, retighten the end plug to 60 ± 3 N·m (44 ± 2 lb ft). Failure to tighten the end plug will cause the fuel system to perform incorrectly.

3500 High-Pressure Common Rail - Cleanliness

Follow the suggestions below to prevent contamination of the fuel system and related components during the removal and installation procedure.

• Cap and/or plug the high-pressure fuel lines, junction block, and accumulator ports using 9U-7078 Tapered Cap/Plug.

• During service, immediately cap and/or plug all openings.

• Store parts in sealed, clean bags until the part is ready for installation.

• Do not remove caps and/or plugs until parts ready for installation on the engine.

High-Pressure Fuel System Components

Illustration 2	g06028998
(1) Accumulator lines (2) Fuel line clamps (3) Cross-over fuel lines and unions (4) High-pressure pump fuel line (5) Junction block (6) Junction block to accumulator quill high-pressure fuel line (7) High-pressure accumulator (8) Fuel injector

3500 Common Rail Fuel Flow Path

Illustration 3	g06029242

1. Fuel flows from the high-pressure fuel pump to the junction block.

2. Fuel flow is distributed to each cylinder bank through high-pressure fuel lines.

3. Fuel is delivered to fuel injectors through the high-pressure fuel lines and accumulators.

High-Pressure Accumulator Removal and Installation

Prior to removal of any high-pressure components, ensure that the proper caps are available to protect the component sealing surfaces to prevent intrusion of debris. Prior to installation of new components, verify that the components were shipped properly with all the openings capped and sealed. Do not remove the caps from the components until the parts are ready for installation. Whenever servicing and/or replacing parts, use caps to protect the components.

The high-pressure components connecting the high-pressure fuel pump to the injectors are reusable if care is taken to protect the sealing surfaces. Carefully inspect joints during assembly to ensure that foreign material is not present in the joints. The modular high-pressure accumulators and quills that connect to the injectors are also reusable.

Note: Use proper protective caps and/or plugs to cap fuel lines, fittings, ports, and any openings on the fuel system to prevent contamination. Use clean latex gloves when handling cleaned components.

Removal

1. Prior to loosening any high-pressure joints, use compressed air to remove any external debris from around the accumulator tube bore in the cylinder head.

2. Mark the high-pressure lines and accumulators with the parts location, so that the parts can be reinstalled at the same location.

3. Remove the high-pressure line clamp bolts and line clamps from the high-pressure lines connected to the accumulators.

   Note: Line clamps may need to be removed from the end of the high-pressure crossover line to allow the accumulator removal at cylinder #1. Removing the crossover line is not necessary.

4. Break open the joints between the accumulator lines and the accumulators.

5. Follow the steps below to ensure that the high-pressure fuel system does not become contaminated.

   1. Plug the open ports on the accumulators and quills with the 9U-7078 Tapered Caps/Plugs.

   2. Cap the ends of the high-pressure fuel lines with the 9U-7078 Tapered Caps/Plugs.

   3. Place the accumulators in a new, clean ziplock bag.

6. Remove the nuts from the accumulator to stud bolt joints outside the accumulator clamp. Retain the nuts for reuse during assembly.

   Note: Do not remove the studs from the cylinder heads.

7. Pull the accumulators slowly out of the cylinder heads. If prying is required, ensure that the pry-bar only contacts the surface underneath the accumulator clamp.

   Note: Fuel may come out of the accumulator bore in the cylinder head during removal.

8. Follow the steps below to ensure that the high-pressure fuel system does not get contaminated.

   1. If necessary, remove any rust scale from the outer rim of the accumulator bore using an 1U-5512 Abrasive Material or 8T-7765 Surface Reconditioning Pad.

      Note: The surface does not need to be polished and cleaning of rust should be done carefully.

   2. Remove any remaining debris from the outer edge of the accumulator bore using a new lint-free towel moistened with brake cleaner.

   3. Plug the open accumulator bores in the cylinder heads using the 276-0754 Plug Caps.

   4. Cap the bottom of the accumulator with the caps that are provided.

   5. Place the accumulators in a new, clean ziplock bag.

9. If replacing the accumulator at either cylinder 11 or 12, ensure that a new end plug and ball are available.

   Note: Reuse of the end plug and/or ball in the accumulator is not recommended.

