I tore apart the tractor today to fix a crack in the thermostat housing on the head. The previous owner left straight water in it during the winter and it cracked the head around the thermostat housing.

I repaired it with JB weld, but when it heated up, it broke the repair.

Today, I took it apart, pulled the alternator, radiator, and water pump so I could get to it good. I took a diamond tip on a dremel mototool and ground out all of the JB weld I had put in the crack, getting it prepared to weld.

When I braze it, I will pour ashes from the fireplace around it in a heap to insulate it and let it cool down slowly so it won't crack again. (or at least that is what I'm thinking right at the moment!)

I want to do a permanent repair so I don't have to keep worrying about whether it has enough water in it, and it will hold antifreeze.

My tractor is a 70's model grey market tractor, a 16 HP Mitsubishi with a 3 speed transmission, a low, medium and high range, and a 3 speed PTO. I have a rototiller for it, mower, grader blade, and a front end loader (which I haven't mounted yet.)

Sounds like a good tractor once you get the crack fixed. I would like a tractor, but I only have 3/4 of an acre, so I'll get by borrowing my neighbor's.

I got the crack fixed. I took the waterpump, alternator, and radiator off so I had good access to it. When I brazed it the first time, it cracked in the weld as it cooled.

I brazed it a second time, then as it cooled, I hammered all along the crack with the point of my chipping hammer until it was much cooler, then I zip tied my welding glove around it so it would cool slowly. It held!

I put everything back together but I still have to put antifreeze in it. Hopefully I'll do that tomorrow.

I posted the pictures below. The first is a closeup of the crack. The second is a poor example of my brazing, but it did hold! The third is me hammering all along the crack to stress relieve it. The last one is a shot of the engine before I started the repair, showing the little 2 cylinder diesel engine.