Starter question

I have a old 1967 977k and the solenoid went out, when I was changing it the bolt that sits right behind it that has the copper strap L bracket that connects it to the starter broke free and just free spins now. I hooked everything back up and 99% sure I have it all hooked up the same way from what I remeber and looking at diagrams the past few days to double check. But when I try and start it now sparks fly from the negitive terminal and actually melt the post a little. I called my local Cat place but they wasn't sure what that does or if there was anything connected to it or maybe just grounds the 2 together. I looked at diagrams and it doesn't look to have anything connected but it says there is a bushing between it and the case. My thinking is its not getting a good ground because it's free spinning now, but any information on how to fix this or if it maybe my problem would be great. If this isn't my problem or if anyone has anything else I can check I would love any input. I didn't take the starter off to change it. I have the battery wire new thick cable someone ran big post battery side, a wire from the harness on the S small post, the ground from starter bolt to the small G post, and a wire from the starter switch ran to the big post positive battery side terminal. I will see if it will let me add a picture of the diagram I have.