Inspection of the Duo-cone Seal Gp{4050, 4051, 7561} Caterpillar

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Introduction

The special instruction will provide you with the process for inspecting the duo-cone seal gp on your machine. The duo-cone seal gp may need replaced.

Reference Information

Illustration 1	g02130953
(1) Gap (2) Housing ramp (3) Seal ramp (4) Flat (5) Spherical (6) Seal ring (7) Toric ring (8) Housing (A) Stationary side (B) Rotating side (C) Axis of rotation

Procedures to be Performed Before Disassembly

Note: Before you disassemble the wheel group, capture the information that follows.

Note: Some checks may not be applicable on all machines.

1. The duo-cone seal gp may start leaking if a machine has been idle for a long period. Run the machine for several days in order to reseat the seals. Clean the wheel group and clean the rim. Monitor the duo-cone seal gp for continued leaking. Replace the duo-cone seal gp if the duo-cone seal gp continues to leak.

2. Make sure that the oil reservoir for the hoist system and the brake system has the proper amount of oil. Make sure that the oil is not overfilled. Ensure that the axle oil level is at the correct level.

3. Check that the axle breather is operating correctly. Follow the appropriate service literature for cleaning and inspecting the breather.

4. Check for a history of overheating of the brake oil. If there has been a history of overheating, the rubber portion of the seal may have taken a compression set. Review the appropriate service literature in order to check for brake overheating. The brake oil may overheat or the axle oil may overheat. Make sure that the machine is configured correctly for the application or provide operator training in order to stop the warnings for overheating temperatures.

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Illustration 2	g02080253

5. Measure gap (A) in the cavity for the duo-cone seal gp before disassembling the axle in order to repair the wheel group. This measurement with the assembled height of the face can be used to determine the amount of load on the face of the seal.

6. Refer to the appropriate Disassembly and Assembly Manual.

Measure the Height of the Assembled Seal

Note: Measure the assembled height of the seal. You must take a measurement in four positions. The positions are located 90 degrees from each other on the seals for the inner and outer wheel if the machine contains two seals. The height measurements of the seal provide two critical pieces of information. Look for a ring seal that has slipped. Also look for a compression set in the ring seal if the height of the seal is below the normal assembled height. If one of the four measurements are off by more than 1 mm (0.039 inch), then the seal is slanted in the bore, which may be from assembly.

Note: If your machine has two seals per wheel group, then the height of the seals will need to be measured.

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Illustration 3	g02080374

1. The measurement should be taken from the face of the sealing ring to the face of the housing for the component. This measurement will give you distance (B) .

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Illustration 4	g02080375

2. Measure the assembled height of the seal in four positions that are separated by 90 degrees. Refer to Illustration 4. Refer to Special Instruction, SEHS8484, "Tool and Specification Chart for Conventional Duo-Cone Seal Groups" for the proper assembled height dimensions.

Perform Checks In Order To Find the Condition of the Sealing Ring

The following Illustrations show conditions of the sealing ring that will cause failures.

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Illustration 5	g02080495

1. The toric ring that is shown in Illustration 5 was not installed correctly. The toric ring was not fully seated onto the housing ramp for the seal during installation. This condition caused the toric ring to bulge.

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Illustration 6	g02080641

2. Illustration 6 shows a toric ring that was torn during operation of the machine. Inspect the positions of the toric rings relative to the seal and check the condition of the metal sealing face.

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Illustration 7	g02080696

3. The toric ring that is shown in Illustration 7 is twisted. The toric ring should be even all the way around when you compare the toric ring to the housing ramp. Draw a line on the sealing ring in order to determine if the sealing ring is twisted. Remove the sealing ring. Check the line in order to make sure that the line is even all the way around the toric ring. There will be waves in the line or the line will move if the toric ring was twisted.

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Illustration 8	g02080714
The seal (1) is in the correct location.

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Illustration 9	g02080715
The seal (1) is in the incorrect location.

4. The seal in Illustration 8 is allowed to roll the toric seal up the ramp of the seal for normal operation. The ring seal in Illustration 9 is not allowed to roll the toric seal up the ramp for the seal. The seal will feel hard.

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Illustration 10	g02080853

5. The toric ring in Illustration 10 has slipped during operation. The pad on the back of the metal ring has been imprinted into the sealing ring.

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Illustration 11	g02080875

6. The part number from the sealing ring was imprinted on toric seal (2) that is shown in Illustration 11. Toric seal (2) has also been compressed.

Check the Condition of the Metal Seal Ring

Illustration 12	g02080993

Illustration 13	g02080995

Check the condition of the metal sealing ring. Look for scoring of the metal face and grooves on the sealing band. Also, look for pieces that have been removed from the sealing band. Refer to Illustration 12. Refer to 13.

Illustration 14	g02081653

There are three reasons for scoring damage to the metal sealing rings. The causes are listed below:

• Debris may be located between the sealing surfaces. You will need to find the debris that scores the seal.

• Surface contact will cause fatigue. Check the type of oil that is used in the cavity for the duo-cone seal gp. Make sure that the sealing ring has not slipped. Make sure that the machine was not allowed to travel above the design parameters.

• Machines that are experiencing early hour failure will need to be checked. The machine may not be ran until the machine is broken in. the early hour failure usually occurs after a repair or after a rebuild. Lock the machine out of top gear for the first 10 to 50 hours. This procedure will allow the sealing ring to relax into the designed operating load for the face.

Illustration 15	g02081796
Location of the date of manufacture on the metal sealing ring

After all of the initial examinations of the seal are done, the seals will need to be marked. The mark will inform you of the location of the seal. Carefully remove the seals.

Note: If the face seal is scored, the outer diameter of the seal could be sharp. The proper safety precautions should be followed during the removal of the metal sealing ring.

Measurement of the Compression of the Toric Ring

The condition of the toric ring after disassembly is important. The toric ring should be round. Roll the toric ring between your fingers and feel for flat areas on the toric ring. If flat areas are found, then cut the toric ring and take a picture of the cross section of the toric ring. The flat areas are an indication of compression on the toric ring.

Illustration 16	g02081913

The toric rings that are shown in Illustration 16 have taken some compression set during operation. The cross section of the toric ring is egg shaped. The toric ring will have two flat spots. The flat spots will be opposite each other 180 degrees.

Illustration 17	g02081953
(A) 17.81 mm (0.701 inch) (B) 14.78 mm (0.582 inch)

The smallest measurement is 14.78 mm (0.582 inch) and the largest measurement is 17.81 mm (0.701 inch).

Note: Compression of a toric ring is typically caused by heat or age. Review the machines ECM or VIMS in order to obtain the warnings for the temperature of the brake or axle.

Additional References for the Duo-cone Seal Gp

Illustration 18	g02082053
The toric ring on the left has spun in the seal bore and the sealing ring has worn a flat spot into the seal.

The toric ring may have a flat area on the circumference of the toric ring. The flat spot may be caused by spinning in the housing and the seal may be worn away.

Illustration 19	g02082100
The seal on the left is burnt.

The toric ring may have taken a large heat cycle. The seal material will appear burned. The seal material will appear to be dried. The seal material will appear discolored. Identify the heat source. Reduce the heat. The source of heat is typically the service brakes. Operator training is recommended when the service brakes are at fault.

Illustration 20	g02082433

Illustration 20 shows a toric ring that has cracking. Look for these issues on the sealing ring.

Illustration 21	g02082437

Illustration 21 shows the toric ring with little pieces of material that are embedded into the toric ring.

Illustration 22	g02082438

A piece is removed from the toric ring in Illustration 22.