797F and 797F XQ Off-Highway Trucks Machine Systems Caterpillar

Removal Procedure

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Personal injury can result from hot oil or hot components. At operating temperature, oil is hot and under pressure. Hot oil can cause burns. Remove the fill cap only when the engine is stopped, and the fill cap is cool enough to touch with your bare hand. Do not allow hot oil or components to contact skin.

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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

1. Release the system pressure. Refer to Operation and Maintenance Manual, "System Pressure Release".

2. Drain the hydraulic tank into a suitable container for storage or disposal. Refer to Operation and Maintenance Manual, "Steering Tank Oil - Change".
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   Illustration 1	g06206484

3. Disconnect hose assembly (1) and grease hose assembly (2). Repeat the same for the opposite end of the cylinder.

4. Remove retaining ring (3) to remove plug (4).
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   Illustration 2	g06223574
   Typical Example

5. Loosen the clamp and remove the cap.
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   Illustration 3	g06206532

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   Illustration 4	g06206485

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   Illustration 5	g06206488

6. Loosen two setscrews (8).

7. Loosen each jack bolt (7) 45 degrees following a one round circular pattern.

8. Loosen each jack bolt (7) 90 degrees in a circular pattern.

9. Continue loosening 90 degrees for third and successive rounds until all jack bolts (7) are loose.

10. Use Tooling (A) to retain ball stud (5) while nut assembly (6) is loosened.

11. Remove nut assembly (6).
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    Illustration 6	g06206490

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    Illustration 7	g06206491
    Typical Example

12. Use Tooling (B) to remove ball stud (5). Refer to M0080743Tool Operating Manual, "Hammer Group" and , M0083627Tool Operating Manual, "Hydraulic Power Unit" for the correct procedure to remove ball stud (5).
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    Illustration 8	g06206492

13. Remove clips (9) and cover (10). Disconnect harness assembly (11) and remove the connecting hardware.
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    Illustration 9	g06206497

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    Illustration 10	g06206499

14. Use Tooling (D) to support steering cylinder (12). Attach Tooling (C) and a suitable lifting device to remove steering cylinder (12). The weight of steering cylinder (12) is approximately 329 kg (725 lb).
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    Illustration 11	g06206535

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    Illustration 12	g06206500

15. Use Tooling (A) to retain pin (13) while nut assembly (14) is loosened.

16. Repeat Step 4 through Step 11 to remove nut assembly (14).
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    Illustration 13	g06206490

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    Illustration 14	g06206506
    Typical Example

17. Use Tooling (B) to remove pin (13). Refer to , M0080743Tool Operating Manual, "Hammer Group" and , M0083627Tool Operating Manual, "Hydraulic Power Unit" for the correct procedure to remove pin (13).
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    Illustration 15	g06206515

18. Remove steering cylinder (12).
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    Illustration 16	g06206537

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    Illustration 17	g06209324

19. Use Tooling (F) to remove spherical bearing race (15) from ball stud (5). Refer to Tool Operating Manual, M0069418 for additional information on using Tooling (F).
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    Illustration 18	g06206530

20. Remove shims (16), spacer (17), retaining ring (18), bearing (19), and spacer (20) from steering cylinder (12).

Sensor Removal Procedure

Note: Cleanliness is an important factor. Before the disassembly procedure, the exterior of the component should be thoroughly cleaned. This will help to prevent dirt from entering the internal mechanism.

Note: Put identification marks on all lines, on all hoses, on all wires, and on all tubes for installation purposes. Plug all lines, hoses, and tubes. This helps to prevent fluid loss and this helps to keep contaminants from entering the system.

Note: The Illustrations that are shown in the following Steps demonstrate the correct removal procedure for the sensor assembly, and these Illustrations may not represent the exact cylinder that is on your machine.

