Propeller shaft removal from coupling and Volvo lipseal replacement

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Moonbeam

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I'm going to replace our Volvo lipseal (it's at least 20 years old, not leaking, but has gone stiff). I have not tackled undoing the 25mm shaft from the coupling before, the picture shows the back end of the BukhDV24 on our Westerly Konsort. Has anyone encountered the coupling below? I'm assuming it's just a case of undoing the 4 x nyloc nuts on the bolts clamping the shaft? (Then sliding the shaft backwards etc.) I'm assuming they will be on tight!! I don't have a torque wrench when it comes to doing them back up... so I plan to just do them up as tight as I can? I'm replacing the lipseal with the 'Obritrade' version I have already purchased from ASAP. Any advice from any of you that have tackled this before will be much appreciated. :encouragement:

View attachment 55307

PS: I'm already looking at this https://coxengineering.sharepoint.com/Pages/Couplings.aspx
 
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Undo the clamps and then the coupling, push the shaft back, put a spacer such as a large socket in between the tail of the shaft and the nut on the gearbox output and put the coupling bolts and nuts back in. Tighten them up progressively and it should push the shaft out of the coupling. When you re-assemble make sure you locate the fixed cutter on your rope cutter properly.

BTW did you consider the Radice seal as a replacement as it has a built in greasing point and vent to avoid the need for burping.
 
Thanks for that Tranona... I did consider the Radice seal (having read some of yours and others comments on it, on this forum), but as burping the Volvo one has always been very easy due to an ingenious but very simple long arm wooden clamp that the previous owner made up to burp the seal, we decided to stay with the same type... I'd miss the ritual :)

How did you know I had rope cutter :confused:
 
For anyone with a cutless bearing in a "P" bracket - have a good look at this, it might also need replacement which you can do at the same time.
Also examine the shaft for wear.
 
Luckily our cutless bearing is still rock solid. I shall certainly get my digital callipers on the shaft to check any wear... if there is any, with luck, the Orbitrade seals might rest on a fractionally different spot than the original Volvo ;)
 
Whatever you do mark the shaft and the joint so you can match them up to reassemble. Line of felt tip marker will do.

How would I know this?

Also several votes for the Radice jobbie.
 
Consider yourself lucky that this connection is just a simple clamp and not a taper as on our Bendyboat.

I spent many unsuccessful hours with puller, blowlamp, heavy hammer before giving up and cutting the shaft in two.

I should have done this from the beginning as the shaft was badly worn where both the Volvo seal and cutless rub. Probably 12 yrs of silty water!
 
You will need to remove the bolts, I think. On Bukh installations the bolts usually pass through a small machined relief on the shaft that takes axial thrust and prevents the shaft from falling out of the coupling. Pictures of similar ones on the website.
 
Thanks everyone, all useful advice.

Vyv, I'd already gleaned that critical bit of info on the Bukh bolts from your very useful website. :encouragement: Any advice on how tight to go on the nuts without a torque wrench when putting it all back together?

Gwylan... I assume you encountered some serious vibrations upon reassemble?
 
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Tranona said:
Undo the clamps and then the coupling, push the shaft back, put a spacer such as a large socket in between the tail of the shaft and the nut on the gearbox output and put the coupling bolts and nuts back in. Tighten them up progressively and it should push the shaft out of the coupling.
Click to expand...

Be careful not to over tighten as you could break the gearbox flange!!!!
 
They are my pictures on Vyv's site. Once the bolts were withdrawn the shaft came out without too much effort, i may have used a flat bladed screwdriver as a wedge to open the coupling slightly but nothing more than that.
 
I am in the process of doing the same, I had to cut the bolts as they were rusted and un-removable. once cut I dragged the shaft out from outside after giving it one slap of a 4x2 at the base of the prop. I sprayed loads of water and a drop of washing-up- liquid on the shaft by way of lubrication.
 
Telstarr said:
Any advice on how tight to go on the nuts without a torque wrench when putting it all back together?
Click to expand...

It's something you get used to after a lifetime of putting things back together. I rarely use a torque wrench these days. Using a ring or open ended spanner that is the typical size for automotive bolts, i.e. about 6-8 inches long for a 13 mm nut and bolt (clue to my age is the mixed units!) you can pretty much tighten normal nut and bolt combinations as much as you like without fear of damage. The time to be careful is using much longer spanners with soft bolts, or with very fine threads, or where tapers are involved. Over-tightening these can cause big problems.

Edit: David Wray's photos on the website show the bolt grade to be 8.8. Not sure if these are the standard ones but you will not damage hardened bolts like these with standard spanners.
 
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vyv_cox said:
It's something you get used to after a lifetime of putting things back together. I rarely use a torque wrench these days. Using a ring or open ended spanner that is the typical size for automotive bolts, i.e. about 6-8 inches long for a 13 mm nut and bolt (clue to my age is the mixed units!) you can pretty much tighten normal nut and bolt combinations as much as you like without fear of damage.
Click to expand...

I totally agree Vyv.

My bugbear is marine and auto mechanics who just swing (or even stand!) on every spanner every time! In my experience over 50 years they give absolutely no thought to what the bolt or stud is actually for and will it be subject to lateral, longitudinal or rotational forces. Once you have worked this out and looked at the size, the thread pitch and the material both the bolt and the substrate are made from, it's not rocket science!

Richard
 
Thanks for all the replies chaps, very helpful. I hope to tackle it in the next week or so. All I need now is a half decent weather window... can anyone help with that ?!?! ;)
 
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