Removing prop shaft coupling pin

[Minerva]

One of the tasks I would like to do before launch is replace the rubber tube on the sterngland.

I’ve managed to loosen all 4 tightening bolts on the coupling easy enough. The issue is the pin - i spent yesterday offering various forms of encouragement but got no movement at all.

I am confident I’m going at the smaller side of the (presumably cone shaped) pin.

So far yesterday I’ve used
1)punches/drifts using a normal sized hammer
2) penetrating oil
3) blow torch
4) a file to ensure it’s not mushrooming and binding.
5) drill - snapped two drill bits

And despite quite a lot of effort yesterday I got it to budge not a fraction of a mm.

I could use a larger lump hammer, but I don’t want to damage the gearbox.

The only suggestion I have left is tighten the bolts back up to see if they take some pressure off the pin and allow it to move.

So - any other suggestions?

 

[PaulRainbow]

It's a roll pin inside of another roll pin. It is straight sided so you can punch it out from either side. It is very hard, you will not be able to drill it. You need to punch the small pin out first. Put the bolts back in first.

 

[Boater Sam]

It should be a grub screw! So you will get nowhere unless you get it to unscrew. Dremel a slot in the top, soak it for days in penetrating fluid, not WD40, and hope that it unscrews
Judging by the rust everywhere you need to think about some serious stern gear renewals.
If all else fails, take an angle grinder and cut the 1/2 coupling apart, fit a new one.

 

[PaulRainbow]

It should be a grub screw! So you will get nowhere unless you get it to unscrew. Dremel a slot in the top, soak it for days in penetrating fluid, not WD40, and hope that it unscrews
Judging by the rust everywhere you need to think about some serious stern gear renewals.
If all else fails, take an angle grinder and cut the 1/2 coupling apart, fit a new one.

It is NOT a grub screw, it is a roll pin.

 

[vyv_cox]

There is a case history of exactly the same problem on my website at Coupling types and removal

Definitely a roll pin. Knocking out with a punch is the normal removal method but it might be possible to make a puller/pusher if access is very tight.

 

[Poignard]

Use a roll-pin punch in preference to a plain punch. Less likely to break the pin.

 

[Tranona]

screwfix.com/p/forge-steel-pin-punch-set-8-pieces/936xg

Once you get it apart worth considering replacing the coupling with something more modern as well as fitting a non drip seal to replace the stuffing box. A Volvo type seal is not a lot more money than a replacement hose lakesterngear.co.uk/catalogue.pdf couplings, seals and hoses here for example.

 

[Minerva]

screwfix.com/p/forge-steel-pin-punch-set-8-pieces/936xg

Once you get it apart worth considering replacing the coupling with something more modern as well as fitting a non drip seal to replace the stuffing box. A Volvo type seal is not a lot more money than a replacement hose lakesterngear.co.uk/catalogue.pdf couplings, seals and hoses here for example.

That is the exact punch set I bought yesterday!

 

[mrangry]

On my Yanmar coupling which looks the same as this it was a threaded allen locator screw from memory which located in the keyway in the end of the shaft as pictured.

Sorry forget that, just looked again at this further image and the allen screw located in the small indent