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Am trying to drop the lower unit to replace the impeller and other water pump parts.
'90 Evinrude 48SPL
The 5/8" center housing bolt in front of the cavitation plate is frozen. Actually, I have moved it a littel, but it is very tough going. Am worried about pushing too hard. The other four 9/16" bolts broke free easily.
Have been soaking in spray penetrant, but not sure how well that is getting in there even with the motor tilted full up.

Anything else I should be trying?

Previous owner said he's had no problems but said its been years since the impeller was replaced. Maybe this is why. I hope not.

Jim

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Heat the bolt and use an impact wrench but don't get aggressive. I've had bolts that have required several heating before they break free.

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Glad to see another sailor here.

I'm not familiar with that motor, but I hate stuck bolt, but I hate broken ones more.

1. You've done penetrant...
2. My next step is usually a 15" breaker bar with reasonable force.
3. After that, my next step is a little heat on the area from a torch (with fire ext near) and a breaker bar.

Good luck.

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In the paint department of DIY stores (Home Depot, Lowe's) you can get a heat gun which is great for heating bolts (and the area around them). Not as much hassle as a torch but watch your fingers they do get HOT. I've had great success with mine vs that LAST bolt that refuses to budge

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Heat works great and is the best tool when all else fails. The problem with the big breaker bar is that it'll snap a bolt much easier than a momentary impulse generated from an impact wrench or even a quick blow with a hammer. If it were a grade 8 bolt, you'd be able to effectively strong arm with a breaker bar, but anything else runs the risk of snapping.

Now even if you can get the bolt just a little loose, you're more than half way home. At that point, I soak in penetrating oil and loosen until I hit too much friction. Then I tighten again and loosen just a bit more. Keep doing this along with the penetrating oil and you'll get it. Takes a while but it's not nearly as much hassle as breaking the bolt off and having to deal with that mess!

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Here's what I've done and freed the most stuborn froze up bolts. If you can get a box end wrench on the bolt, take a center punch and punch the center of the bolt head. The get a pnuematic chipping hammer with a pointed tip, adjust the air so that your not at full throttle on the chipping hammer. Put the wrench on the bolt then put the tip of the chizzle point in the spot where you center punched the bolt head, put some tork on it and start pnuematic hammering. You can adjust the air pressure up as high as you can and still keep the tip of the chizzle point in place, this should allow you to break free the bolt, good luck

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I use Blaster on frozen bolts. the main thing is patience. Soak it with blaster, let it sit overnight, then try to turn it gently or maybe pop it with an impact wrench. Once you turn it a fraction your home free. Trouble is, sometimes the head will turn a fraction and the bolt didn`t turn. That's bad news its ready to snap. 9/16" is a pretty thick bolt. I think you can do it. If you can`t move it, just have patience soak it and try tomorrow. Let us know how it turns out.

rich

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I forgot to mention that I always use a torch, along with the Blaster. Heat the surrounding area, not the bolt

Rich

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Thanks for all the replies and advice.

Don't have an impact wrench or similar tools. Did use heat and patience, avoided the breaker bar. Problem is, this is the "long" bolt with threads far removed from the head and difficult to get heat to the threaded hole area. Long story short, I broke it. Damn! I feel like an idiot. I guess I should have gone more slowly. Now I am where I am.

It's a 9/16 dia SS (obviously not grade 5)hex head bolt, broken just fractionally above the aluminum casting. Easy to get penetrant in there now. Hmm. I've talked in casually in the past with my auto gear head friends about this situation, and know there are various tools/techniques to employ here. I'd like to get that nub out with the housing threads intact and avoid helicoils and all that stuff, although it does appear to be a hefty piece of aluminum in that area.

Okay, so the lower unit is off and I've pulled the water pump and looked at the impeller and plate and grommets. Not Changing this a moment too soon. It may be the original! Am also changing the housing, going with all OEM parts. Trying to do this right.

So, any further advice here for a dejected and embarrassed soul?