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Illustration 19	g01151971

1. Remove bolts (2) and cover (1).
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   Illustration 20	g01151970

2. Remove connector assembly (3) and sleeve (4) from the harness assembly.

3. Remove plate (5) and grommet (6).
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   Illustration 21	g06210288

4. Install Tooling (A) to sensor assembly (7).
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   Illustration 22	g01151955

5. Remove screw (8) and discard screw (8).
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   Illustration 23	g01152067

6. Remove sensor assembly (7).

7. Remove O-ring seal (9) and backup ring (10) from sensor assembly (7).

   Note: For pistons that are retained with a nut, refer to the following instructions for the removal of the magnet.

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   Illustration 24	g01154825

8. Remove retainer (11) and magnet (12) from carrier (13).

9. Remove carrier (13) from rod (14).

   Note: For pistons that are retained with a bolt, refer to the following instructions for the removal of the magnet.

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   Illustration 25	g01154827

10. Remove retainer (15) and magnet (16) from carrier (17).

11. Remove carrier (17) from bolt (18).

Sensor Installation Procedure

Note: Cleanliness is an important factor. Before assembly, all parts should be thoroughly cleaned in cleaning fluid. Allow the parts to air dry. Wiping cloths or rags should not be used to dry parts. Lint may be deposited on the parts which may cause later trouble. Inspect all parts. If any parts are worn or damaged, use new parts for replacement.

Note: The Illustrations that are shown in the following Steps demonstrate the correct installation procedure for the sensor assembly, and these Illustrations may not represent the exact cylinder that is on your machine.

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Illustration 26	g01152067

1. Lubricate backup ring (10) and O-ring seal (9) with the lubricant that is being sealed. Install backup ring (10) and O-ring seal (9) on sensor assembly (7).

   Note: Install backup ring (10) so that the split in backup ring (10) is in alignment with the slotted notch on the side of sensor assembly (7).

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   Illustration 27	g06210289

2. Assemble Tooling (B), as shown. Refer to Tool Operating Manual, NEHS0935.
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   Illustration 28	g06210291

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   Illustration 29	g06210295

3. Install sensor assembly (7) into Tooling (B).

4. Slide Tooling (C) over sensor assembly (7) until Tooling (C) has cleared the dimple in the side of sensor assembly (7), as shown.

   Note: If Tooling (C) is installed to the point which exposes the O-ring seal on sensor assembly (7), continue pulling sensor assembly (7) through Tooling (C) and repeat Steps 3 and 4. This will help prevent cutting the O-ring seal with Tooling (C).

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   Illustration 30	g01151972

5. Install sleeve (4) over the harness assembly.
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   Illustration 31	g06210297

6. Start by threading Tooling (D) through the wire passage of the cylinder. Continue threading Tooling (D) through the cylinder and secure Tooling (D) to the wires of sensor assembly (7), as shown.
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   Illustration 32	g06210299

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   Illustration 33	g06210301

7. With the help of another person, use Tooling (B) and Tooling (D) to guide the sensor assembly into position.

   Note: Use the alignment marks on Tooling (B) to ensure proper alignment of the sensor assembly into the counterbore. The sensor assembly should be installed with the alignment marks that are found on Tooling (B) toward the top, or in line with the wire passage in the cap if the wire passage is not in a vertical position.

8. Use Tooling (B) to push the sensor assembly into the counterbore until the pin engages the slot on the side of the sensor assembly. Make sure that the sensor assembly has engaged the counterbore correctly. Gently try to rotate Tooling (B) in both directions to ensure proper engagement of the sensor assembly.

9. Use a suitable mallet and Tooling (B) to tap the sensor assembly into the counterbore until the sensor assembly rests against the face of the counterbore.
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   Illustration 34	g01151955

10. Apply Tooling (E) to set screw (8). Install set screw (8). Tighten set screw (8) to a torque of 25 ± 6 N·m (18 ± 4 lb ft).
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    Illustration 35	g01151970

11. Install grommet (6).

12. Apply Tooling (F) to the mating surface of plate (5) and install plate (5).

13. Install sleeve (4) and connector assembly (3).
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    Illustration 36	g01151971

14. Install cover (1) and bolts (2).

    Note: For pistons that are retained with a nut, refer to the following instructions for the installation of the magnet.

