farmall 806 diesel freeze plug

was just chisel plowing with my 806 and it just
blew a hole in a freeze plug. It is the one on the
very back of the block. right under the front of
the fuel tank. hole looks to be the diameter of a
pencil. looks like a real bear to get to. any
ideas? never messed with a freeze plug before. are
they hard to remove and install?

If your in a hurry and can actually knock it out, I've seen expandable freeze plugs that might work until you have more time to replace it with a proper one. Any auto parts store should have them.

You'll need to get "some" access to it, probably remove the fuel tank. Using a dull chisel, just tap it in until it turns sideways , then try to grab it with channel locks or vice grips and pull it out. If it falls inside and you can't get it out, just leave it.

Be very careful though, when tapping it in, be sure whatever tool you use doesn't cut through the rim of the plug and gouge the machined surface where it seals against the block. Also the casting behind the plug may be very close to the back of the plug. If it hits something solid, stop beating on it! You'll need to pry it out instead of knocking it in. Remember, cast iron is tough, but it will break! Cylinder liners are thin, any dent will cause disastrous failure! Don't be afraid of it, just use good judgment.

Now, going back with the new plug. Clean, scrape, and sand the machined hole to prep it for the new plug.

Getting a steel or brass plug to drive back in can be extremely difficult if you can't get a straight shot at it, and rarely will this be possible.

Rubber expandable plugs are OK, just somewhat temporary. If you use rubber, be sure the hole is completely dry, free of oil and coolant.

There is a copper expandable plug that works great. It requires a light tap to get in, then tighten the acorn nut to expand it. Completely permanent, lasts longer than a steel replacement.

If you use steel, brass, or copper expandable, seal it with some #2 Permatex or equivalent.

If it is the one at the back of the block I think it is actually about 1-1/4 it will require getting the plate on the block to move way from the block a bit to get the new one in. I have got one of those rubber expandable ones in there. I think we took the washer off and that would let us get it in with out the plate block movement previously mentioned. Been there for over 20years. I guess I should look at it. Might be ready to let go.