Fault Phenomenon: CAT rotary drilling rig a periodic rumbling sound comes from the track while driving.

Troubleshooting Process:
– Checked bearing: carrier roller bearing raceway spalling.
– Checked lubrication: lubricating grease dried out.
– Checked seal: seal failed, water ingress.
– Checked load: overload.

Root Cause: The carrier roller bearing failed due to water and sand ingress from seal failure, leading to loss of lubrication.

Required Parts: Replace carrier roller assembly.