Fixing an oil leak

This is generic question about oil leaks in tractors.
I have a Farmall Super A that has an oil leak in what appears to be a frost plug, but is a metal plug that closes a machine hole for the cam shaft. The plug goes in the machined hole and the dome of the plug is tapped in to seal the plug.
I have replaced the plug twice. When I rebuilt the engine the original plug was not leaking. I put in a new plug and smacked it hard using a 1/2 inch extension as the piece of metal up against the dome. Well it leaked. So I split the tractor and did it again using the Aviation Gasket liquid on the plug before smacking it again.
I am now ready to split the tractor again to fix the leak that is still there. Yes I did clean the hole out good both times.
Before I do that I thought about using some type of oil seal material to seal the leak. But that seems a little dangerous in that I might seal up an oil passage on the crank or the valve train.
Has anyone ever used a commercial product to fix an oil leak and did it work?
Did grandpa have a solution that would fix this?
I am not opposed to splitting the tractor. Tractor is in the shop and the tear down has started, was just wonder what everyones experience has been on this.

Make sure the drain hole behind the camshaft is open. I don't think that engine has a cam shaft bushing in that end but if it does, it can block the drain back hole if installed too deep.

As for the plug, I would use a much larger tool to expand that plug to cover more area of the plug. If you cave middle in too far it will loosen the plug in bore.

Assuming you are talking about a plug that is convex toward the outside. Our Deere 50 started dripping through this type of plug in the bottom of the gear case. A solid rap, using the big end of a 1/2 inch extension fixed the leak.

Thank you for the wise info

You should not be installing this by driving it in with an extension. That is your problem. There is a special tool that is used for driving in freeze plugs. Your oil plug is essentially the same thing as a freeze plug. The tool has a mushroomed head on it that matches up to the inside of the freeze plug. Different sizes to match up to the various sizes of freeze plugs. This makes the outer edge of the freeze plug taper in as it is being driven into the hole. Hitting it in the middle with an extension will cause it to bend other than just at the outer edge. It'll cause the plug to bend in the middle, and pull the outer edge in at 2 points, and not evenly all the way around.

I agree with what Pete said on the install method.

Also look for the unexpected, a damaged surface where the plug seals, the cam shimmed wrong and riding back against the plug, or some strange casting problem, porosity???

As for sealer, yes, I would be inclined to try sealing it, especially if you verify the leak is a damaged sealing surface. Of the top of my head I'm thinking JB Weld. If applied sparingly it won't block any passages, then wipe some around the outside.

But will add, how are you verifying the leak is the cam plug?

Is it possible the rear main is slinging oil up there, or could be coming down from the valve cover?

With this many fails, I would be tempted to do a test run on the engine stand just to be sure.

I have always put them with the dome in, not out. Never had a problem. A little non hardening permatex or av sealer and it shouldn't leak. Dome out will always leak. I just use a socket that fits inside the rim. A couple taps to set it just inside the outer edge and done. Have only seen it dome out a couple times and they did leak. Sisters gremlin when I was 17. She was in college and came home saying she could always smell coolant but didn't lose much and never a puddle. 39 cent fix

Sounds like it's a Welch plug you're talking about. Just a dished disc, not the cup type. They go in convex side out and should be driven with a flat tool of the same diameter or close to it. And driven in till it's flat.

As Mike said you need to specify which type of plug you are working on in order to get correct advise.

We always used the cup type plugs with the convex side in. With a small amount of sealer around the outside of the plug and drive it in with a socket a little smaller than the inside of the cup. I dont recall ever using the disc type. This was on car and truck engines. Never had a problem.