The steering gear box fastening screws may be missing, fitted with incorrect extended screws or non-original screws have been installed that may be loose.

https://www.productsafety.gov.au/recall/daimler-truck-and-bus-australia-pacific-pty-ltd-mercedes-benz-bus-o500r-and-o500rs-my2019?fbclid=IwAR2JuX_YgIb5-V9cUonEo_COZvDLJg0Dy5xXxsFDnVqq9KGVFVqSKZGJC5g