Removing stripped allen bolt - SP-A outdrive

[Fishermark]

This is the 1990 Glastron project boat I am working on. It has a SP-A outdrive. I am trying to remove the lower unit. There are sever allen bolts that need to be removed. (Or at least 7 that I have found - hopefully that is all!)

It took some heat, but six loosened up. The seventh stripped. Not the threads - the top of the bolt where the allen wrench fits. I haven't decided yet what to do. Any suggestions? Because of its location, there is no good way to access it. I think what I am going to try first is to weld the allen wrench in the bolt head. That will allow me to try and turn it. If I get it loose enough I can then cut the allen wrench off and use a wrench on the stub of the allen wrench. The problem is there is not much of the bolt head to weld to.

The other option is to use a cutoff wheel and cut about where the red line is in the picture below. Cut in deep enough to remove the head of the bolt. The lower unit should then come off and I will still have a little stub that I can weld a nut to in order to remove the remainder of the bolt.

Any other ideas?

I will post the results!

 

[Fun Times]

Just an idea but maybe you can remove it like a stud by welding in a piece of all thread into the stripped out Allen head bolt hole, next use a spacer that's just wide enough to allow the bolt head to fall completely through, then run the 2 nuts up to the other end of the spacer and hope it turns out. http://www.bing.com/search?q=how%20t...9c2fe829cb986a

I wouldn't want to cut into the housing but either way, good luck.
PS, hope you don't mind you new signature line, If not, it easily removable.:usa::usa2:

 

[Fishermark]

I've welded nuts onto broken studs with success in the past. The main problem here is the design of the outdrive. Since it is between the two "flares" there is little to no room.

I've never had to do the cutting. That was recommended to me years ago by an old marine mechanic who specialized in Chrysler outboards. He said he would often have to cut through with a cut off wheel and remove a bolt or stud - then he used marine tex to fill the gap. I know believe there is any passage there that would be in danger... but yes that will be a last resort.

QUICK UPDATE: I was able to successfully weld the allen wrench in place. It seems to have a pretty secure bite. I am not going through several heat and cool cycles before I put too much pressure on it.

 

[Fishermark]

Just for documentation sake... here's a pic of the allen wrench welded into the bolt head. I am still going through several heating and cooling cycles - may not try to put too much "oomph" into turning it till tomorrow. Stay tuned!

 

[Scott Danforth]

Thats exactly how I would approach it.

 

[Dave-R]

I am not that good of a welder, so I would drill the bolt head off. Then pull the drive apart, and then I know I can get the bolt off with Kroil and heat. Dave-R

 

[Fishermark]

I am not that good of a welder, so I would drill the bolt head off.

That would be a good option if there was room for a drill, but there isn't. Not even a right angle drill. In fact, I had to cut the end off of the allen wrench to make it a little shorter.

 

[Dave-R]

Not even a little right angle die grinder, or a dremel with a stone? I have been saved by a dremel a lot of times. Let us know what happens. Dave-R