120M, 12M, 140M and 160M Motor Graders Caterpillar

Introduction

The following procedure is used in order to check the elongation of the drive chains.

It is important to check the chains inside the tandem drives for wear. Normal operation will cause the pins, links, and rollers in the chains to wear. The chart lists the maximum limits of chain wear for a given number of chain links. Elongation of the chain due to wear is considered normal. Elongation of 3% is normal for all motor graders. The chain should be replaced when the chain reaches the maximum allowable wear. This action will prevent possible damage that could be caused by a broken chain.

Note: A broken chain can wedge in the tandem housing. A wedged chain can damage the following items: sprockets, spindles and housings.

Check Preparation

Before you begin this procedure, refer to Testing and Adjusting, "Machine Preparation".

Reference: Refer to the Power Train Disassembly and Assembly, "Drive Chain - Remove".

1. Remove the Drive Chain from the motor grader.

Test Procedure

1. Inspect the chains. Replace the chains for the following conditions:

   • Cracks

   • Broken components

   • Deformation

   Note: If the chain does not pass the inspection, the entire chain must be replaced. Always replace both chains in a tandem housing at the same time. Do not splice a new section of chain on a worn section of chain. Worn chains will not engage the sprockets properly and increased damage to the sprocket may occur.

   Show/hide table

   Personal injury or death can result from improper lifting or blocking. When a hoist or jack is used to lift any part or component, stand clear of the area. Be sure the hoist or jack has the correct capacity to lift a component. Install blocks or stands before performance of any work under a heavy component. Approximate weights of the components are shown. Clean all surfaces where parts are to be installed.

2. Suspend the chain from the hoist.

3. Hang a suitable scale from the chain. The scale must be able to measure the chain tension that is listed in Table 1.

4. Fix the free end of the scale to the motor grader.

   Reference: Refer to the Operation and Maintenance Manual, "Lifting and Tying Down the Machine" for the proper lifting locations for a motor grader.

5. Apply the proper amount of chain tension. Refer to Table 1. Ensure that all of the slack is out of the chain before a measurement is taken.

6. Measure the number of chain links that are listed in Table 1.

7. The elongation of the chain must be less than the specification in Table 1.

   Note: If the elongation of the chain is not within specifications, the chain must be replaced. Replace the entire chain. Always replace both chains in a tandem housing at the same time. Do not splice a new section of chain on a worn section of chain. Worn chains will not engage the sprockets properly and increased damage to the sprocket may occur.

8. You may reuse the old chain if the chain passed the checks for chain wear. Otherwise install a new chain.

   Reference: Refer to the Power Train Disassembly and Assembly, "Drive Chain - Install".

Refer to the following table for the limits for chain wear.