Thank you for your question.
You have been told that he knows about you.
Going to his door can have a few different reactions.
You dad could welcome you and tell you to come in to talk and say you both have a lot of catching up to do, but he could also tell you that you should have not have come.
One of the best things to do is to write a letter letting him know that you would like too see him.
You mentioned he has a current family which they might know that he has another child, so he might want to talk with you first to get to know you without his family involved.
There also will be a lot of regret on his part that he has not been part of your life for so long, so I feel he will want to discuss things with you but maybe would like to meet you by himself.
What you want to do if you decide to write a letter is make sure you put your number for him to call you and gig him the best time that you are available so you do not mis his call.
If he call you then you can both set up a time to meet and talk about being in each others lives.
This way you do not have to wonder what is going to happen if you go to the door, this will leave out the unexpected.
This always give him the time to process that his son is looking for him.
People even after time has past have been able to have excellent relationship with their parents.
You have thought for a long tim about meeting him and now you feel you are ready and I am sure he will answer many questions that you have carried with you in your life.
It will help resolve many feelings that you have been feeling.
I see your point about writing a letter but at this point in my life its been 33 years and i need to close this void in me. I'm not looking for an explanation just to talk meet him and find out about him and some family history.
Then I would say you should go and meet him. When you go to his door you tell him that I am here to just talk and found out about my family history.
You asked if it was wrong to go to his door, it is not wrong. You are looking to find out more about him and about family history. I feel you are ready and you want to meet him on your terms. You feel it is best to go to his door then that is what you should do.
My only concern is if not there and say his wife answers the door what I should say?
You want to say your dad's name and that you were looking for him, you wanted to talk with him.
If she ask who you are you can tell her your name and ask what is the best time to come back.
Then when she tells you a good time you tell her that you will check bak when he is in.