Lower Unit issue - 1959 Seahorse 18

I am the new owner of a 59 Seahorse 18. In trying to do the right thing before starting it for the first time in 8 years, I replaced the impeller. There are 5 bolts holding on the lower unit - 4 little ones underneath, and 1 big one on top in the back. It appears to be 3/8" Stainless steel. It was in REALLY tight, and in pulling it out, I twisted it off. It is still sticking up about 1/4" when you take the lower unit out, but it is stuck good. The motor runs great, but I am afraid that this bolt takes most of the torque from the prop while underway. Any ideas on how to get this out? The fact it is SS makes me think it may be very difficult.

On a side note, the starter sticks in the engaged position. Any ideas there?

Thanks,
Steve

Re: Lower Unit issue - 1959 Seahorse 18

You are really lucky, if you have a 1/4" sticking up then drilling will not be necessary. All you need is a propane torch, a helper, a vise and a pair of vise grips. First clamp the gearcase in the vise, and adjust the vise grips to fit the stud tightly. Anytime that a torch is used, a fire extinguisher should be within reach, and ready to use. Don't burn your garage down to get a broken stud out. A pan of cold water is handy too if the stud doesn't come out the first time. Ok, have your helper heat the housing around the broken stud, moving the torch, heating the casting around the stud evenly. Keep the heat on, and without burning yourself, clamp the visegrips on the broken stud, put some counter clockwise pressure on the stud, and if it begins to move work it back, and forth and gently turn it out. If it doesn't move, keep the heat on, and cool off your visegrips in the water, when you clamp the cool visegrips on, they will draw the heat away from the stud shrinking it. Gently try to move the broken stud, if it still doesn't move, you can try penetrating oil, and let it cool completely, then repeat with the heat. If it still doesn't come, a set of good cobalt bits (stainless is tough stuff) and drilling is the only other option.

Re: Lower Unit issue - 1959 Seahorse 18

and let me add: DO NOT use EZ-out extractors to try to get it out. It's probably a 90 percent chance that they will just break off in there, and they are nearly impossible to get out...

I have a set of left handed twist cobalt drill bits for this stuff.

Re: Lower Unit issue - 1959 Seahorse 18

Try the other suggestion first, heat works wonders.

From the volvo enthuiast site, lots of machine shops use this trick.
Works even if the stud is broken flush or beneath the threaded surface.


Removing Broken Studs With an Electric Welder. [Tip from Gary DeFrancesco] Last spring I removed the head off my '87 745T due to a broken stud. In my case, the stud broke flush with the head, so there was no way to get a wrench on it. Took the head to a head shop and had the machinist replace all the studs, figuring that if one stud is bad, more were ready to let go. The machinist trick to removing the remaining studs was amazingly simple and effective. He hooked up the hot side of his welder to the stud, the ground to the block. Set the welder for about 150 amps., then turned the welder on for 2 seconds. The studs after this treatment are hot to the touch, and the head is a bit warm. But the crud in the threads that makes the stud stick is all burned out. It is the crud that is causing the high electrical resistance. Hence, it is the crud that really heats up and burns off. With the curd burned off, he is able to easily unscrew the stud. He finds better than 90% of stuck studs can be removed this way. And there is no warping of the head since the heat is pretty much contained to the cruddy threads and is only applied briefly. Just one of those welder tricks I have filed away for the day when I get a welder.

another trick is spotweld a nut to the broken bolt.
Heres a video , this one using a mig but arc works too.
http://www.ehow.com/video_2327766_removing-broken-stud-learn-how.html

Re: Lower Unit issue - 1959 Seahorse 18

jonesg said:

Removing Broken Studs With an Electric Welder. [Tip from Gary DeFrancesco] The studs after this treatment are hot to the touch, and the head is a bit warm. But the crud in the threads that makes the stud stick is all burned out. It is the crud that is causing the high electrical resistance. Hence, it is the crud that really heats up and burns off. With the curd burned off, he is able to easily unscrew the stud. He finds better than 90% of stuck studs can be removed this way. And there is no warping of the head since the heat is pretty much contained to the cruddy threads and is only applied briefly. Just one of those welder tricks I have filed away for the day when I get a welder.

Click to expand...

That's a nifty trick! I'm glad you shared it. I may never be able to use it, but then again ....... love to learn new tricks. Those welders know a lot of good stuff!

Re: Lower Unit issue - 1959 Seahorse 18

Thanks guys, for all of your help! I will keep you posted on the progress. I will try to get it done this week. Thanks again.