My father left us for another woman in 1975, I was 5 years old then. He was a US Navy serviceman that time and is now a retired pensioner. We never received any form of support from him until today. My mother gave all her best to raise all 5 children by herself. She passed away in 1992. Can we file for an abandonment case against my father?

No. Abandonment (except in a very few states) is leaving a minor without adult supervision. You mean child support.

And you can't do that either. Your mother, not you, would have had to file. No doubt the statute of limitations has long since expired.

Were your parents divorced? If so, she should have had a "qualified domestic relations order" (or "QDRO") issued by the divorce court. That might affect his retirement benefits. Check if this happened.

"We never received any form of support from him until TODAY". What happened today? That was almost 40 years ago and you are 44. Certainly no child support.

I think 'until today' is what many people say who speak English as a second language when they mean 'right up through today.'
Most of us would just say 'we never received any support.'
Is that what you meant?

No, you can not file, if there was any case, the SOL has long ran out.

Was there ever a child support order though the court? If not, legally he did not owe any money. What effort did your mother do, to collect? How mamy times did she take him to court to collect money?

As a child, you may have a claim to his estate, when he passes away

As noted, abandonment is not an issue here. Nor can you file for child support at this late date. However, if your mother was awarded child support in the divorce or some other court proceeding and that support was never paid, your mother's estate might be able to go after him for unpaid support. But is mom died in 92, its probably too late for that.

It would help if you explain what happened today. Did something happen or did you just mean that you haven't received support right up until today.