70 hp LU bolt trouble...

[fishfeatures]

Hi,

i went to drop the lower unit on an '88 70hp evinrude last night, and got all bolts out except for the large one beside the anode. Over here socket sets are more commonly laid out in mm, so i put a 16mm socket on the bolt and due to salt corrosion, i have to use a good bit of force to get the bolts to budge. However the 16mm slipped twice on the bolt head , so i went out and eventually found the metric equivalent 5/8 in my brothers toolbox, but this too slipped .... i've rounded the bolt head too much i think and am in a spot of bother now .....

has anyone a suggestion of how to remove it? bear in mind that it is sitting in a recessed hole...
am getting nervous now that i may have just messed up big time.

 

[racerone]

Re: 70 hp LU bolt trouble...

See if you can get a drill in there and drill the head of the bolt off.

 

[boobie]

Re: 70 hp LU bolt trouble...

Find a tad smaller metric socket and then drive it on to the bolt. Then use some heat around it.

 

[fishfeatures]

Re: 70 hp LU bolt trouble...

Find a tad smaller metric socket and then drive it on to the bolt. Then use some heat around it.

Ok , I'd rather give this a go first than try drilling it ( my drilling is suspect at times)......what's the next size down in metric boobie .

 

[boobie]

Re: 70 hp LU bolt trouble...

Maybe 14 ?? You'll just have to experiment.

 

[fishfeatures]

Re: 70 hp LU bolt trouble...

I'll give it a go, I'll smack something onto it, heat it and pray that it works.

 

[racerone]

Re: 70 hp LU bolt trouble...

???------Don't like the idea of drilling, so how about a dremel grinder on each flat till a smaller socket fits.

 

[fishfeatures]

Re: 70 hp LU bolt trouble...

My drilling has a tendency to go off centre, so I think it's best to leave near as a last resort..... But I'll use the demel idea as a backup, just need to find a Dremel tool though...

 

[boobie]

Re: 70 hp LU bolt trouble...

Use mapp gas torch, not propane.

 

[fishfeatures]

Re: 70 hp LU bolt trouble...

Use mapp gas torch, not propane.

That I got mapp torch
that is

 

[boobie]

Re: 70 hp LU bolt trouble...

Don't heat the bolt. Heat the hell out of the area around it.

 

[Bosunsmate]

Re: 70 hp LU bolt trouble...

Heat the smaller size socket and then whack it onto the bolt, when it cools itl be nice and tight on there

 

[boobie]

Re: 70 hp LU bolt trouble...

If you heat the socket you might take the temper out of it.

 

[fishfeatures]

Re: 70 hp LU bolt trouble...

well i eventually got a socket on the darn bolt , and the bloody head sheared off ! now i've the shift rod disconnected, 4 bolts on the rim of the gear case, bolt under the trim tab all out and this piece of crap bolt sheared too.... and you guessed it.... the gear case won't drop, not even by a mm.

I think the corrosion around this bolt is holding it on, and due to where it runs, i can't heat it too much....

is whacking on the cav plate a good idea?? or will i start the motor and see if the vibrations shake it loose??

am coming to my wits end with this baby

 

[boobie]

Re: 70 hp LU bolt trouble...

Don't whack the cav plate. Put a bolt or two back in and leave a gap between the bolt and the lower unit. Hook up your shift linkage and start it up. Then shift it back and forth between forward and reverse.

 

[Bosunsmate]

Re: 70 hp LU bolt trouble...

Why cant you heat it much there?
Yes never whack the cav plate, they break easily.

 

[Bosunsmate]

Re: 70 hp LU bolt trouble...

Id heat it up and then whack it to send vibrations along it to break up the oxidation thats holding it in

 

[fishfeatures]

Am having no luck with this guys. Borrowed an acetylene torch and I've put heat on the bolt till it gets red, then i'll let it cool down, an no luck. I tried after getting it hot to whack it like suggested by Bosunsmate, but still no movement. I tried heating the aluminium around it and still no joy.

I'm thinking maybe it might be the driveshaft that's holding fast up into the crank...?

How hot can i get bolt before the alu will start to be affected? maybe i didn't have the heat on it for long enough, the bolt glows red for a sec or two after i remove the torch so i reckon this is hot enough.

 

[SigSaurP229]

No its def the bolt that is holding it. Spray it with PB blast let it soak for around three days. I have had good luck with these in the past. http://www.sears.com/craftsman-bolt...1x000001&kpid=00952061000&kispla=00952061000P

I also highly suggest you use a high torque impact gun the vibrations from the gun will help to loosen it. Otherwise you are going to have no choice but to drill it, I am not sure if that is even possible though as that may be a Stainless steel bolt (can't remember).