Head bolt snapped

32forddump

Senior Member
I was torquing down my head bolts when one of the bolts snapped. It was up front near the water outlet. Can I drill outand ezout bolt without removing the head?
 
Best to remove the head and attempt the retrieval with good working space and angle of attack.

Some times you are lucky and some of the bolt shank is standing proud of the block and you can remove with vise grips, or not. Depends. So if you have to drill out, having the head removable is best. Using the head seated on the block too if you don't have a drill guide keeps from wandering off with the twist drill.

Use care when snugging down cyl head bolts, normally 40--45 lbs torque is all that is needed to secure a leak free head with good surfaces of the block and head and new gasket using gasket sealer.
 

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If the bolt broke on its own accord, I would center drill it while the head is still on. The bolts are 7/16" and a little sloppy in the hole. Try a 29/64" drill bit and Make a 1/8" deep center in the stub. It may want to run back down to the bottom. If it doesnt run down, pull the head and see whats what. If its proud, you can get some vise grips on it, and if its below, you now have a center for drilling.
If its really seized, you may need to drill all the way through. Steel looks different than cast iron so dont go through the water jacket! I'd drill with a 1/4" drill and get a stubby easy out. Tap that into the hole and try to remove the stub. The stubby easy outs are way better than the spiral type, that tend to break. Now youve got a problem on yer hands! If its locked up tite. go back and forth with some PB Blaster. It should back out. Some heat may help also. If youre an advanced mechanic, you can use a left handed drill bit and/or a LH tap. That will run the screw out once the drill/tap bites.
Dont worry tho... itll back right out. Clean all the holes with a bottom tap and blow clean. Wire wheel all the bolts and use a bit of never seize on the threads. 45 lbs on a lug nut wrench is pretty substantial. You dont need a 2 foot long breaker bar for sure! ws

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I was thinking of putting a sleeve in the hole and run the 1/8 drill down through that so to drill the exact center of the stud. Once I get the center drilled I can drill a larger hole and then use a ez out.
 
I wasnt sure if you have access to a lathe or not. Youd also need a jobber length 1/8 drill bit which is pretty fragile. Id stick with a 1/4.

Take a step back for a second... Run a pencil or dowl rod into the hole and touch the bolt; mark the rod with your thumbnail or a sharp pencil, and compare it to the outside of the head for depth, Thatll tell you whether or not the bolt is above or below the deck.
The thing with the 1/8 drill is that the bolt is probably broken off uneven, and youll pay hell trying to start the drill without breaking it. That, and the bolts were probably some of Henrys' chrome vanadium steel and a bit tuffer to drill. YMMV.
A 1/4" drill has a bit more meat on its side. If you can make an accurate center, remove the head and make a drill guide from a piece of plate bolted to the deck. That way you can at least see what youre doing. Make the guide on a drill press for accuracy.
As far as soaking in P oil, hang a small can with a string as a wick to drip on the stub overnite. If the bolt is on the outside perimeter, Id warm up the block with a propane torch, again, with oil dripping on it.
Id also consider replacing all the bolts due to stretching over the years. If its by the water neck, a slite gasket leak over the years can soak the threads with cruddy water where the anti seize will help to protect it. I know this all sounds long winded for a lousy broken bolt, but as we all know, it can be simple or need to have a broken drill laser burned out. KISS if at all possible! I really hate when a simple 10 minute job turns into a 2 day oddysey!
At the power plant we used an "Extractalloy" welding rod. Especially on cast iron, the rod would touch the broken bolt, and flame out. The heat would shock the bolt and she'd screw right out. This was on some big stuff too. If theres a will theres a way! ws
 
This is what I did. I used the spring from one of the hood catches, it was the exact diameter of the hole. Then I cut a piece of copper tubing which fit inside of the spring. I drilled out the copper tubing so the drill bit fit smoothly throughg center. I drilled down into the stud about 1/4 inch deep. I vacuumed out the hole then pushed a magnetic phillups screwdriver and removed all filings. I then put a long screwdriver into the drilled hole and turned out stud. I consider myself very lucky. Beginners luck I guess. Glad thats over.Thanks for all your suggestions.By the way, I borrowed a set of model t repair manuels and it mentioned to tighten head bolts at 55#'s. I would stick with 50 at the most, or whatever feels appropriate.
 
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If you have a mig welder take the head off and weld a nut to the bolt. Heat loosens it up and then you have something to grab onto to get it out.
 
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