My starter connection/wire corroded really bad. I know I have to replace the starter its self. Do I have to replace the whole battery cable assembly? Can just the starter portion be replaced?

 

Just the cable. and coat it with grease!

 

The whole cable assembly? Is it 1 big wire bundle or can i just buy the starter portion?

 

Why do you have to replace the starter if the cable is bad?

 

the starter rusted out too

 

I don't think so. Fenders rust out, floor boards rust out; if those are gone then maybe the starter is next.

If something is wrong with the starter, pull it and take it to an automotive electricial shop and have it repaired. If all that is wrong with the starter is that the connections on the outside are corroded try polishing them with some course sandpaper. The same goes for the termination of the main cable from the battery. Then, like was written above, coat the connections with grease to keep this from reoccurring.