Removing prop shaft coupling pin

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Minerva

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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? IMG_0081.jpegIMG_0084.jpeg
 
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.


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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.
 
Boater Sam said:
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.
Click to expand...
It is NOT a grub screw, it is a roll pin.
 
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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
 

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mrangry said:
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
Click to expand...
Have you not read all of the other replies ? It is NOT an allen screw.
 
On my Moody I had the roll pin in a roll pin coupling. After it was removed and the gland replaced by an engineer, he used a bolt and locknut to replace.
 
ithet said:
On my Moody I had the roll pin in a roll pin coupling. After it was removed and the gland replaced by an engineer, he used a bolt and locknut to replace.
Click to expand...
That's wrong. The roll pin is a tight fit, but acts as a sheer pin if something is picked up around the prop, nuts and bolts don't work the same.
 
Don’t you need something rigid and heavy under the coupling to act as an anvil and then hit the roll pin punch ( make sure it’s the correct size) with the biggest hammers you can find.
 
PaulRainbow said:
That's wrong. The roll pin is a tight fit, but acts as a sheer pin if something is picked up around the prop, nuts and bolts don't work the same.
Click to expand...
Island Packet use a 3/8th bolt paul. Not HT by the markings on the head, but it would take some shearing! A 1/4 x1/4 square key and the 3/8th bolt is the coupling drive mechanism. All IP's are the same AFAIK. It is the standard Yanmar coupling, modified by IP at build.

Never gave me any qualms. It needed a set of 4 longer bolts and a 25mm socket popped in the gap and the bolts tightened to press the shaft from the coupling, it was bloody tight.

I know it is a different type of coupling, but mine had no shear safety device.
 
rotrax said:
Island Packet use a 3/8th bolt paul. Not HT by the markings on the head, but it would take some shearing! A 1/4 x1/4 square key and the 3/8th bolt is the coupling drive mechanism. All IP's are the same AFAIK. It is the standard Yanmar coupling, modified by IP at build.

Never gave me any qualms. It needed a set of 4 longer bolts and a 25mm socket popped in the gap and the bolts tightened to press the shaft from the coupling, it was bloody tight.

I know it is a different type of coupling, but mine had no shear safety device.
Click to expand...
Mine looks the same as the OP. No key, it's secured by the pinch bolts and the roll pins, 13mm with an 8mm through the middle. Picked a line or something up at the end of last season and it sheared both roll pins and turned the shaft in the coupling!
 
I'm with PaulRainbow on this, mine exactly the same with the double roll pin, I had a right fight with one of mine a year back to the point I was ready to cut the shaft and replace when it finally gave in, a very well sized drift is required or you will peen the end of the pin and be well stuffed, shift the inner pin first don't try to shift both together.
 
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