10. If removing the accumulator at either cylinder 11 or 12 for inspection only, do not remove the high-pressure end plug.
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    Illustration 4	g06029330
    (1) Old 443-2970 Stud

11. Remove and discard the accumulator stud bolts (1) from the cylinder heads.

Installation

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Illustration 5	g06094089
(1) Old 443-2970 Stud (2) New 494-7086 Stud

1. Install the new accumulator studs (2).

   Tighten each new accumulator stud bolt to 47 N·m (35 lb ft), then turn the stud an additional 20 to 35 degrees.

   Note: An extra deep 5/8 inch socket will be required. A Snap-on SIM-L200 is recommended.

2. Remove the accumulators from the bags.

3. Remove the accumulator end caps and port caps.

4. Remove the accumulator port caps from the cylinder heads.
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   Illustration 6	g06094254
   (3) Accumulator o-ring seal (4) Accumulator

5. Lubricate accumulator o-ring seal (3) with clean, unused engine oil.
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   Illustration 7	g06094193
   (4) Accumulator

6. Install accumulator (4) over the previously install accumulator studs until the o-ring seal contacts the cylinder head.
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   Illustration 8	g06094263
   (5) Old Spherical washers 384-5541 Washer (6) New Spherical washers 494-6542 Washer

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   Illustration 9	g06094260
   (6) New spherical washers (7) Nuts

7. Install the new spherical washers (6) and the previously removed nuts by hand.

   Note: The spherical end of the washer must seat against accumulator clamp cone.

   Note: Do not push the accumulator in by hand. Pushing by hand could lead to damage of the accumulator tip which can result in a fuel leak.

8. Use one of the nuts (7) to draw the accumulator into the cylinder head until the accumulator bottoms out, contacting the injector. Do not completely tighten the nut used to draw the accumulator. Loosen the nut used to draw in the accumulator by one full turn.

9. Prepare the high-pressure fuel line for assembly.
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   Illustration 10	g06029402
   (8) Sealing band (good condition) - Reusable (9) Scratches that are not on the sealing band - Reusable (10) Scratches that are on the sealing band - Not reusable

   1. Check the condition of the line end sealing surfaces.

      Note: If the o-ring seals at the end nuts or the sealing surface are damaged, do not use the line.

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   Illustration 11	g06029404
   (11) Fuel line o-ring seal (12) Line threads (13) Nut collar (14) High-pressure fuel line nut

10. Lubricate fuel line o-ring seal (11), high-pressure line threads (12), and nut collar (13) with clean unused engine oil.
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    Illustration 12	g06029415
    (14) High-pressure fuel line nut

11. Install the high-pressure line nut onto the accumulator and hand tighten.

    Note: Do not tighten the line nut completely.

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    Illustration 13	g06029412
    (15) High-pressure fuel line clamp (16) Bolt

12. Install line clamp (15) and bolt (16) on the high-pressure line hand tight. The line clamp will help align the fuel line during tightening.

13. Tighten the high-pressure line nuts (14) at each cylinder, to a torque of 38 N·m (28 lb ft) using a 1–1/16 in or 27 mm crow foot wrench.

14. Tighten the high-pressure line nuts (14) at each cylinder, to a final torque of 100 N·m (74 lb ft) using a 1–1/16 in or 27 mm crow foot wrench.
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    Illustration 14	g06094580

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    Illustration 15	g06096195
    Properly tightened nuts

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    Illustration 16	g06096213
    Improperly tightened nuts

15. Tighten the accumulator nuts (7) alternately, 90 degrees at a time, to a final torque of 35 N·m (26 lb ft).

    Note: Do not let the stud bolts contact the ID of the bolt holes in the accumulator clamp.

16. Tighten the high-pressure clamp bolts to 47 N·m (35 lb ft).
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    Illustration 17	g06029436
    (17) Ball (18) End Plug (19) O-ring seal

17. Torque the existing end plugs (18) of the accumulators at cylinder 11 and 12, to 60 N·m (44 lb ft).

    If installing a new accumulators at cylinder 11 or 12, place a new ball (17) and new end plug (18) against the mating cone in the inlet port and hand tighten. Ensure that the ball seats properly on the mating cone. Torque the end plug (18) to 60 N·m (44 lb ft).

    Note: Lubricate the new o-ring seal (19) on the end plug with clean, unused engine oil.