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Last I broke a bolt I went to my local (trusted) auto engine rebuild shop. Towed the whole rig there. For $25 he removed what was left of the bolt and without any further damage I was good to go.
It was well worth it. They made it look easy.
Pete

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My dad was a machinist for many years, his advice, hit the bolt head with a hammer while spraying the penetrant, the vibration loosens the corrosion momentarily and allows the oil in.
As stated before, heat is the final solution. MartyD

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Jim -

Let me say, welcome to the club. There are thousands of us. It sucks when it happens but it always comes out okay in the end. The water pump housing is the 2nd most favored place to break a bolt.

If you have part of the shaft exposed, consider taking a dremel (or hacksaw) and cutting a slot. Not too wide but deep for a long shafted flat head screw driver. Soak that puppy in PB Blaster a day or two (visit and recoat 2x day.) Give it a turn. If no joy, do as Binkie says: heat it with a propane (not MAP) torch you can buy at the hardware store. Let it heat up for 10 minutes. Give it a try, if no success, reheat again. Many times the combination of heating, cooling in conjunction to the PB Blaster does the trick.

If the head is inside the threaded section, you can try an easy-out extractor. These are a reverse threaded drill bit. They work but you have to use gentle but firm pressure . Too much force will break the extractor.

If all of this is too much to bear, check you local mechanic shop. They break bolts all the time.

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You will now have to drill the bolt out. Small enough bit to drill the core out but not go into the threads. You have to use a cobalt drill bit, then an easy out. If you bread the easy out off, you are really screwed.:( For me, next stop is a machine shop. It will probably not cast more that the tools now needed. its a simple job for them.

rich

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A second to most replies on the bolt's demise, WELCOME TO A VERY NON-EXCLUSIVE CLUB! Oh, Lord how I hate the feel of the socket wrench loosing all resistance on that bolt head. However, over the years I've had some mighty triumphs (thank you heat gun, impact wrench and patience) and have grown insensitive to the now occassional failure. I now take those defeats to an engine repair shop (a good machine shop or automechanic will also do) where I find out I am among the multitude of headsnappers rather than the lone idiot. Best advice when you take it there: Watch what they do and ask questions so you can learn from the pros. If they don't want to share then take your business elsewhere.

PS - Easy outs are trickey and you can cause some REAL damage. If the head snaps admit defeat and head for Ye Olde Shoppe!

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an update, if anybody is interested in my little sicheeation...

Decided to try the easyout route, mostly due to the hassle of towing the whole rig to a local machine shop. Jury is still out as to whether that was a good decision:
Enough of the nub (7/16 SS) protruding to allow me to smooth it out with the Dremel.
Eyeballed the center and marked it with a Sharpie marker. Hit that dot with a center punch good and hard. Started with a 7/64 Cobalt bit. Worked very slowly, but got it all the way through the bolt, a little over an inch. Good news, not a blind hole. By my eye, close to down the middle. Gradually reamed that out to 1/4" with progressively larger bits. No problem, but I went very slowly with the 1/4 bit, constantly checking my center, hoping to avoid breaking through the wall. Looks good all the way through the hole. Shot PB Blaster in the hole and let it soak a bit, at last getting some help from gravity. Tried a couple of times heating the aluminum casting with the propane torch, but still no go with some gingerly attempts on the #4 easy out. Thought I might get lucky. Shot in a bunch more Blaster in the hole, hopefully creating a little pool around the threaded hole in the casting. She's going to sit for a few days, probably a week until I get to it. Am wondering if chucking an oversized bit and running it in reverse with the hammer drill will create enough vibration to help break the surface tension, more than just a hammer blow. Didn't want to risk breaking/dulling the bit by using the hammer drill while drilling the hole. More torch time is in my future.

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Hi,Try this, heat up the bolt and surrounding area,lay a candle or para fine wax on the bolt and let the heat draw the wax up the bolt.Then try and remove bolt .My friend told me about this and I have seen it work for myself.Try it you have nothing to lose at this point.Hope this helps ,Dino

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I would keep going with a bigger drill bit. almost down th the tread width. then you can use a bigger easyout. This worked for me. I kept drilling the hole bigger and bigger, and then the thought occurred to me that I might just be able to re-tap the hole. I used a bit that was almost the size of the bolt,without the treads, just a hair smaller. Then just screwed a tap coated with cutting oil into the hole, and presto, no more broken bolt.:D
rich

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The two week saga ends on a happy note. Whew!

