As per your question, you have already a damaged hard drive. So, as per my recommendation, it would be useless to clone this damaged hard drive data and store it on external drive. Also, if you have some very important files stored on this damaged hard drive, then you need to try a data recovery software to Recovers all your files and folders.

Imp. Note: If you already have data backup available, then simply restore it without spending money on buying a data recovery program.