Broken Bolt V-4 90hp

[bonitasprings]

On the flywheel a hardened bolt for the harmonic balancer had broken off flush prior to my purchase of this boat. When I attempted to extract it the extractor broke off flush! No drill bit I have will even scratch it.

Please advise

 

[kenmyfam]

Re: Broken Bolt V-4 90hp

Can you get the flywheel off ?? or is that why it broke in the first place ?? Do not make things worse by forcing the other threads and damaging them though.
Need to know this situation first.

 

[HybridMX6]

Re: Broken Bolt V-4 90hp

Hmm, don't know how well this would work for grade 8 hardened bolt that broke, but I had a few bolts break on me when I rebuilt a 60hp and I used a Dremel to cut a slot in the broken bolt, and then used an impact driver to get it out. Worked on all the bolts I had to remove. Parts were removed from the motor though before attempting. Gonna be hard if the flywheel is still on the engine.

 

[rodbolt]

Re: Broken Bolt V-4 90hp

run the boat to a welding shop,have them weld a nut on the extractor and remove it.
then the correct procedure is to drill and retap the bolt hole.
NEVER EVER use esyouts or any other extractor that swells the bolt when extracting.
espesially on bolts three eighths of an inch or less.
it simply swells the metal into an already stuck thread.

 

[bonitasprings]

Re: Broken Bolt V-4 90hp

Situation: (my goal is to pull the flywheel)

In one of the 3 threaded holes used for the harmonic balancer puller a previous owner had broken off a grade 8 bolt flush with the surface of the flywheel. Took a cobalt bit to drill it out for the extractor. When the extractor was inserted and turned in attempt to remove the broken grade 8 IT broke off flush with the top of the broken grade 8. I tried to drill the broken extractor but couldn't even scratch it. I would imagine it is harder than the grade 8. My question is what kind of bit will drill that out so I can attempt another extraction? (with heat this time)

 

[bonitasprings]

Re: Broken Bolt V-4 90hp

Thanks Rodbolt. That makes sense.

 

[rodbolt]

Re: Broken Bolt V-4 90hp

nothing will drill that tool steel extractor.
either use an EDM machine(tap burner) or have a nut welded to it and turn it the opposite direction you did to break it.
then use the correct sized tap drill and drill and retap the hole.
you can try the dremel a slot in the extractor,especially if its a spriral tapered type.
never seen it work but you can try.
just dont tear up the hole in the flywheel.

 

[bktheking]

Re: Broken Bolt V-4 90hp

Try this, I have removed MANY and I mean almost all the flywheel's i've pulled using this method- snowblowers, outboards, small engines. I've used my puller once and this way every other time. Vibration removes a flywheel as an alternative to force, I don't like removing with a puller because of this reason, bolts break and leave you in a predicament. Air chisel and prybar.


Spray penetrating oil down around where the crank comes up through the flywheel. Remove the crank nut and thread it back on until the top of the nut is even with the crank snout. Take a prybar and place it between the flywheel and the powerhead, place carefully as not to damage anything. While pushing downward on the bar to provide upward leverage place the air chisel in the indent at the top of the crank and hammer away, it may take a few tries with a stubborn flywheel but the all eventually come off, at least they have for me.


Or you could mess around drilling and tapping and and and.......

PS - use the bottom type fitting in the chisel, the rounded point one.

 

[rodbolt]

Re: Broken Bolt V-4 90hp

that is a good method, for breaking the bottom roller bearing on that V4.
why not simply do as per the service manual?
had the poster drilled and retapped instead of trying to drill and extract this thread would not be here.
now we have to correct the second mistake and try not to make a third mistake.
bolt breakage is 99% operator error.
usually due to incorrect puller setup or trying to use grade 8 bolts and tin washers.
once under pressure the puller must remain parralell with the flywheel,especially when using grade 8 bolts,or the bolts snap.
its also why I use grade 5. not quite so brittle.
always remember,most modern two strokes use a caged ball bearing on the lower crank journal to control axial(up and down) thrust loads.
try not to hammer on it.

 

[bonitasprings]

Re: Broken Bolt V-4 90hp

Correction:

I had been referring to the original broken bolt as "grade 8". That was an assumption. It was broken off prior to my ownership....There, now I have once again made an *** of myself! (after first doing so trying to extract the broken bolt!)