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    Illustration 37	g01154825

15. Apply Tooling (G) to the threads of carrier (13) and install carrier (13) into rod (14). Tighten carrier (13) to a torque of 35 ± 5 N·m (26 ± 4 lb ft).

16. Install magnet (12) into carrier (13).

17. Apply Tooling (G) to retainer (11) and install retainer (11) into carrier (13). Tighten retainer (11) to a torque of 35 ± 5 N·m (26 ± 4 lb ft).

    Note: For pistons that are retained with a bolt, refer to the following instructions for the installation of the magnet.

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    Illustration 38	g01154827

18. Apply Tooling (G) to the threads of carrier (17) and install carrier (17) into bolt (18). Tighten carrier (17) to a torque of 35 ± 5 N·m (26 ± 4 lb ft).

19. Install magnet (16) into carrier (17).

20. Apply Tooling (G) to the threads of retainer (15) and install retainer (15) into carrier (17). Tighten retainer (15) to a torque of 35 ± 5 N·m (26 ± 4 lb ft).

Ball Stud Inspection

Note: Cleanliness is an important factor. Before the removal procedure, the exterior of the component should be cleaned thoroughly to prevent dirt from entering the internal mechanism.

Note: Use a known damaged ball stud and a new ball stud as baselines.

Note: The following Steps will help determine the condition of the ball studs. These Steps provide instructions for the ultrasonic inspection of the steering cylinder and steering linkage ball studs. These instructions provide a means of inspecting for cracks without removing the ball studs from the machine. This procedure is not a destructive test. Perform this procedure while the ball stud is still in the steering arm or in the steering box. The recommended interval for this procedure is every 1000 service hours unless an inspection interval has been established for your particular application.

Note: The recommended replacement interval for the steering cylinder and steering linkage ball studs is between 12000 operating hours and 15000 operating hours or at the planned component rebuild of the steering cylinder. The replacement interval will depend on the following conditions: haul road condition, length of hauls, number of turns per cycle, load, and grade of the haul road.

Note: Inspect the condition of the tapered steering bore whenever a ball stud is replaced. Refer to Reuse and Salvage Guideline, SEBF8271, "Salvage of Steering Arm and Steering Arm (T-Bar) Tapers on 785, 789, 793, and 797 Off-Highway Trucks" to determine whether the tapered bore can be reused or machined to an oversized dimension.

Note: The 797B and 797F Off-Highway Trucks do not have an oversized bore.

Note: If the tapered bore is out of the specification and the tapered bore can still be salvaged, then an oversize ball stud may be used. If the taper is too far out of the specification, then an oversize ball stud cannot be used. In this case, either the steering arm or the steering box must be scrapped and replaced.

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Illustration 39	g00842904

1. Use a wire brush or use a scraper to clean the end of the ball stud thoroughly. A clean surface ensures a good seal with the transducer.
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   Table 5

   Critical Dimensions of Ball Studs
   Sales Model	Pt. No. of Ball Stud	A	B	C	D	E	F
   784/ 785	8X-9619	273 mm (10.7 inch)	188.283 mm (7.4127 inch)	25.9 mm (1.02 inch)	53 mm (2.1 inch)	53.75 mm (2.116 inch)	82.55 mm (3.250 inch)
   789	8X-9620	295 mm (11.6 inch)	210.283 mm (8.2788 inch)	25.9 mm (1.02 inch)	53 mm (2.1 inch)	53.75 mm (2.116 inch)	82.55 mm (3.250 inch)
   793	8X-9620	295 mm (11.6 inch)	210.283 mm (8.2788 inch)	25.9 mm (1.02 inch)	53 mm (2.1 inch)	53.75 mm (2.116 inch)	82.55 mm (3.250 inch)
   797	156-8136	295 mm (11.6 inch)	210.283 mm (8.2788 inch)	25.9 mm (1.02 inch)	53 mm (2.1 inch)	53.75 mm (2.116 inch)	82.55 mm (3.250 inch)
   797B 797F	192-5702	341 mm (13.4 inch)	225.006 mm (8.8585 inch)	25.9 mm (1.02 inch)	80.26 mm (3.160)	79.53 mm (3.13 inch)	109.73 mm (4.320 inch)

