Worst Case scenario for Seized Coupling?

[Jarod]

hello all

I was attempting to remove my shaft coupling today and long story short i now have 3 rounded over bolt heads. These suckers are seized on there tight and there is a signficant amount of rust involved. I ended off the night grinding off one of the bolt heads as i figure this is my only recourse at this point. The plan is to grind off the bolt heads ...drill out the keyway try and separate the shaft coupling and output flange in this manner. The boat has an atomic four not that this really matters as all couplings are more or less the same.....just for reference sake no this is not a split coupling. If anyone has any thoughts suggestions that might help out I AM all ears. I have a replacement coupling on hand so not worried about sacrificing the old ball of rust.

thanks jarod

 

[Guy Stevens]

Split the coupling

I have used a dremel tool with a cutoff blade, the new ones that are bigger work better. Reinforced of course. Cut the coupling lengthwise where it is mated with the shaft. This is about a 3" or so long cut. Do not cut through to the shaft, leave a 1/8 or 1/16 of a inch of the metal before you would cut into the shaft.

Then smack it with a cold chisel.

Alternately if you are on the hard, cut the shaft off, get a new shaft.

Guy

 

[rwthomas1]

I have used the Dremel that Guy mentioned with great success but it can take a while and use up a lot of the reinforced cutting wheels. To speed up the process the bulk cutting can be done with a 4 1/2" angle grinder with a cutting wheel and then finished with a Dremel. Its gonna be a nasty, dusty job and sparks will fly so take precautions. Wet towels work well. RT

 

[hodo]

If you cut over the keyway, you have less material to remove, and less chance of damaging the shaft. You will see a different color of sparks if you hit the stainless. When re assembling use lanacote or some type of anti-seize.Wear eye protection, the little device they use to get the metal slivers out of your eyes is quite unplesant. Good luck, Harold

 

[Jarod]

Hi guys

Well i cut my shaft just aft of the stuffing box as i needed the room to work. The shaft replacement is the least of my worries now as i have ground off the heads on the bolts and this coupling still won't budge. I have tried a bit of liquid wrench and tried to open a gap between the shaft coupling and the output coupling with a chisel, but no cigar....what am I missing here i would think once the heads were ground off the three bolts the shaft coupling would separate from the engine without too much resistance....please let me know if any ideas come to mind.

thanks jarod

 

[Emerald]

Hi,

you say three bolts. Every A4 I've seen has 4 bolts. Yours could be different, but double check for that 4th bolt. I know, it seems impossible to have missed a 4th, but....

 

[tenders]

Hi,

you say three bolts. Every A4 I've seen has 4 bolts. Yours could be different, but double check for that 4th bolt. I know, it seems impossible to have missed a 4th, but....

My A4 has 3 bolts--standard on V-drives and some other configurations having to do with reduction gears, I think.

The Dremel is too dainty for removing couplings that are beyond hope. My tool of choice is the Sawzall--especially if the shaft is to be sacrificed to the corrosion gods as well. (And shafts, in the grand scheme of things, are relatively easy and inexpensive to replace.)

 

[CaptDan]

Hi guys

I have tried a bit of liquid wrench

You might try PB Blaster squirted between the coupler and shaft. Force as much of it in as you can, and let it seep in over night. Then, tap the coupler with a hammer - fore and aft to get it to break free.

An old mechanic I knew used to make up a 'cocktail' of PB Blaster and Liquid Wrench; the juice worked wonders on some of the most stubborn rusted parts.

Good luck.

Capt Dan G>E35II "Kunu"

 

[Emerald]

My A4 has 3 bolts--standard on V-drives and some other configurations having to do with reduction gears, I think.

Interesting. Bolt configuration must have been luck of the draw. Just rebuilt one with a Paragon drive reduction that was 4 bolt. Just when you thought it was safe to go outside...

 

[Martin King]

Jarod,
You didn't say if you got the bolts out. If not, take a drift pin and try
to tap them. If they wont budge you might try soaking them with
Kroil overnite. That stuff works better than anything I have ever used
for rusty parts. If that doesn't work, the next step would be a torch
on that coupling. Stay away from trying to drive a wedge between
them.

Martin

 

[Jarod]

Martin

No i was not able to remove the bolts. I ground the heads off and yet the shaft coupling still clings to the output coupling. There is no real access to hit the remaining bolts with anything. I just returned from the boat and was able to make some progress with a sawzall. I made three cuts as suggested above in a triangle essentially inside the circumferance of the bolts and I am nearly to the mating surface of the output flange. If i cut into the output flange a bit will this be ok? I am thinking I should just try and get close then finish with a hacksaw. Of course as always everything is much harder than it sounds due to limited access.

 

[Martin King]

Jarod,
Cutting inside the bolt holes should work. Try not to nick the output
coupling.

 

[Jarod]

I hope so Martin and thanks for the advice everyone. One thing about boats at least I end up getting alot of new tools...like the sawzall. I hope today brings some resolution...dont want to pull that motor.

 

[tenders]

My output coupling does have a few Sawzall bites on it, I admit, apparently to no deleterious effect. But it would be better to have hacksawed the last few microns out instead.

 

[Jarod]

It was an ugly job but i got it off ...just wanted to let everyone know and thanks again for the suggestions they really helped