Made some shop inquiries regarding extraction and found some possibilities, but the logistics were going to be painful, so I went down the road Binkie suggested in his last post.
Drilled it out to a thin walled cylinder. Kept trying heat and bigger Easyout but it just wasn't going to budge. Eventually the Easyout ate through the wall on one side. Ooops. Needed to recenter the hole. Used a 1/8" tungsten carbide cutter bit with the Dremel to get down to threads all the way around. No penetrating oil had gotten to the threads anywhere, it was "galled in place". The Dremel bit cut through stainless like butter. White alum oxide dust flew whenever I got to aluminum threads. Got it all out but the threads were a little damaged where I had gotten off center on the drill, so I decided to go with a helicoil. Drilled and tapped that without a hitch, wound in the helicoil which fit nice and snug, used anti-seize on re-assembly, and successfully got the whole motor buttoned up this weekend. Was able to hand tighten the full 1" of threads before using the torque wrench to tighten it up to spec., so I guess I managed to keep the drill true. I have nothing to base this on, but I actually have more confidence in that 18-8 stainless helicoil than I do in the original bare aluminum threads.

My keys to success? Good advice (thanks all), patience, cobalt drill bits, tungsten carbide Dremel bit, the EXACT correct size drill bit for the helicoil (in my case 29/64 for a 7/16-14 thread bolt), and of course a bit of luck, eventually.

If anyone is interested, I used these online sources when I struck out on all my local sources - reasonable prices and shipping, fast service:
helicoil kit - toolsqwik.com
bolt - boltdepot.com
First time I had tried either source. Kinda hoping I don't need to go back to them anytime soon though.

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Great info.. Great job

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Broken bolts, You conquered one of the biggest obstacles encountered when working on outboards, at least old ones.;)
rich

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Great job Jim, persistence pays off! I've come close to the helicoil method but have managed to narrowly avoid it on more than one occasion. Question: does the helicoil kit come with the tap or is that purchased separately?

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Derwd,

The helicoil kit came with the tap, 5 coils (1/2" long each, I used 2), and the plastic tool for winding it in. I suppose you can buy the coils alone but all I found in my search were kits with the tap. I did actually find an off-brand generic "helicoil type" kit in my size at Pep Boys, but shied away, figuring if I was going to do this I didn't want to cut corners.

I have read that some kits come with the drill bit too but mine didn't. No small concern here, as the required drill bit size for my little situation was not too common. I got lucky and got the last one at Lowes, otherwise I would have been ordering that online too, with shipping and all that.

Jim

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Hi,Just out of curiosity did you try what I recommended with the wax before you started to drill it out.

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Sorry fin, I forgot to try it. Not doubting that the method has been successful in other situations, but I don't think it would have worked for my problem. That thing was absolutely locked in, "galled in place" as a corrosion expert at my work surmised. There was zero evidence that any penetrating oil had gotten through, despite my emptying about a half a can on it over 10 days or so.

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On the ones I've dealt with that were sticky, the amount of salt that had accumulated between the bolt threads and the housing threads made it so tight that I can't imagine much penetrating oil, wax, or anything working its way in there. Though I am going to remember the wax trick and give it a try as capillary action could prove very useful!

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I know why that bolt was in there so tight. I had the same motor, that bolt for some reason had a tendancy to come loose, once after a water pump change out I lost it, wasting the prop, check to bolt and re-torque periodically. Lost the plate, bolt and everything.
mw

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MW,
Yikes!
Thanks much for that info. Will definitely keep an eye. As you know, that's the trailing bolt, and so therefore the main load bearing fastener resisting the moment created by prop thrust.
If I find it tends to loosen, I'll go with Loctite blue on the threads. There's an inch of threads engaged, so hopefully I'd have some warning before catastrophe hits.
Jim