Broken Bolt Extractors?

Carl

Carl

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Staff member
Welp, I have a broken lower unit bolt on my 1985 9.9hp.
Anyone have much luck with the left-hand thread drill bit bolt extractor kits?
I'm assuming penetrating oil and a little carefully applied heat will help the process.
Might also order a set of SAE taps to clean the threads on all six bolt holes too.
 
I've never had much luck with them, but it doesn't hurt to try. I have better luck with high heat to weaken corrosion's grip, drilling out the bolt, or welding to it to get a better grip and then backing out. Heat from welding helps a lot too. How deep is the break off? Steel bolt in aluminum housing? If so, that is hard to drill out because the drill bit wants to slip to one and start cutting aluminum.

Definitley clean all threads. I keep many taps and dies on hand and use them in every restoration I do. I won't put something back together until the fasteners have been wire wheeled and threads chased if they don't turn by hand.
 
I assume its aluminum.
Not sure how deep yet, stopped trying to take the lower unit off at that point. Going to hit the all the bolts with penetrating oil and let them sit for the week.
I need to check and make sure I have a center punch to mark the center of the bolt before I start drilling.
 
I would heat the remaining bolts a bit before trying to remove them also. Proceed slowly if any of the others balk at letting go. You have been given excellent advice above. I’ve faced that situation before multiple times and it’s never easy. Good sharp drill bits and careful advancement with plenty oil usually is the order of the day. Good luck!
 
Carl said:
I assume its aluminum.
Not sure how deep yet, stopped trying to take the lower unit off at that point. Going to hit the all the bolts with penetrating oil and let them sit for the week.
I need to check and make sure I have a center punch to mark the center of the bolt before I start drilling.
Click to expand...
Carl, Aluminum housing with stainless steel bolts. Left hand drill bits will on occasion, grab the broken bolt and back it right out, just about the time you almost all the way thru the bolt. The combination of removing the center mass plus the heat generated by drilling loosens it right up.
Welding a nut to the exposed end of the broken bolt is another option.
 
Thanks everyone. I’ve got to order some tools and parts, hope to be ready this weekend. I’ll update progress.
 
From 40 years working maintenance in chemical plants and power plants. Kroil is the best penetrating oil. Spray 2 or 3 times a day before trying to take it out. We always used easy outs. Drill your hole and install your easy out. As you're trying to put pressure on removing. Have someone else take a hammer and taping the easy out at the same time. You might also take a punch and tap it a couple times as you spray your oil. If all else fails, drill it out and tap new threads only if you have enough metal left.
 
Agree on the Kroil. A few heating/cooling cycles also helpful, particularly with different metals and different expansion rates. Heating will also help defeat any threadlocker that may have been used. Icy/cold penetrant can be useful immediately post heating to cool quickly... then more Kroil.
 
Not related to the OP at all, but when I had hardware removed from my ankle after surgery to repair from a car accident, the surgeon broke off several screw heads in the healed bones and used an EZ-Out to extract them. Stainless screws (I think) in bone. No idea how that compares to steel and aluminum. :)
 
We deal with broken bolts a lot here at work and at home too. Hardware store EZ outs generally dont work great, I have a MAC " multi spline screw extractor " set that works great. If the bolt is in aluminum its definitely harder to get out! Make sure you're on center so if it bad enough you can drill to tap drill size and retap. Good luck! getting one out is pretty satisfying !
 
Carl,
If I am understanding this correctly, you broke the head off a bolt trying to remove the lower unit, at this point you stopped. I believe that even if you snap the heads off all the other bolts and remove the lower unit, you will now have access to the studs that are left stuck into the mid section. They are usually bolts with a shoulder. At this point you could try a to grab them with a pipe wrench or a stud extractor. Maybe? Just a thought.
 
Possibly. Just have to see once I get them all off, how much of the bolt, if any, is exposed.
 
Carl said:
Possibly. Just have to see once I get them all off, how much of the bolt, if any, is exposed.
Click to expand...
Carl,
Just curious, were you successful in extracting the broken bolt? The left hand drill bit idea sounded pretty promising.
RM
 
Nope. The ones I ordered online had great reviews but proved worthless. Drill bits could not make a dent in the stainless bolt. My cheap harbor freight bits worked great. Heated the bolt and put on some penetrating oil. Drilled pilot hole, inserted the left-hand bit, they would grab for a second and then spin. Not enough bite. Gradually increased the size of the pilot bit and extractor until I ran out of bolt. Re-threaded the hole with the taps I bought. Which were an excellent purchase. Also used them to clean all the other bolt hole threads.
Got a full refund today for the worthless bits and extractor.
Live and learn!
 
Carl

Glad you got the bolts out. Your experience with extractors is the same as mine. Their success rate isn't good enough for me so I look for other solutions. One tool I'd like to have in my arsenal is a heat induction bolt remover. If you haven't seen one go to youtube and search that term. They are slick.
 
In my experience stainless is extremely hard to get out and it’s very easy to gall your bolts up if you put them in with an impact dry. Be careful or you too will be extracting broken bolts!
 
Choose an antiseize formulated for stainless. Used extensively in food, hospital and marine environments.
You can thank me later.😁
Oh,,, An inch pound torque wrench comes in handy.
 
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