Model A & B

Ford Garage

Broken Head Stud and Bolt Removal

The following is a series of pics of a technique for removing broken steel cylinder head studs and bolts from a Model A Ford cast iron engine block (or other castings) without damaging the block or its threads.

This technique works on flush broken studs and bolts, as well as ones that have been cobbled on with drills and easy-outs. Technique works well on aluminum cylinder heads also.

If you are one of those people that can follow a recommendation and see for yourself, great! This should work for you!


Here is a beginning and an end: A flush broken stud in the block and a formerly flush broken stud which had a flat washer and hex nut TIG welded to it. It was then soaked with Aero Kroil Penetrating Oil while hot, and backed out on the low setting of an impact gun.

The theory is that the stud absorbs a lot of heat from the TIG welding while the cast iron block remains relatively cool (compared to using a gas torch). Again, it also works well on aluminum material.

The addition of the Kroil and the cooling and shrinkage of the stud breaks the bonds between the stud and the block. The impact pulse helps break the bonds also and eases out the stud. Seems to work every time!

Place a plain steel flat washer centered over the stud. The ID of the washer should be just a bit less than the stud OD.

TIG weld the washer to the stud. I prefer to start the arc on the stud and work my way outward in a spiral while adding filler. After welding, spray liberally with Kroil and try to get it under the washer.

Be careful, but do not worry too much about welding to the block. It is cast iron, not steel, and it is also considerably cooler than either the stud or the washer.

Next TIG weld a large hex nut to the washer. Then spray liberally again with Kroil and try to get it under the washer.

Now use the impact gun on its lowest setting to back the stud out.

If the washer or nut breaks off (sometimes it will), then just repeat the procedure again! It will come out!

Stud already partially drilled-out and messed up? Not a problem!

Just place the washer over it and carefully fill the upper portion of the hole first, then TIG weld out to the washer.

It helps to drop a piece of steel rod down the hole to fill up the bottom half before welding.

Here is the drilled-out stud extracted from the block using the same technique. Just practice your TIG welding so you can fill the upper portion of the hole without fear of getting into the block threads.

If you know how to control the torch you will have no difficulty with this. It is much easier than it looks!

Now throw away every one of your drill guides, your so-called easy-outs (easy-brokes), and your 'screw extractors' before someone gets hurt! Do it now! Right this minute!


More Head Stud web pages on Ford Garage:

  1. Model A & B Cylinder Head Stud Removal Tools
  2. Model A & B Snap-On Cylinder Head Nut Wrench
  3. Model A & B Cylinder Head Nut Tightening Sequence

January 2002