As part of our 10,000km Undercarriage Service we pay particular attention to finding cracks in the chassis from fatigue. Cracks where the cross members meet the chassis rails can be common after 100,000km and can be gusseted to repair. Stress rails under the A-frame often have breaks however this is partly due to weld positions. Generally chassis systems from the mid 90’s onwards are a lot more robust and don’t suffer a huge amount of fatigue.
Cracks in spring hangers can be the most critical and need to be monitored, and sometimes gusseted.