How to pull the prop shaft out a bit?

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seumask

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In order to replace the shaft seal on the vetus stern gland I need to slide it off the front end of the prop shaft. The prop shaft is clamped to the anti-vibration mechanism on the back of the gear box. I have loosened the clamp bolts and tried to pull the shaft out by grabbing the prop and heaving whilst leaving the engine in gear. So far no result. It looks like I may need to hammer the prop shaft out of the clamp. Clearly I can’t get at the engine end of the shaft and will need to put some effort through the prop end. What methods does the forum suggest, trying not to damage anything!
NB this is a Westerly Fulmar bilge keel with a standard P bracket and plenty of room from prop to rudder.
 
DON'T hammer the shaft whilst it's bolted to the gearbox. That's an excellent way of ruining output shaft bearings in the box.
There are various , kinder ways, illustrated on Vyv Cox's website.
What type of coupling is it?
 
earlybird said:
DON'T hammer the shaft whilst it's bolted to the gearbox. That's an excellent way of ruining output shaft bearings in the box.
There are various , kinder ways, illustrated on Vyv Cox's website.
What type of coupling is it?
Click to expand...

Thanks for the mention. Here is the link.

'Never hammer a boat' is an excellent motto to pin up in your saloon. I would suggest it to Nauticalia but I doubt it would catch on. There is nothing in the average boat that will benefit from being hammered. You might get away with it many times but something expensive will be damaged in the end.
 
As indicated elsewhere your shaft coupling IS a puller, take out the plastic component, put coupling halves together with a spacer, ie socket, between the shaft end and forward coupling half, and tighten bolts evenly, socket will push the shaft out of the coupling.
 
Check that there is not a grub screw locking the clamp onto the shaft. Even if there is not, the shaft can take some shifting. Undo the coupling bolts, push the whole shaft and coupling back, insert a spacer such as a socket to bear on the end of the shaft, replace the bolts and slowly tighten. You should find it slides easily once you get it moving.
 
Thankyou for the link to Vyv's site, I now see that I have A R&D Marine flexible coupling with a A Bukh shaft coupling. According to the Vyv's site "Axial retention of the shaft is achieved by grooves in way of the coupling. The shaft cannot be withdrawn until all bolts have been removed." So I need to remove all the bolts not just loosen them. Still wondering how the shaft might slip out of the Bukh Shaft coupling does this need any "help loosening"
 
You won't know until you try it. The shaft slid out of my Bukh coupling with no effort at all but in other cases it can be quite difficult to get them apart. In that case use the method on the website, undo the flange bolts, put a packer between the shaft end and the gearbox flange and put a couple of flange bolts back. Two is usually enough.
 
vyv_cox said:
Thanks for the mention. Here is the link.

'Never hammer a boat' is an excellent motto to pin up in your saloon. I would suggest it to Nauticalia but I doubt it would catch on. There is nothing in the average boat that will benefit from being hammered. You might get away with it many times but something expensive will be damaged in the end.
Click to expand...

Oh I don't know. Once in a while on my boat I think the general state of the universe could benefit from my getting well and truly hammered! :) :)
 
seumask said:
Thankyou for the link to Vyv's site, I now see that I have A R&D Marine flexible coupling with a A Bukh shaft coupling. According to the Vyv's site "Axial retention of the shaft is achieved by grooves in way of the coupling. The shaft cannot be withdrawn until all bolts have been removed." So I need to remove all the bolts not just loosen them. Still wondering how the shaft might slip out of the Bukh Shaft coupling does this need any "help loosening"
Click to expand...
Ah, the Bukh coupling - Yes all 4 blots need to be removed completely from the coupling as they sit in grooves machined into opposite sides of the shaft. When I did mine for the first time I culd not free the shaft even after removing the bolts - problem over come by gently driving a couple of steel wedges into the slots on the coupling - not the word GENTLY! (1oz "toffee hammer" held between thumb and forefinger). Each time since that I have managed to remove the shaft by removing the 4 bolts and giving the side of the coupling a gentle tap (holding a heavy steel weight on the opposite side).
A word of caution - mark the coupling before removing it from the gearbox output coupling so you put the coupling back together in the same orientation - I had a little vibration in mine until I turned the shaft side of the coupling 180°. I am not sure why this should matter :confused:
 
not a big fan of the hammer myself - but I do keep two around, perhaps I should get rid!

Although the same bukh coupling as on vyv's website, mine has threaded holes on the shaft flange, the studs feed in from the gearbox flange. Vyv's pic shows a nut & bolt arrangement.

so not alot of room to get a longer studs in there on my version.

an awful ball of rust - I could only get 5 of the 6 flange studs out so I couldn't split the coupling anyway. Spent half a can of penetrating oil on the shaft half-coupling over two days. Slightly greater than gentle tapping on the rear of the propeller got the shaft out - should have got the steel wedges perhaps.
 
seumask said:
Thankyou for the link to Vyv's site, I now see that I have A R&D Marine flexible coupling with a A Bukh shaft coupling. According to the Vyv's site "Axial retention of the shaft is achieved by grooves in way of the coupling. The shaft cannot be withdrawn until all bolts have been removed." So I need to remove all the bolts not just loosen them. Still wondering how the shaft might slip out of the Bukh Shaft coupling does this need any "help loosening"
Click to expand...

The pictures of the Bukh coupling on Vyv's site are from my boat, a couple of thin metal wedges did aid removal (think I used bricklayers pins), I also sprayed some plusgas / WD40 down the slots and left it to soak in over lunch. The coupling them came apart easily without the need to split the coupling and push the shaft out with the aid of a socket. I would recommend new nylock nuts (or split washers) on replacement.
 
Lots of good stuff here, and methods to use to separate the bukh prop shaft clamp. There is a little rust on mine but I dont think it will be too difficult to get apart as the 4 cross shaft bolts loosened with hand tools under normal pressure. It’s this weekend’s job so I'll report back if I'm not successful. Thank you all.
 
Prop shaft came out very easily once I had removed the bolts from the Bukh clamp. More intresting was the scale that was on the prop shaft causing the seal to drip. Has anyone else seen what I can only describe as scale like you find in a kettle on thier prop shaft, fairly soft and could be scraped off with a finger nail or a scouring pad. I can't think of any obvious solution to preventing this scale build up.
 
In or out of the water? If out of the water then:

1/ spray with release fluid and leave for a bit
2/ put the engine in gear
3/ go to the stern and turn the prop by hand against the resistance of the engine. As you turn it, pull.

If its in the water then the first thing to do is to put a circlip round the shaft to avoid any risk of it popping out completely when released. Then

1/ tap a wedge into the split in the coupling. Dont go at it bull headed but firm taps along the line of the shaft arent going to damage bearings.
2/ If necessary separate the coupling from the engine and put a socket between the end of the shaft and the coupling at the gearbox. Then using longer bolts, re -tighten so that the shaft is forced out of the coupling
 
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