Help with broken bolts

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reivertom
Posts: 547
Joined: Tue Mar 10, 2015 6:49 pm
Location: Eastern Kentucky

Re: Help with broken bolts

Postby reivertom » Thu Jul 12, 2018 12:43 am

Believe it or not, I've used those broken bolt removers on exhaust sensors on my truck with good results. Some things they work well on and others they don't, so if you're going to drill out the flush ones anyway, it might be worth a try. Mine look like elongated screws with reverse threads and they have a square head for a wrench. I'd use the heat and penetrant also.

FrankR
Posts: 3577
Joined: Tue Mar 10, 2015 6:32 pm
Location: Florida

Re: Help with broken bolts

Postby FrankR » Thu Jul 12, 2018 3:45 am

Just a couple of words, learned thru the years and umpteen thousands of screws drilled out.

Drilling out screws is a skill and an art. Usually comes as a result of many disasters while learning. And I'm still learning.

Never run a tap into a hole that still has the remains of screw threads in it.

There is no such thing as an Easy-Out. It isn't easy, and they won't get it out. If the bolt wasn't strong enough to turn itself out, the fragile Easy-Out won't be either. But they do have their place in bolts that are broken from other causes, i.e. if twisted off while tightening.

Heli-coils are a great invention and a life saver.

If you break off a tap or Easy-Out in the hole, you are in deep doo.

BillW
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Joined: Sat Apr 11, 2015 6:35 pm
Location: Cape Cod MA

Re: Help with broken bolts

Postby BillW » Thu Jul 12, 2018 5:55 am

Frank has summarized a life time of experience into a few words. Read and read, again. There is great wisdom there.

I might add a few things from my own personal perspective. If you are going to have to drill out a bolt or screw, from an aluminum housing, you might as well PLAN on using a heli-coil. About nine times out of ten, you're going to need it, no matter how careful you are.

It is truly a great day when you are able to drill a starter hole directly down the middle of the bolt. However, this usually ends up in just being good form and really doesn't help the matter, as opposed to going a little off-center. You're going to have to split the remaining chunks of bolt out either way. What I have been having good luck with is using an 1/8" carbide burr in an electric drill, to remove material in a sideways direction, after removing as much as possible with a drill bit or two. Whether you are dead center or off center, this will allow removal of bolt material right up to the edge of the threads, which will make it easier to split out the pieces.
Last edited by BillW on Thu Jul 12, 2018 4:30 pm, edited 1 time in total.

FrankR
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Location: Florida

Re: Help with broken bolts

Postby FrankR » Thu Jul 12, 2018 7:30 am

And I agree with what Bill just said. Couldn't have said it better myself.

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20mercman
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Location: Kenosha Wisconsin

Re: Help with broken bolts

Postby 20mercman » Thu Jul 12, 2018 10:13 am

I will also have to add my "Eye" to this experience with drilling out bolts as this has been my experience as well. I have had some good luck with being able to drill out a broken bolt, but having a Mill or a very high quality drill press will improve your chances. Be very careful to not break off a tap in the hole. Sometimes you can get the tap to catch the remains of the thread of the bolt and they you can work it out with a sharp probe. Careful work, and not always the result you want. This is why I went to the welding method I was talking about in my other posts. By building up weld onto the broken bolt or stud, you are not only heating the bolt, you are giving you something to grab with a vice grip. Even if it breaks off a second time, do it again. A welder is really one of your best friends in restoring these old motors. Learning to TIG weld was a real asset in getting the results I needed.

In the most recent restoration I have just completed, ( A 1972 Mercury 4hp.), it was not broken bolts that was the issue, it was broken aluminum. These motors had a really nice shallow water drive option. The issue, as it had been a rental motor, both of the aluminum bosses in the swivel bracket had been broken off. Also, the skeg had the usual damage and missing section. Being able to return these items to as new or better condition could not be done without welding. If you can weld, great, otherwise make friends with one! A case of beer can go a long way in saying thanks for your help!

Steve

PugetSoundBoater
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Joined: Fri Oct 16, 2015 2:30 pm
Location: western Washington

Re: Help with broken bolts

Postby PugetSoundBoater » Thu Jul 12, 2018 10:59 am

I have used a brand new left hand drill bit with success,nice and sharp to get a bight, after the penetrant and heat has been patiently applied. If the bolt protrudes ,i also hit the end of the bolt after the heat and penetrant. Also wire brush all around the bolt where it enters the surface to let the penetrant soak in.
"We only learn in two ways,one from reading,the other by association with smarter people" Will Rogers

bobw
Posts: 148
Joined: Sun Jan 22, 2017 8:21 pm

Re: Help with broken bolts

Postby bobw » Thu Jul 12, 2018 11:20 am

Just to echo 20mercman, access to a welder can be a real value. On my '72 Evinrude restoration I had 3 powerhead bolts where the bolt heads were totally eaten away with salt water corrosion. I just broke off what was left of those heads and pulled the power head off. Then took it to a welder friend of mine who built up the broken bolt stubs and then welded a nut onto the built-up stub. The heat from the welding process broke the corrosion loose and we were able to back the bolts right out. Also did the same thing with a broken motor mount screw on another motor. I've been successful with the torch and fluid approach on many bolts but when they are broken off flush with the mating surface the weld process is sure helpful.
Bob
AOMCI Member

1954 Johnson CD-11
1958 Johnson QD-19
1972 Evinrude 25202

outbdnut2
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Joined: Wed Apr 27, 2016 2:46 pm

Re: Help with broken bolts

Postby outbdnut2 » Thu Jul 12, 2018 11:38 am

A lot of good info here that is spot-on! I find easy-outs and similar tools work about 20% of the time, but are worth a try. If you are lucky, what's left of the bolt will break free as you drill more and more of it out. I start with a small drill bit and keep increasing the bit size.
Dave

bobw
Posts: 148
Joined: Sun Jan 22, 2017 8:21 pm

Re: Help with broken bolts

Postby bobw » Thu Jul 12, 2018 12:07 pm

So on the related topic, what are everyone's thoughts on good penetrating fluids to use for frozen, corroded or broken bolts? Guess I've used PB Blaster the most but also had good luck using beeswax after heating a bolt.
Bob
AOMCI Member

1954 Johnson CD-11
1958 Johnson QD-19
1972 Evinrude 25202

NJ-boatbuilder57
Posts: 199
Joined: Fri Aug 25, 2017 10:59 am
Location: New Jersey

Re: Help with broken bolts

Postby NJ-boatbuilder57 » Thu Jul 12, 2018 1:26 pm

PB is pretty decent stuff, but the best is a 50/50 mix of acetone & automatic transmission fluid. When I first heard of that homebrew, I was skeptical, but now I'm a believer!

Can't explain the chemistry of it; I really don't know how-why it works......but it gets the job done more often than not.


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