 

[bktheking]

Re: Broken Bolt V-4 90hp

Bonita, take my suggestion or leave it, rodbolt seems to think you`d take out a bearing, I say otherwise, we can just agree to disagree. Never taken bearings out , this method was taught to me by my father, a mechanic since 61, I trust his methods. If it were going to do damage it`s a method he wouldn`t use and if for some reason it taken out a bearing cause it`s weak I`d rather have it happen in my garage then out on the lake with a running motor. If you can`t get that bolt out it may be the only method to use, in which case the reward outweighs the risk

 

[kenmyfam]

Re: Broken Bolt V-4 90hp

Or lay it out properly and drill and tap 3 fresh holes in it. Must make certain that there is enough "meat" where you do this. Same diameter pattern and 60 degrees from the originals has done the trick for me before. However you MUST make certain that will work in your application. Machine shop can do this if you are not confident to do it.
Just my 2 cents though.

 

[McGR]

Re: Broken Bolt V-4 90hp

You could try grinding it out with a small abrasive Dremel bit like the one shown below. If you do this, you will probably go through several bits before the job is done, so get more than one.

You could also try giving it some hard blows with a punch. Extractor metal is somewhat brittle and sometimes you can get lucky and shatter them with some hard hits.

 

[bonitasprings]

Re: Broken Bolt V-4 90hp

Some really great ideas from you guys! 3 new holes. weld to the extrator, punch it out, vibration.

This is the kind of stuff that makes this such a great site and I am proud to be a part of it!

Letcha know how it turns out!

Thanks to all !

Bonita Springs, Florida

 

[jonesg]

Re: Broken Bolt V-4 90hp

I did the exact same thing on a motorbike block yrs ago, ezouts don't get anywhere near my engines now. They're brittle as glass.!
They cannot be drilled, they can only really be ground.

Unless the broken bolt is corroded in place you might be able to drive it with a prick punch and unscrew it out, just tap it lightly around its edge and see if it turns.

If not then I'd try a puddle weld in the middle of a nut placed over the broken bolt. Or have the local machine shop put the EDM on it and spark it away.

 

[billy4hp]

Re: Broken Bolt V-4 90hp

Bonita, take my suggestion or leave it, rodbolt seems to think you`d take out a bearing, I say otherwise, we can just agree to disagree. Never taken bearings out , this method was taught to me by my father, a mechanic since 61, I trust his methods. If it were going to do damage it`s a method he wouldn`t use and if for some reason it taken out a bearing cause it`s weak I`d rather have it happen in my garage then out on the lake with a running motor. If you can`t get that bolt out it may be the only method to use, in which case the reward outweighs the risk

X2 I agree to disagree

Ball joint, air hammer yes

Tie rod end, air hammer yes

Idler arm, air hammer yes

Crankshaft, air hammer no friggin way....

If they wanted you to remove the flywheel by means of vibration they would not have tapped the flywheel for a puller.

JMHO

 

[bktheking]

Re: Broken Bolt V-4 90hp

If they wanted you to remove the flywheel by means of vibration they would not have tapped the flywheel for a puller.

JMHO

Agreed and next time the puller doesn't work for the rest of the people out there (in this case he can't even use one!), don't take the recommendation of hitting the puller top with a sledge which countless people have done to safely remove their flywheels, google outboard flywheel removal and see just how many get them off with hammer force, I think you will be surprised.

 

[blimp]

Re: Broken Bolt V-4 90hp

Agreed and next time the puller doesn't work for the rest of the people out there (in this case he can't even use one!), don't take the recommendation of hitting the puller top with a sledge which countless people have done to safely remove their flywheels, google outboard flywheel removal and see just how many get them off with hammer force, I think you will be surprised.

HAH! I just did that on my flywheel. Using impact wrench on puller for an hour wouldn't pull it off. Gave the puller a good smack with the hammer, POP, came right off.

 

[bktheking]

Re: Broken Bolt V-4 90hp

HAH! I just did that on my flywheel. Using impact wrench on puller for an hour wouldn't pull it off. Gave the puller a good smack with the hammer, POP, came right off.

Like I say to my wife, It's not just a hat rack

 

[billy4hp]

Re: Broken Bolt V-4 90hp

Agreed and next time the puller doesn't work for the rest of the people out there (in this case he can't even use one!), don't take the recommendation of hitting the puller top with a sledge which countless people have done to safely remove their flywheels, google outboard flywheel removal and see just how many get them off with hammer force, I think you will be surprised.

Not to get off track, next time, smack the end of the puller with a dead blow hammer once you get it under reasonable tension... Works like a charm, you'd be surprised and you don't risk the of ruining the thrust bearing with repeated blows or distorting the end of the crankshaft or worse if your air hammer slips and you miss the target ...

Using puller's is my normal 9 - 5 for the last 20 odd years or so...

JMHO, to each his own...

So Bonita, how you coming along?