994D Wheel Loader Machine System Caterpillar

Assembly Procedure

Illustration 1	g03371051
Seal and Wear Band Orientation

When assembling a hydraulic cylinder, the piston seal must be oriented so that the step cut is at the bottom. The piston seal must be oriented 180° from the hydraulic cylinder ports (A) . The wear band gap should be oriented 45° to 90° in either direction from the seal step cut (B) or (C) .

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Illustration 2	g00584951

Note: Verify that all of the components of the lift cylinder are clean and free of foreign material prior to installation.

Note: Check all of the components for wear or damage. Replace the components, if necessary. Lubricate O-ring seals lightly with the lubricant that is being sealed.

1. Position cylinder assembly (4) in Tooling (A) for assembly.

2. If necessary, install two plugs (5) and the O-ring seals in rod assembly (11) and cylinder assembly (4) .

3. Install O-ring seal (12) , backup ring (13) , and O-ring seal (14) on head (10) .

4. Apply 4C-4032 Bearing Mount Compound to the groove for wiper seal (18) prior to the installation of wiper seal (18) . Install wiper seal (18) , U-cup seal (17) , and buffer seal (16) on head (10) . Lubricate the sealing lips of lip seal (18) , U-cup seal (17) , and buffer seal (16) prior to installation.

5. Install wear ring (15) on head (10) .

6. Temporarily install head (10) with six bolts (3) and two bolts (2) to cylinder assembly (4) . Tighten six bolts (3) and two bolts (2) by hand. Carefully install rod assembly (11) to head (10) and cylinder assembly (4) . Remove bolts (3) and (2) that install head (10) and rod assembly (11) to cylinder assembly (4) .

7. Install seal assembly (8) and two wear rings (7) on piston (9) .

8. Install piston (9) to rod assembly (11) . Lubricate the threads of six bolts (6) . Install six bolts (6) and the hard washers that hold piston (9) to rod assembly (11) . Tighten six bolts (6) to a torque of 3600 ± 400 N·m (2660 ± 295 lb ft).

9. Slide rod assembly (11) and head (10) into cylinder assembly (4) .

10. Install six bolts (3) , two bolts (2) , and the washers in order to connect head (10) to cylinder assembly (4) .

11. Fully extend the rod assembly. Tighten six bolts (3) and two bolts (2) to a torque of 1800 ± 200 N·m (1330 ± 150 lb ft).

End By: Install the lift cylinder. Refer to Disassembly and Assembly, "Lift Cylinder - Install".