| NOTICE |
|---|
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates. |
| Required Tools | ||
| Part Number | Description | Quantity |
| 6V-0028 | Wear Gauge | 1 |
Boom Chains
The chain extends the boom and the chain that retracts the boom must be cleaned and inspected. Also, the chains must be measured for wear. The chains must be lubricated after two years or every 3000 hours. In severe operating conditions, this service interval must be reduced.
Disassemble the chains from the boom. For disassembly and assembly procedures for the chains, refer to Disassembly and Assembly, RENR5192.
Check Condition
- Park the machine on level ground. Fully retract the boom and lower the boom.
- Remove the cover from the rear of the chassis.
- A limited inspection of the chains can be made through the rear of the boom. The boom extension chain can be inspected by fully extending the boom and looking on top of the intermediate section. If the chains are corroded, the chains must be removed from the boom for cleaning and a full inspection. If the chains require lubricant, the chain must be removed from the boom for cleaning and a full inspection.
Cleaning and Inspection
Use a suitable degreaser to thoroughly clean the chains. Remove all traces of dirt and grease and lay the chains on a clean bench for inspection.
Carefully inspect the full length of the chains for damage, and in particular check for the following possible damage:
- Cracked link plate or missing link plates
- Elongated holes in link plate
- Pins that are loose
- Pins with damaged heads
- Rust or corrosion on link plates
Mark the most noticeable worn section of each chain. This will usually be near the center of the chain.
Check and Adjust the Chain Tension
Refer to the Operation and Maintenance Manual, "Boom Chain Tension - Check/Adjust" for the correct procedure.
Measuring Chain Wear
Nominal pitch of the link pins equals 25.4 mm (1 inch).
Nominal height of the plate equals 24.1 mm (0.95 inch).
- Fully retract the boom. Position the boom horizontally.
- Extend the boom by 2 m (6 ft 7 inch) or extend the boom to the section of chain that most frequently passes over the boom extension chain pulley.
Do not retract the boom sections before you begin to measure the chains.
- Use a caliper in order to measure the height of inner plate (A) and the height of outer plate (A) over 15 pitches of the selected worn section of chain. If any plate for the chain shows a reduction in height of more that 5% wear, all chains must be replaced. Also, if the measurement is less than 22.89 mm (0.901 inch), all chains must be replaced.
 | |
| Illustration 1 | g00747739 |
- Use a 6V-0028 Wear Gauge in order to measure the chain between the 16 pin centers of the selected worn section (B). The nominal length of 16 pin centers is 381 mm (15 inch). If the measurement shows an elongation of more that 2%, all chains must be replaced. Also, if the measurement is greater than 388.6 mm (15.30 inch), all chains must be replaced.
Lubrication
Spray the full length of each chain on both sides with 1U-8266 Chain and Cable Lubricant. Ensure that the lubricant penetrates the working surfaces between the links and pins by articulating the chain as the spray is applied.
When the chains are assembled into the boom, lubricate the pins at the anchor points.
Ensure that the proper precautions are taken when you use pressurized containers and solvents. Also, use the proper protective equipment and clothing when you use pressurized containers and solvents.