Help with transom bolts/studs....

[tmaranda]

Hello forum....long time listener, first time caller.

I am in the process of replacing the Y-pipe on my boat (Mercruiser 350 with Alpha 1). Since the motor is out, I've been doing a lot of cleaning and trying to get rid of some 20+ years of rust and corrosion in some spots. The two nuts attached to the bottom bolts/studs that connect the inner transom to the outer transom were really, really bad. When I tried to pull them off, the studs sheared right off flush with the face of the inner transom. I've circled the fatally injured studs in red on this image:

Looking through various parts diagrams, it looks as though I should be able to pull or knock the studs through the transom, inside to out. Is that correct?

Second, how do I do that? I've hit them a bit with a drift from the inside of the boat, but they ain't budgin'.

Thanks in advance....

 

[Fun Times]

Hi there, what year is the boat?

Item number 17 in the following links/photo should be the design bolts you're trying to remove as they are Aluminum Bolts with possible Anodes caps for the bottom of all alpha one and early gen 2 transom assemblies for early BRAVO as well 97-8M0030655 http://www.mercruiserparts.com/bam/subassembly/30870/2203/40

You may have to heat the left over bolt area to help loosen/remove any corrosion build-up before carefully driving the bolt outwards from the inside of the boat.....PB blaster penetrating catalyst oil may get it too though...http://www.iboats.com/Pb-B-laster-P...015895223--session_id.113679097--view_id.4424
Let us know how it goes, good luck.

 

[tmaranda]

Hi there, what year is the boat?

Item number 17 in the following links/photo should be the design bolts you're trying to remove as they are Aluminum Bolts with possible Anodes caps for the bottom of all alpha one and early gen 2 transom assemblies for early BRAVO as well 97-8M0030655 http://www.mercruiserparts.com/bam/subassembly/30870/2203/40

You may have to heat the left over bolt area to help loosen/remove any corrosion build-up before carefully driving the bolt outwards from the inside of the boat.....PB blaster penetrating catalyst oil may get it too though...http://www.iboats.com/Pb-B-laster-P...015895223--**********.113679097--view_id.4424
Let us know how it goes, good luck.

It's a 1991, which makes it a Gen 2 Alpha, I believe. That part you showed is exactly what I need, I'll be ordering one today.

Thanks for the info...time to fire up the torch!

 

[Fishermark]

..time to fire up the torch!

I would be very careful with a torch in that area. A judicious use of a punch, some penetrating oil and a big hammer should be sufficient.

 

[Bondo]

Ayuh,.... Those bolts are aluminum, shouldn't need a torch,....

 

[Grub54891]

While you have them out, Check the transom for any rot, if the corroded that badly they may have been letting water migrate to the wood. My old 1985, the bolts came out perfectly, even though the transom was rotted.

 

[tmaranda]

Ayuh,.... Those bolts are aluminum, shouldn't need a torch,....

I agree that they shouldn't....and despite torching, punching, and oiling, they wouldn't budge. So, my only option was to remove the inner transom ring and the gimbal mount. The lower two bolts had corroded into three separate pieces; one piece that I first sheared off, a second piece stuck inside the transom, and the third piece stuck to the gimbal mount. Using my best detective skills, it looks link the gimbal housing o-ring failed, with allowed water into the lower bolts. The transom wood shows some rot....excellent.

So now, I get to learn about transom repair!

This is turning into a much larger project than just swapping out a y-pipe (ugh!), but I'm finding and repairing damage that absolutely needed repairing. I guess better to do it now than after something catastrophic.

I want to say thanks to all that responded to this thread, and others. It's been a great source of knowledge. Also, a big shout out to Mike at Nielsen Beaumont Marine for helping me track down parts and providing some expertise.

 

[Fishermark]

... Using my best detective skills, it looks link the gimbal housing o-ring failed, with allowed water into the lower bolts. The transom wood shows some rot....excellent.

So now, I get to learn about transom repair!

Sorry to hear the bad news. I wish I could say it was not common, but it is. And just to add to your detective skills, , you probably have the events out of order. I doubt the o ring failed which caused water to get in which caused the rot. The order is usually:

-water gets in. (Many possible ways)
-that causes rot.
-that causes the transom to get soft
-that causes more water to get in (due to flexing of the transom) and corrodes the lower bolts.

Be sure to look in the restoration forum section for a lot of good tips to rebuilding the transom. Good luck!

 

[JASinIL2006]

So now, I get to learn about transom repair!

That stinks. There are many worse ways to find out you have a problem, though. If you already have the engine and transom assembly pulled, you at least can really assess the extent of the rot. I hope it's not too extensive.

 

[tom_sd]

That stinks. There are many worse ways to find out you have a problem, though. If you already have the engine and transom assembly pulled, you at least can really assess the extent of the rot. I hope it's not too extensive.

I think that was the silver lining in this process...the rot wasn't all that bad. I got some top notch guidance from some local guys and was able to repair the damage. Reassembly starts this weekend. I'll have to post some pics of the lower studs...they were corroded into three separate pieces. Yikes.