307.5, 308, 308.5, 309, and 310 Mini Hydraulic Excavator Machine Systems Caterpillar

Installation Procedure

When the Duo-Cone Seals are installed and assembled, you must use the correct procedures. The Duo-Cone Seal may fail from one or more mistakes that are made during assembly or during installation of the seal components.

Reference: Special Instruction, SEHS8364, "Assembly and Installation of Conventional Duo-cone Seals"

Reference: Special Instruction, SEHS8484, "Tool and Specification Chart for Conventional Duo-Cone Seals"

Correct Assembly of Conventional Duo-Cone Seals

Illustration 1	g01092143

Assembly and Installation Procedure

Show/hide table

Avoid prolonged skin contact with isopropyl alcohol. Avoid breathing the vapors in enclosed areas without adequate ventilation and do not smoke. Isopropyl alcohol is flammable. Do not use near open flame, welding operations, or around heated surfaces exceeding 482°C (900°F).

1. Remove any film, dust, or other foreign matter from the following components:

   • Rubber toric ring (2)

   • Housing ramp (4)

   • Seal ring ramp (7)

   • Housing retaining lip (3)

   • Seal ring retaining lip (8)

   • Seal ring housing (5)

   Note: Seal rings have sharp edges. Protective gloves should be worn to prevent injury.

   Use the cleaning agents in Tooling (B) or use isopropyl alcohol or other approved cleaning agents. Use a clean lint free cloth for wiping. All components should be dry before proceeding.

   Note: Never permit oil to contact rubber toric ring (2), housing ramp , (4), or seal ring ramp (7) before both seal rings (1) are assembled in the final position.

   Show/hide table

   Illustration 2	g00534617

   Show/hide table

   Illustration 3	g00446488

2. Put rubber toric ring (2) on seal ring (1). Make sure that the rubber toric ring is positioned at the bottom of seal ring ramp (7). The rubber toric ring must rest against retaining lip (8). The rubber toric ring must be straight in the seal ring. The rubber toric ring must not be twisted.

   Note: Be careful when you are working on the rubber toric ring. Nicks, cuts, or scratches may cause leaks.

3. Refer to Special Instruction, SEHS8484, "Tool and Specification Chart for Conventional Duo-Cone Seals" to select the proper installation tool.
   Show/hide table

   Illustration 4	g00534621
   Use towels or a mat (A) that is made of foam to aid with installing the toric ring (2).

4. Install rubber toric ring (2) on seal ring (1) with installation tool (9). Lightly dampen the lower half of rubber toric ring (2) with an appropriate lubricant. Refer to the "Acceptable Lubricants for Assembly" section that is in this publication for additional information. Use the following techniques to dampen the rubber toric ring:

   • Wipe the seal with a lint free cloth.

   • Place towels or a mat that is made of foam at the bottom of a container. Soak the towels or the mat with the lubricant. Dip the rubber toric seal in the container.

   Note: Periodically inspect the installation tool for damage. If necessary, replace the installation tool.

   Show/hide table

   Illustration 5	g00534622

5. Make sure that the lower half of rubber toric ring (2) is still wet. Use installation tool (9) to position seal ring (1) and rubber toric ring (2) squarely against seal ring housing (5). Make sure that you use sudden pressure and even pressure when you press a toric ring that has a small diameter. Press rubber toric ring (2) under housing retaining lip (3) that is part of seal ring housing (5). Use the following steps to install a rubber toric ring that has a large diameter:

   • Push the rubber toric ring over the seal ring retaining lip on one side.

   • Tap the installation tool with a rubber mallet on the opposite side of the rubber toric ring. Tap until the rubber toric ring is past the seal ring retaining lip of the housing.
   Show/hide table

   Illustration 6	g01092154
   Tooling (A) ( B) Assembled height (10) Dial indicator (11) Collet assembly (12) Dial indicator base (plastic) (13) Contact point

6. Use Tooling (A) to check the assembled height (B) at four locations that are 90 degrees from each other. The difference in height must not exceed 1.0 mm (0.04 inch). Refer to Illustration 6.
   Show/hide table

