Drilling Broken Stud / Repair

B

Bill O'Brien

Senior Member
Well I can now join the ranks of the many who have broken a stud while getting ready to install a high compresion head!

Now I need some advice. I searched for information on drilling / repairing a broken stud but did no come up with too much. I really know nothing of the procedure so any help is appreciated.

Other than a full description of the process my main questions are:

- My engine is in the car nearing the final stages of getting her ready to run. How do I drill a straight hole into the broken stud? Is there a block mounted drill press? I really do not want to remove the engine.

- Is the 'Stud Thread Repair Kit' on Snyders recommended along with the purchase of their drill bit?

http://www.snydersantiqueauto.com/1098

- How do the helicoils actually work? I have seen mention of 'time serts' also. Any advantages or disadvantges over helicoils?

- What are the thoughts on a 'Repair Stud' with oversized threads on the bottom?

http://www.snydersantiqueauto.com/4441
 
Bill, Bratton's sells a kit that will do exactly what you want. It is called a "BROKEN HEAD STUD DRILL OUT TOOL" and the part # is 8235. I have used it a number of times with great success. It bolts into two stud holes and has a drill bushing over the broken stud forming a triangle that locks the bushing in place. The kit comes with all the tooling that you will need. I designed this kit and Bratton's realized the value and decided to market it for me. If you have further questions, send me an e-mail. Don/WI
 
I have used the method of stud removal shown on Vince Falters web site, and found it to work great !
Word of caution......make sure your ground is attached to the work as close as possible. Tape and plug all fuel sources. Cover and tape off all valve ports and cylinder bores. Keep fire extinguisher close at hand ! Other than that....doing it with the engine in the vehicle should be fine !
 
I've also used the method shown on Vince's site. It has worked great. Sometimes the washer and nut may break off on the first attemp, but it gets it out when a second washer and nut is welded in place. The heat/cooling cycles help to break loose the rust bond.
 
Bill O'Brien said:
Alas, as I am not a welder I will have to drill the stud out....
Click to expand...

I've done a number that way also. Center punch EXACTLY in the center of the broken stud. Then very carefully drill straight down with a 1/8" bit. Drill slowly and carefully so you don't break the bit in the hole. Once you reach the end of the broken stud you will feel the drill bit drop through. STOP and don't drill through the head into the cooling chamber.

Kepp increasing the bit size until you can just start to see the edge of the thread. At this point I use a dental pick and start picking away at the remaining threads of the broken stud. If I can't pick more than a few threads down, then I use a tap. When I screw it in it will often grab the threads and turn them so they can be removed.

I've never had to use a heli-coil or oversized stud.
 
Well Don/WI I read read your post and realized that you are the one who designed the drill guide sold by Brattons!! well... I just have to buy that one then!

I have placed my order. I will let you know if I have any questions! Thanks!!
 
while sorting a previous M/A Mechanics botch ups I toque d the head down I felt a stud pull ,This resulted in me having to pull the head again .They had screwed a stud on top of a broken one about 8 threads .I centre popped it Then wired one end of a piece of 3ft . 2x4 to one of the studs about a 3rd way up I placed the drill under it so the 4" side of the board would contact the back of the drill .I then used my hand to pull down on the other end as a leaver to force down on the back of the drill .I used a short 3/16 drill to start and lubed the drill bit several times with oil ,(don't use wd 40 ).and had to take the drill & bit a few times to the grinder to sharpen it . This can be done with the hood on it, made for easy work and saved straddling the Motor,
 
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