The Ford Barn

Ed · 06-04-2018, 10:32 PM

My Model A also has a crack in this area. It is not as large as yours, but it is in the exact same place. In most cases this is caused by freezing. In my experiences, it is not uncommon to find cracks in this area. Another area that is well known for cracking is directly under the water pump.

I would not consider brazing or welding to be an option for making a repair with a crack like this. I say this because the cast iron in this area is usually quite thin. Applying heat to thin cast iron may result in larger problems than you have now.

I have used JB Weld to repair the crack in my Model A block. I used a small Dremel tool to clean the area around the crack. I drilled several very small holes on both sides of the crack. These holes were used to press the JB Weld into, so the epoxy would have something to anchor to. I also drilled a small hole at each end of the crack to prevent spreading.

Before applying the JB Weld I cleaned the area with acetone. I used the “slow” curing JB Weld rather than the quick setting type. I applied two thin coats. After the epoxy partially set up to a tacky stage I pressed a piece of 80 grit sandpaper into the tacky epoxy to give it the look and texture of cast iron. After the epoxy completely dried, I applied a coat of paint to the area using a small brush.

This repair has lasted several years without a failure. I hope your luck is as good as mine.

06-04-2018, 10:32 PM	#20
Ed Member Join Date: May 2010 Posts: 88	Re: Cracked Block Options My Model A also has a crack in this area. It is not as large as yours, but it is in the exact same place. In most cases this is caused by freezing. In my experiences, it is not uncommon to find cracks in this area. Another area that is well known for cracking is directly under the water pump. I would not consider brazing or welding to be an option for making a repair with a crack like this. I say this because the cast iron in this area is usually quite thin. Applying heat to thin cast iron may result in larger problems than you have now. I have used JB Weld to repair the crack in my Model A block. I used a small Dremel tool to clean the area around the crack. I drilled several very small holes on both sides of the crack. These holes were used to press the JB Weld into, so the epoxy would have something to anchor to. I also drilled a small hole at each end of the crack to prevent spreading. Before applying the JB Weld I cleaned the area with acetone. I used the “slow” curing JB Weld rather than the quick setting type. I applied two thin coats. After the epoxy partially set up to a tacky stage I pressed a piece of 80 grit sandpaper into the tacky epoxy to give it the look and texture of cast iron. After the epoxy completely dried, I applied a coat of paint to the area using a small brush. This repair has lasted several years without a failure. I hope your luck is as good as mine. Last edited by Ed; 06-11-2018 at 07:06 AM.