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   Illustration 40	g00843601
   (1) Gel compound (2) Display screen (3) Krautkramer Branson USN 52 (4) Transducer

2. Apply standard gel compound to the transducer and to the end of the ball stud to ensure proper contact with the transducer.

3. Set the gate at 20 percent of the screen height.

4. Use a 2.25 MHz - 5Mhz straight beam transducer. The diameter of the transducer should measure 12.7 mm (0.5 inch) to 25.4 mm (1.0 inch). The area of concern is dimension (B) for this type of defect.

5. Apply the transducer to the threaded end of the ball stud.

6. Use the range key to move the reflected signal to "9" on the display screen. Keep the signal at "9" on the Display screen. Adjust the reflected signal for each ball stud to 100 percent of the screen height to ensure that the surface is the opposite end of the ball stud and that the surface is not the bottom of the drilled holes.

   Note: Drilled holes will reflect the signal.

7. Set the gate to 20 percent of the screen height.
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   Illustration 41	g00843670
   (B) Interruptions that are in this area will appear between the 0 grid mark and the 6.4 grid mark. (C) Interruptions that are in this area will appear between the 8 grid mark and the 9 grid mark. (G) Interruptions that are in this area will appear between the 6.5 grid mark and the 8 grid mark. (H) Cracks that are in this area CAN NOT be detected.

8. Slowly move the transducer over all surfaces of the end of the ball stud.

   Note: An indication from approximately 0 to 6.4 grid marks on the display screen indicates a damaged ball stud. A complete loss of the reflected signal may also indicate a damaged ball stud.

   Note: The area of concern (B) should occur approximately between 0 grid marks and 6.4 grid marks on the display screen. Reflected signals from the drilled holes should occur approximately between 8 grid marks and 9 grid marks on the display screen.

   Note: Although the ultrasonic beam spreads slightly, cracks that are in Area (H) CAN NOT be detected.

9. Identify the ball stud as an acceptable ball stud or as a damaged ball stud.

10. Document the following information.

    • Date of inspection

    • Serial number of the inspected truck

    • Part number of the inspected ball studs

    • Number of inspected ball studs

    • Number of ball studs that were damaged per truck

    • Initial of operator that performed the inspection

    • Any corrective action that was taken

Disassembly and Assembly Information

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Illustration 42	g06210470

1. Apply Tooling (B) to the threads of locknut (1). Tighten locknut (1) to a torque of 6000 ± 500 N.m (4425 ± 369 lb ft).

2. Apply Tooling (D) to the threads of retainer (2). Tighten retainer (2) to a torque of 35 ± 5 N.m (26 ± 4 lb ft).

3. Apply Tooling (F) to connector plate (3) prior to assembly.

4. Lubricate sealing lips (4) and (5) with the lubricant that is being sealed.

5. Apply Tooling (E) to the wiper groove prior to assembly.

6. Apply Tooling (E) to wiper seals (6) and (7) prior to assembly.

7. Tighten bolt (8) to a torque of 47 ± 9 N.m (35 ± 7 lb ft).

8. Apply Tooling (D) to the threads of setscrew (9). Tighten setscrew (9) to a torque of 25 ± 6 N.m (221 ± 53 lb in).

9. Tighten bolts (10) to a torque of 900 ± 100 N·m (664 ± 74 lb ft).

Installation Procedure

Note: Cleanliness is an important factor. Before the installation procedure, the exterior of the component should be thoroughly cleaned. This will help to prevent dirt from entering the internal mechanism.

