How should I control subcontracted infrastructure?

[somashekar]

WEll, I went with purchasing manager, he was agreed to amend the PO (we don't have a contract) to request supplier provide records of maintenance and replace the unit when we have issues, we are ISO 9000, I think I will raise it as an OFI.

Thanks for your help and guidance,

That is good Anerol. Just remember that suppliers records of maintenance is not your objective but the uninturrupted service of the crane truck is. What ever steps or controls you exercise including the suppliers maintenance records must finally ensure that your objective and requirement is met.
Approach this as a process interaction between Clause 6.3 (Infrastructure) and Clause 7.4 (Purchasing) with Clause 4.1, the outsourced process control part.