Volvo MD2020 Shaft Coupling

[steveej]

Evening All,

Hope 'Lockdown' is not making you all go insane and you are making the best of the situation.

I need to replace the Volvo dripless shaft seal on my Jeanneau SO32. I have managed to separate the shaft coupling but I am having a hell of a job getting the coupling off the shaft.

The shaft is 1 inch and the stern tube is 25mm which is a bit weird.....I can only put it down to the previous owner fitting a kiwi prop and (I believe) changing the prop shaft to imperial. Not the best idea given the seal is either metric or imperial and I have a mixture of both (Imperial shaft and metric stern tube).

Anyway, the nut that holds the coupling onto the shaft is off but I cannot get the coupling off the shaft even with pullers.




I was wondering whether there was some kind of circlip inside the coupling and then I came across this.....

Volvo Penta Exploded view / schematic Shaft Coupling, Locking Pin: 25mm MD2010-C, MD2010-D, MD2020-C, MD2020-D, MD2030-C, MD2030-D, MD2040-C, MD2040-D - MarinePartsEurope.com

which seems to suggest there is a locking pin, but I have not noticed it (and obviously can't go and check given we are in Lockdown.

The pullers are starting to damage the end of the prop shaft.



Anyone taken one of these off before. The Boat is 2003, and the kiwi prop (and shaft) installed a few years later.

Help much appreciated.

Regards
Steve

 

[Plum]

I can't see enough detail from your pictures but if there is no evidence of a cross-pin I would expect there to be a keyway, the slot of which should be clearly visible in the ends of the coupling bore, and a tapered shaft into a tapered bore. If the shaft diameter where it goes into the aft of the coupling is larger than the section that is visible after removing the central nut then it is a taper. Is that a keyway slot I can see in your first picture? To split the coupling from the taper you need a substantial puller, or, better still, a substantial bar with two holes in it that you bolt diagonally across the flange of the coupling and with a spacer between the bar and the end of the shaft. As you tighten the two bolts the centre of the bar will push on the spacer so pushing on the end of the shaft. Clamp up really tight then hit the side of the coupling with a hammer to shock and break the taper. That is what worked for me.

Www.solocoastalsailing.co.uk

 

[vyv_cox]

This page Coupling types and removal gives you guidance on the correct way to remove the coupling and many photographs of just about every type of coupling we have come across.

 

[scottie]

Having a circlip is unlikely as opposed to a taper pin which have been finished flush to the coupling body and therefor more likely to be missed the standard way to fasten a taper fit coupling is definitely a nut on a thread
1” is 25.4 mm so perhaps just bodged but???????

 

[Rappey]

A suggestion would be to drill a slight countersink type hole in the end of the shafts to stop the centre of the puller sliding off.
Some great information and how to from vyv-cox

 

[steveej]

Having a circlip is unlikely as opposed to a taper pin which have been finished flush to the coupling body and therefor more likely to be missed the standard way to fasten a taper fit coupling is definitely a nut on a thread
1” is 25.4 mm so perhaps just bodged but???????

The coupling looks like the very first photo in Vyv's link. How do you get the taper pin out?

 

[scottie]

First check which is smaller end then tap it out using a punch must have smaller diam
You may have to file the end if it has been mushroomed
Taper pin would be most likely alternatives are roll pins or straight non tapered pins that may have to be driven all the way
You need to block the shaft to absorb the blows etc
Have fun

 

[Plevier]

I had a 2003 SO32 with an MD2020 engine with the same gearbox as you have. (It also had a Kiwiprop). I had to remove the prop shaft to replace because of crevice corrosion. (There are pics of it on Vyv's crevice corrosion page in fact!)
It had a taper and keyway, no pin. I separated it with Vyv's trick of longer bolts through the coupling with a spacer - a big nut - inserted. I had to do it up very tight then belt the coupling with a lump hammer on one side with a mate holding a large weight on the other side to shock it free. I may have heated it too, not certain.
I still have the old shaft, I've just been out to the garage and looked at it to check, it's definitely just the taper and keyway.