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Illustration 43	g06226599

1. Use Tooling (D) to support steering cylinder (12). Attach Tooling (C) and a suitable lifting device to remove steering cylinder (12). The weight of steering cylinder (12) is approximately 329 kg (725 lb).
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   Illustration 44	g06206530

2. Install spacer (20), bearing (19), retaining ring (18), spacer (17), and shims (16) into steering cylinder (12).
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   Illustration 45	g06206537

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   Illustration 46	g06209324

3. Apply Tooling (E) onto the threads and the taper of pin (13) and ball stud (5).

4. Use Tooling (F) to install ball stud (5) and spherical bearing race (15) into the steering cylinder. Refer to Tool Operating Manual, M0069418 for additional information on using Tooling (F). Repeat the same for the other end of the cylinder.
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   Illustration 47	g06206500

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   Illustration 48	g06226685

5. Ensure that the mating surfaces and spot faces are clean and free of paint. Apply Tooling (E) on the washer faces under all nut assemblies (14) and all jack bolt (14B) threads.

6. Ensure that all jack bolts (14B) are flush or recessed with the bottom face of nut assembly (14).

7. Spin on nut assembly (14) by hand until nut assembly (14) seats against the washer or bottoms out.

8. Back off nut assembly (14) by a half turn but no more than 3/4 a turn to provide a gap between nut assembly (14) and the washer.
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   Illustration 49	g06223591
   Typical Example

9. Use Tooling (G) and Tooling (H) to tighten jack bolts (14B).

10. Tighten jackbolts (14B) in a 90 degree pattern to a torque of 60 ± 6 N·m (44 ± 4 lb ft).

11. Again, tighten jackbolts (14B) in a 90 degree pattern to a torque of 118 N.m (87 lb ft).

12. Check and confirm the torque values after 10 to 15 hours of operation and reapply the torque in Step 22, if necessary.
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    Illustration 50	g06206492

13. Install the connecting hardware. Connect harness assembly (11). Install cover (10) and clips (9).
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    Illustration 51	g06226695
    Typical Example

14. Tighten two setscrews (14A) to a torque of 20 N.m (177 lb in).
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    Illustration 52	g06223574
    Typical Example

15. Install the cap over nut assembly (14) and secure with the hose clamp as shown in the Illustration above.
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    Illustration 53	g06206485

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    Illustration 54	g06206488

16. Ensure that the mating surfaces and spot faces are clean and free of paint. Apply Tooling (E) on the washer faces under all nut assemblies (6) and all jack bolt (7) threads.

17. Ensure that all jack bolts (7) are flush or recessed with the bottom face of nut assembly (6).

18. Spin on nut assembly (6) by hand until nut assembly (6) seats against the washer or bottoms out.

19. Back off nut assembly (6) by a half turn but no more than 3/4 a turn to provide a gap between nut assembly (6) and the washer.
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    Illustration 55	g06223591
    Typical Example

20. Use Tooling (G) and Tooling (H) to tighten jack bolts (7).

21. Tighten jack bolts (7) in a 90 degree pattern to a torque of 60 ± 6 N·m (44 ± 4 lb ft).

22. Again, tighten jack bolts (7) in a 90 degree pattern to a torque of 118 N.m (87 lb ft).

23. Check and confirm the torque values after 10 to 15 hours of operation and reapply the torque in Step 22, if necessary.
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    Illustration 56	g06223592
    Typical Example

24. Tighten two setscrews (8) to a torque of 20 N.m (177 lb in).
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    Illustration 57	g06223574
    Typical Example

25. Install the cap over nut assembly (6) and secure with the hose clamp as shown in the Illustration above.
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    Illustration 58	g06206484

26. Install plug (4) and retaining ring (3).

27. Connect grease hose assembly (2) and hose assembly (1). Repeat the same for the opposite end of the cylinder.

28. Fill the steering hydraulic tank with hydraulic oil to the correct level. Refer to Operation and Maintenance Manual, "Steering System Oil - Change" for the correct procedure.