   Illustration 7	g00446492

7. Do not adjust the seal ring (1) by pushing the seal ring or by pulling on the seal ring. Use installation tool (9) to push down on the seal.
   Show/hide table

   Illustration 8	g00446493

   Show/hide table

   Illustration 9	g00446494
   Examples of incorrect assembly

8. Rubber toric ring (2) may twist during installation if the seal is not wet or if there are burrs or fins on housing retaining lip (3) that is part of seal ring housing (5). Misalignments, twists, and bulges of the rubber toric ring will cause Duo-Cone Seal failures. If correct installation is not obvious, remove the toric ring from the housing and repeat the installation procedure.
   Show/hide table

   Illustration 10	g00446495

9. Wipe seal ring face (6) that is part of seal rings (1) by using a lint free cloth. No particles of any kind are permissible on the sealing surfaces. A small piece of paper from a paper towel can force apart the seal ring face, which will cause a leak.

   Note: Rubber toric ring (2) must never slip on the ramps of seal ring (1) or the ramps of seal ring housing (5). To prevent slippage, allow adequate time for evaporation of the lubricant before proceeding with the procedure. Once the rubber toric ring is correctly positioned, the rubber toric ring must roll only on the ramps.

   Show/hide table

   Illustration 11	g00534623

10. Apply a thin film of clean oil on the entire seal ring face of one or both seals. Use a lint free cloth or brush to distribute the oil evenly. Be careful not to get any oil on the rubber toric rings. Lubricate the seal faces by using the same oil that was used during assembly. Dye may have been used in the oil that was used during assembly. Use the same kind of oil without dye to lubricate the seal faces.
    Show/hide table

    Illustration 12	g00446497

11. Make sure that both seal ring housings (5) are in correct alignment and that the seal ring housings are concentric. Move the parts slowly and move the parts carefully toward each other.

    Note: Do not force the seal ring and the seal ring housing together in a sudden manner. The seal component could be scratched or the seal component could be broken if the components are slammed together.

12. Tighten the bolts after the components are in the correct position.

Acceptable Lubricants for Assembly

Show/hide table

Avoid prolonged skin contact with isopropyl alcohol. Avoid breathing the vapors in enclosed areas without adequate ventilation and do not smoke. Isopropyl alcohol is flammable. Do not use near open flame, welding operations, or around heated surfaces exceeding 482°C (900°F).

Note: Do not use any liquid that leaves an oil film. Do not use any liquid that does not evaporate quickly. All the guidelines for safety and all the guidelines for disposal must be followed when you use a flammable liquid. The following liquids are acceptable lubricants for assembly:

• Quaker Solvo Clean 68-0

• Houghto-Grind 60 CT

• Isopropyl alcohol

Some seal kits come with silicone toric rings. As an option to using liquid lubricants to install silicone toric rings, the rings can be chilled for easier installation. This will allow the toric ring to contract for easier installation.

If chilling is desired, Seals should be placed in a freezer for 5 minutes prior to installation. Temperature in the freezer should be between −40°C (−40°F) to −18°C (0°F). Contraction will be sufficient to allow installation. The seals should be allowed to warm to room temperature prior to further assembly.

Result of Incorrect Assembly

Illustration 13	g00446498

The slipping of the rubber toric ring on the housing ramp or on the seal ring ramp may result in uneven pressure on the seal face. Uneven pressure on the seal face causes galling, scoring, and leakage.

If the rubber toric ring slips at one location but not all the way around the seal ring, the toric ring will twist.

The twisted toric ring could be cocked. Seals that are cocked will cause uneven pressure on the seal face. Seals that are cocked may also cause possible galling, scoring, and leakage.

The twisted toric ring could oscillate when the ring is rotated. Seals that oscillate may allow dirt into the seal joint. This is caused by the pumping action that is created by the toric ring that is oscillating.

Illustration 14	g00446499

Illustration 14 shows a toric ring that is assembled incorrectly. The upper housing is stationary. The lower housing is rotating.

Illustration 15	g00446500

Illustration 15 shows that the same seal after the lower housing has rotated 180 degrees. In this position, there will be high pressure at Point (B) and at Point (X). These points of high pressure may result in galling of the toric rings. There will be low pressure at Point (A) and at Point (Y) which will result in possible leakage.