Do you find the Kiwi overloads the engine in reverse and can only achieve very low revs?

 

[scottie]

“It had a taper and keyway, no pin”
Putting the engine into reverse would Then have the effect of 20hp trying to pull the boat back with nothing to stop the shaft coming out the coupling

 

[bristoljim]

Evening All,

Hope 'Lockdown' is not making you all go insane and you are making the best of the situation.

I need to replace the Volvo dripless shaft seal on my Jeanneau SO32. I have managed to separate the shaft coupling but I am having a hell of a job getting the coupling off the shaft.

The shaft is 1 inch and the stern tube is 25mm which is a bit weird.....I can only put it down to the previous owner fitting a kiwi prop and (I believe) changing the prop shaft to imperial. Not the best idea given the seal is either metric or imperial and I have a mixture of both (Imperial shaft and metric stern tube).

Anyway, the nut that holds the coupling onto the shaft is off but I cannot get the coupling off the shaft even with pullers.

View attachment 88685
View attachment 88686

I was wondering whether there was some kind of circlip inside the coupling and then I came across this.....

Volvo Penta Exploded view / schematic Shaft Coupling, Locking Pin: 25mm MD2010-C, MD2010-D, MD2020-C, MD2020-D, MD2030-C, MD2030-D, MD2040-C, MD2040-D - MarinePartsEurope.com

which seems to suggest there is a locking pin, but I have not noticed it (and obviously can't go and check given we are in Lockdown.

The pullers are starting to damage the end of the prop shaft.

View attachment 88687

Anyone taken one of these off before. The Boat is 2003, and the kiwi prop (and shaft) installed a few years later.

Help much appreciated.

Regards
Steve

When you have sorted out if it is pinned ,heat always helps with any coupling removal

Jim

 

[Plevier]

“It had a taper and keyway, no pin”
Putting the engine into reverse would Then have the effect of 20hp trying to pull the boat back with nothing to stop the shaft coming out the coupling

Except the big nut on the threaded end of the shaft within the coupling!

 

[scottie]

Except the big nut on the threaded end of the shaft within the coupling!
Agreed that would be correct but in this case apparently there is no thread or nut nor did you indicate that there is one on yours

 

[VicS]

Except the big nut on the threaded end of the shaft within the coupling!
Agreed that would be correct but in this case apparently there is no thread or nut nor did you indicate that there is one on yours

Thats becaus ethe OP has taken it it off

Evening All,
>
Anyway, the nut that holds the coupling onto the shaft is off but I cannot get the coupling off the shaft even with pullers..

Help much appreciated.

Regards
Steve

 

[Plevier]

Except the big nut on the threaded end of the shaft within the coupling!
Agreed that would be correct but in this case apparently there is no thread or nut nor did you indicate that there is one on yours

No - but it's in the OP's first post!

 

[scottie]

No - but it's in the OP's first post!

I sit corrected

Would not waste any more time looking for pin

Final answer!

 

[Plevier]

25mm shaft tapers to 21.5mm over 37mm length (must be 1:10, difficult to measure precisely!). M 16 thread. Keyway 7.8mm wide x 27mm long + radii.
No pin of any sort.

You must be able to see the end of the keyway in the coupling body outer end, that gives the game away! (Already said by Plum)

 

[PetiteFleur]

Years ago I had a Jaguar 27 with a Perkins Perama engine which is the same as the VP 2020 and from memory my flange had a roll pin - try wire brushing the coupling and see if there is one, perhaps hidden by paint?

 

[Plevier]

Different transmission.

 

[steveej]

yes, have inspected and no pin, just keyway and nut which I have taken off. The schematics on Marine part Europe confused me as they were showing a pin.

Cant get it off with pullers alone. It needs a whack whilst someone holds the shaft from outside the hull so unlikely to happen until after lockdown.

 

[Kinsale373]

Try again with the pullers after heating up the coupling with a blow torch , I find the small blow torches with MAP gas great for expanding and loosening seised bolts etc.

Kinslae 373