How to remove rusted hex bolt in outdrive

buymorecoffee

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Jan 19, 2005
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I don't know the exact name of this thing, but on the outdrive of a 470 mercruiser, just above the prop is the thing that looks like an upside down shark fin that helps control the torque from the prop. Mine is loose and moves side to side. The bolt that holds it in is accessed from the top, through a small hole. The bolt seems to be rusted and or stripped. What is the best way to remove? It's a tight space to get anything into. A friend suggested soaking in WD40 and using a spike type tool to crack or break the bolt, Any suggesstions on getting this thing out so I can replace??
 

Bondo

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Apr 17, 2002
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71,310
Re: How to remove rusted hex bolt in outdrive

Probably Easier to Break, or Melt the Zinc out of the way............(Ya, the Fin Thing)<br />Then replace it with a new 1,+ a SSteel bolt..........<br /><br />They're Pretty Cheap.......<br /><br />BTW, Welcome to the forums at iboats.com......
 

Don S

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Re: How to remove rusted hex bolt in outdrive

If the drive hasn't been taken apart for a few years, you might think about replacing the impeller while you are replacing the bolt. You have to seperate the upper and lower part of the outdrive to replace the stripped anode bolt, so you might as well get the pump fixed as well. The impeller is only good for 3 or 4 years before it needs to be replaced. You should also pull the drive and check the bellows before it costs you a gimbal bearing, ujoints, or the drive because it is full of water. It is also an expendable item like the impeller. <br />Isn't boating fun when you just don't know some things????? :eek: <br /><br /> Click here for some Mercruiser HOW TO information.
 

Bt Doctur

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Aug 29, 2004
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19,453
Re: How to remove rusted hex bolt in outdrive

try tapping in a metric allen wrench or a piece of square stock, other than that drill the tab off.
 

Don S

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Re: How to remove rusted hex bolt in outdrive

Why go to all the trouble to DRILL the tab off, it's a zinc alloy and will melt with a common propane torch. just do it out in the fresh air, the fumes aren't a good thing for breathing.<br />Melting it out is quick, easy, and can't harm the housing because it melts at a MUCH HIGHER temperature.
 

Bondo

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Re: How to remove rusted hex bolt in outdrive

can't harm the housing because it melts at a MUCH HIGHER temperature.
Especially with it being Loose..........<br />There'll be Little or No Thermal Tranfer.......<br />The Zinc will Take All the Heat........
 

rodbolt

Supreme Mariner
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Sep 1, 2003
Messages
20,066
Re: How to remove rusted hex bolt in outdrive

hello why fire up the tourch? its to easy to use a small chiesel and crack it right off. however like Dons done tole ya son. ya gotta seperate the unit to remeve the stripped bolt and replace it with a new one.<br /> now will be a great time to catch up on a bit of maint as well. dont try to just drill out the hole. makes a big ugly thing and does not work well. I have seen it done but dont reccomend it.
 

buymorecoffee

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Jan 19, 2005
Messages
4
Re: How to remove rusted hex bolt in outdrive

I'll try the chiesel and or the torch approach / I just did the maint. mentioned this past summer, changed the pump, gimble bearing, etc.
 

marinemech

Petty Officer 1st Class
Joined
Aug 12, 2004
Messages
250
Re: How to remove rusted hex bolt in outdrive

if drilling presents a problem just run a hack saw blade betweem the two housings it leaves a scar on the drive but there is more then enough metal contact between the upper and lower housings so there is no problems with torque or alignment<br />I'am not a big fan of this but then again I didn't put steel into water<br />also while back there check the amount of free play in the steering if it seem excessive you may need to replace "gimbal ring kit"
 

Capt Ken

Commander
Joined
Jul 30, 2002
Messages
2,270
Re: How to remove rusted hex bolt in outdrive

The gas produced by attempting to melt the zinc is very poisonous. Just like attempting to use a torch on a galvanized trailer. Breathing the fumes can take you down quickly. Now if you do inhale the fumes and start feeling sick, milk will lessen the effects.
 
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