Welcome to HEF
@Wayne1963
A handbrake cable is not really a "major" job on a backhoe - However, the if the clevis pins are seized they can be difficult.
There are two different parkbrake set-ups on 580E, so, depending on the one you have, there is quite a difference.
Early models have the cable going to a cross-shaft on top of the transaxle.
If this is the type you have, there maybe other issues if it has not been used for a while.
Later models use a disc on the front of the transaxle.
Regardless of the type you have, you need to disconnect the cable from any actuating lever & then see if the cable is seized or if the problem is with the operating mechanisms.