An Improved Assembly Procedure for Hammer Power Group Is Now Available for Certain H55E and H55ES Hydraulic Hammers {5077, 6333, 7555} Caterpillar

Hammer

H55E S (S/N: 3X91-UP)

An improved assembly procedure for the hammer power group is now used on the machines listed above. The process improvement helps to ensure that the membrane is not damaged upon installation into the front head.

The Hydraulic Hammer - Assemble section of UENR4751 has been updated

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Illustration 1	g06039422

Note: Install the U-cup seal and the wiper seal with the lips facing opposite each other.

1. Apply clean hydraulic oil to the inside of the membrane (2).

   Install membrane (2) onto sleeve assembly (1). Apply clean hydraulic oil to seals (3) Install seals (3) into sleeve assembly (1).

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   Illustration 2	g06038935

2. Use a suitable lifting device to reposition the head assembly as shown. Refer to Table 2 for the approximate weight of the head assembly. Apply clean hydraulic oil to the outside of the sleeve assembly (1). Install sleeve assembly (1) into the head assembly.

   Note: Damage may occur to membrane (2) if sleeve assembly (1) is not seated properly into the head assembly.

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   Table 2

   Sales Model	Head Assembly Approximate Weight
   H55E	45 kg (99 lb)

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   Illustration 3	g06039366

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   Illustration 4	g06039374

   Note: Install U-cup seals with the lips of the seals facing opposite each other.

3. Apply clean hydraulic oil to the outside of piston (4).

   Install piston (4).

   Note: Install U-cup seals with the lips of the seals facing one another.

4. Install bushing (4A).
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   Illustration 5	g06039429

   Note: Install U-cup seals with the lips of the seals facing opposite each other.

5. Apply clean hydraulic oil to seals (6). Install seals (6) into seal carrier (5).
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   Illustration 6	g06038950

6. Install seal carrier (5) on the head assembly. Fill lifting eye hole of piston (4) with clean hydraulic oil.
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   Illustration 7	g06039440

7. Install valve body (9).

   Note: Make sure valve body (9) is completely seated against the head assembly before bolts (7) are installed. Damage may occur if Tooling (A) gets into the head assembly.

8. Apply Tooling (A) to shoulder of bolts (7). Install bolts (7). Tighten bolts (7) to a torque of 250 N·m (184 lb ft) in a cross pattern. Tighten bolts (7) in a cross pattern to a final torque of 800 N·m (590 lb ft). Apply sealant on threads and light oil on O-ring seal on plug (8). Install plug (8) and the O-ring seal.

   Note: Valve body (9) must be installed evenly onto the head assembly. Damage may occur to membrane (2) if the assembly is not completed properly.

9. Charge the low-pressure valve body. Refer to Testing and Adjusting, "Charging the Valve Body with Nitrogen (Low Pressure)" for the correct charging procedures.
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   Illustration 8	g06039446

10. Install plug (10) and the O-ring seal. Tighten plug (10) to a torque of 155 ± 1 N·m (114 lb ft).
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    Illustration 9	g06039448

11. Install plug (11) and the O-ring seal. Charge the accumulator. Refer to Testing and Adjusting, "Hydraulic Accumulator (High Pressure) - Test and Charge"for the correct charging procedure.
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    Illustration 10	g06039452

12. Install plug (12) and the O-ring seal. Tighten plug (12) to a torque of 155 ± 1 N·m (114 lb ft).