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Failed to remove the shaft coupling

Lucas Gan

Active member
Joined
5 Oct 2018
Messages
414
As I am going to replace my staffing box. One of the challenges is to remove this shaft coupling to withdraw the shaft. This is my port side shaft. I can not make any movement at all by using a puller and tie the puller to the maximum strength. The shaft is 45mm diameter. Any advice? Many thanks.
Screenshot_20210715-170919~2.png
 

OBB

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12 Jul 2021
Messages
13
A few hefty knocks with a copper mallet to shock it loose whilst under tension from the pullers.
 

oldgit

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6 Nov 2001
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24,083
Location
Medway
After making sure you have located and removed ALL the grub screws............Heat with gas torch .
Personally would be using a decent hydraulic puller.
Your puller looks like it would have problems removing the skin from a rice pudding. :)
It might let go with bang so do not stand directly in front.
 
Last edited:

Bandit

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30 Jun 2004
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3,275
Location
Guernsey
Your shafts will be 1.75 inch.

A bigger puller, wind it well up and apply heat and leave it overnight.

Last resort cut it off a very messy job.
 

Lucas Gan

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5 Oct 2018
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414
Okay. I am going to buy a 10 ton hydraulic puller now. Hopefully strong enough to do the job.
 

AndieMac

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24 Mar 2009
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Tasmania, Australia
Hi Lucas
You seem to have threads going all over the homepage with the similar issue?
Might be helpful for those responding to bundle them into one.
 

oldgit

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Medway
looking at the pix the shaft and flange are like new, you should have no trouble pulling of the flange with any decent puller.
You can always hire one rather than buy.
 

Lucas Gan

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5 Oct 2018
Messages
414
I am stuck. I still can not remove the coupling after bought two hydraulic pullers 15 tons and 10 tons. Because the centre pole of the 15 tons hydraulic pullers can't even long enough to reach the shaft when it extends to the maximum length! The 10 tons one can barely just reach to the shaft while maximum length but more strength, not even making any movement. They are just not fit to pull something like this small and thin. Any idea what puller can fit this job? Many thanks.

Screenshot_20210720-155521.pngScreenshot_20210720-155438.png
 
Last edited:

ctva

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8 Apr 2007
Messages
3,802
I made a diy puller which worked first time I put it on. pics attached, basically 10mm plate drilled for the four mounting bolts and the centre one tapped and a point put on the end of the middle bolt. Then just tighten each of the four bolts in turn. No heat required.


I take it you took off the securing nut on the end of the shaft.

IMG_5285-001.JPG

IMG_5284-001.JPG

IMG_5286-001.JPG
 
Last edited:

Croftie

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19 May 2015
Messages
519
Can't you put a spacer block between the shaft and the puller
 

Lucas Gan

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5 Oct 2018
Messages
414
The engine room is very tight. The shaft coupling at the end of the engine room. I can only get one hand in there to operate, can't even put two hands in! The pulley is a million kg in weight, it's not possible I could put a spacer in between. I already reattached the coupling back to the gearbox. I might get it off from the gearbox again and try to heat it, small puller and hammer it to see if any luck.

I feel just a little hope to make the coupling off as I see the shaft there is not in cone shape at the coupling end. It's just exactly 45mm in diameter at the coupling end. So that means it is not likely will pop up in a click. It is most likely need a hard pulling a little by little through the whole coupling length which is more than 10cm long!
 
Last edited:

burgundyben

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28 Nov 2002
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6,574
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Niton Radio
If I understand correctly, shaft is parallel not taper?

If its really stuck on hard, are you sure you got all the bolts or pins or grub screws out?
 

Restoration man

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3 Jun 2012
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oldgit

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6 Nov 2001
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Medway
I have several short pieces of ex stainless propshaft about 50mm in length to allow end of puller to apply pressure to end of prop shaft.
 

Lucas Gan

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5 Oct 2018
Messages
414
I am going to give it one more try today. The plan is to replace the tiny puller legs with the 10-ton hydraulic puller to make them shorter. Then put a socket between the puller and shaft when needed.
 
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