Farmall H engine-block drain plug

[Alan Jacobson]

I have a 1950 Farmall H on which I would like to do a complete cooling-system drain and flush. The left side of the engine block has a drain plug with a 7/16 square-drive head that is to be removed to drain remaining coolant from the block. Does any one with loads of experience on this issue have some sage advice for removing that plug? Chances are good that it hasn't been touched in 60 years.

 

[willie in mn]

Alan
Couple things to try.
Most small pipe plugs are 3/8 square. Scrape or file off as much old dirt & paint as you can. Then see if the fem end of an old socket extension will fit. Use one that you can expect to sacrifice, might have to tap it a bit. That will get things out in the clear & can use vise-grip etc to turn.
Or try a 1/2 or 9/16 12 point socket. On larger squares, 12 point socket that is 1/8 or 3/16 oversize often works.
Once you get it out, the heck with correct police, replace with hex head brass plug.
Willie

 

[rustyfarmall]

(quoted from post at 21:48:34 07/28/10) I have a 1950 Farmall H on which I would like to do a complete cooling-system drain and flush. The left side of the engine block has a drain plug with a 7/16 square-drive head that is to be removed to drain remaining coolant from the block. Does any one with loads of experience on this issue have some sage advice for removing that plug? Chances are good that it hasn't been touched in 60 years.

The only sure way without doing damage or making even more work for yourself is to heat the plug AND a small area around the plug with a oxy/acetylene torch. Spray some penetrating oil on it as it cools, and when the oil stops smoking, spray some more, and then walk away from it for about an hour. The drain plug should come out almost with just your fingers. If it is still stuck, repeat the heat process.

 

[36 Coupe]

NEVER spray penetrating oil on hot metal.You dont know what chemicals are in the stuff.A welder had to go to the hospital after welding metal he had cleaned with brake cleaner.Oil evaporates when it hits the hot metal, whats the sense in doing it.

 

[36 Coupe]

I have square nut sockets, no need to bugger up your 3/8 drive extensions.A 12 point socket will take the corners off the plug.