stripped radiator drain hole

[1stCub]

I finally purchased a 1951 Cub to restore but have found that the radiator drain plug hole in the steering housing is stripped. Can this be tapped for a new plug. Thaks for the help

[Bigdog]

It is cast but you can drill and tap it carefully.

[Bill Blansett]

1st Cub, Big Dog is sure correct on the Be careful. Many times the 3/8 pipe thread plug is tapered enough and not all of the threads used. You may be able to just "chase" the existing stripped threads deeper with the pipe tap and clean it up. No pressure here, and "so what" if the plug inserts a little deeper. Not much lost if you give it a try. Bill

[JLollis]

You mean that plug is supposed to come out? I was never able to remove mine. I had to drain the radiator by removing the lower hose.

[John *.?-!.* cub owner]

You mean that plug is supposed to come out? I was never able to remove mine. I had to drain the radiator by removing the lower hose.

The problem with that is you don't get the tank cpm;etely drained, and there is a lot of sludge left in it.

[countershaft]

taking that drain plug out, espically if it's rusted and stuck. I had the same problem and went to heating the cast metal around the hole and ended up putting a crack in it by forcing the plug.

[JLollis]

My plug is pretty mangled from my and PO attempts to remove it. I know I need to get it out, but how? The best I could do was remove the lower hose and flush with lots of water through the radiator and the upper pipe.

[Bill Blansett]

J, You may try drilling a small hole, like maybe 3/16 dia. up through the plug and let all of the water drain out. Remove the lower water casting from the right side of the engine and the short lower hose. Try to vacuum or blow out any remaining water. Mybe you can force some KROIL up through the small hole. or through a small hose to the plug area. Drive a little dowel plug in the hole and let it set a few days. Even if you can't get the plug out you can tap the small hole for 1/4 - 20 screw and put one in. Kroil can work wonders given a little time. good luck with it. Bill

[Buzzard Wing]

I am still trying to get mine out. I ended up drilling out the middle. I put Kroil on it from time to time and figure I will get to out one day, but it can wait till I start on the front of the tractor.

[Patbretagne]

Mebe someone will correct me (please do if needed!)
If it is a steel or maleable steel 3/8 plug and if the bolster is off the tractor, a hole down through it, oxy/acetelyne blowtorch heat the plug up and wut it out with the oxy carefully and the cast will not be damaged. Otherwise drill close to tapping drill size and tap the rest out with small hammer and chisel
That however is for stuck plug.
Lost threads, how about going up to the nearest bolt size above, drill and tap and put a brass boly in place to make a plug?
These two "fixes" rely on having the right gear.
When we got Baby home with the exploded radiator, the plug was missing and of course guess what was in there? A Wine Cork, but then it is a French cub.

[Dale51]

The way I do it is to take a hex nut that will fit over the square of the
plug & take a welder & reach in and weld the nut to the plug.
Burn it in well then while still hot unscrew.

[Bus Driver]

Chasing the threads as Bill suggests is the best first method to use. Don't cut much more after the tap starts cutting again. Cutting more is easy- putting back what has been removed is difficult! For plugs that cannot be removed with a wrench, I drill the center with a cordless drill and 1/4" bit. No chance of electrical shock when the coolant starts to flow. When the system is dry, drill with increasingly larger bits until only a shell of the plug remains.Then GENTLY chisel from the side against the plug shell and collapse the shell inward. I use an 8 ounce ball pein hammer and a 3/16 cold chisel along with a 1/4 cape chisel if necessary. Clean the threads with a pipe tap. Use a good thread compound on the new plug and do NOT overtighten.

[cowboy]

Dale that is the same way I did mine. The welding gives it a thermal shock and helps loosen it. and keeps mose of the heat on the plug rather than the casting.

Billy