Technical 8BA Broken Head Bolt…

This is the ******* bolt that’s a pleasure to get to because of the oil filter… I had to cut the oil filter bracket and will reweld it…

Any ideas on the best approach before I drill it out?

 

There looks like enough bolt there to weld a nut to it. I like cutting the nuts in half to make sure I get good penetration into the stud. The heat will help loosen its grip. Breaker bar or air impact should back it out.

 

Yeah. Clean the top face of the broken bolt. weld a blob of weld to it. Keep welding to it. Then weld a nut to it. But don't weld down through the nut. Weld one of the corners to the blob and weld as much as you can around between the nut and the blob. Then put a punch through the hole in the nut and try and move it. Hit it with a hammer. try and move it. Do it very gently so you don't twist it off. This has worked for me lately and works better than welding down through a nut. You could drop a washer over first to protect the deck surface. I show the method in this video. It's not a head bolt but you get the idea. I did heat around it but I wouldn't in your situation. Give it a go it might just work.
Mart.
It starts just after the 5 min mark.

 

Good advice from above posters

Drilling and retreading with a tap or hellicoil should be your last resort as it's likely you will have trouble getting that thread to seal later.

 

Those like that don't hardly scare me anymore. Welding the nut on there has always worked for me.

 

I've welded dozens with just a nut and also I've welded a flat washer to the bolt and then welded the nut to the flat washer

 

I have read that you never want to re tap the threads in a flathead block. Ford used a little different thread in the block and if you chase it with a normal tap it will leak. Someone here with more flathead experience hopefully will chime in, and correct me if I'm am wrong.

 

everyone says weld,
but does it matter whether you use tig, mig or arc (traditional) ?
I would be curious to see which method you have all used.
I would think that arc would send the most heat into the block, and ‘help’ move things along quicker.

 

I was told the same, don’t re-tap them.
Also heard to use a chaser tap /thread chaser - to clean them out
and others
said use an original head bolt with grooves cut into it, to act as a cleaner tap.

I didn’t know the thread was different, so maybe that is where the grooved original bolt idea comes from.
.

 

My dad who worked on hundreds of flatheads in his younger years taught me to make a chaser tap with a head bolt. That’s what I will do when I get this out. I smacked it with a hammer and put on more penetrant. I will leave it soak until Sunday and then weld a nut on with a wire feeder. I like the idea of using a washer and I will put some sheet metal over the deck to protect it from spatter.