Author Topic: Replacing saildrive anode and prop removal  (Read 1634 times)

ICENI

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Replacing saildrive anode and prop removal
« on: May 03 2021, 14:36 »
I have a Bavaria 32 2003 with MD2020 engine.

I have purchased a replacement skeg anode for the boat as the old one has almost completely eroded away.

I am very concerned regarding the removal of the propeller as the retaining bolt is very badly worn!

I assume to remove the prop, one turns the bolt as though the engine is in running in reverse?

Any tips regarding prop removal when a badly fitted tool has been used would be greatly appreciated please?

paulemeier1

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Re: Replacing saildrive anode and prop removal
« Reply #1 on: May 03 2021, 18:00 »
sorry pure english but try to explain

never do this job using the engine. neither forward nor backwards.
Take peace of wood, but it between Prop and hull. Than you van do the job. Do not know what kind of prop you have, a picture may help. My'n is a volvo 3 folding. I have to losen a kind of washer which is folded round the bold. Than loosen first seal bold. if it is out loosen the bigger (24mm?) bold

If you have a simple 2 Prop, not folding I think you have to losen a bold in the middle, than you can take of the tip. than you will see the big nut

hope it helps

Fenders

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Re: Replacing saildrive anode and prop removal
« Reply #2 on: May 03 2021, 19:36 »
On our B32, 2004, MD2020 we replaced our anode and prop between lockdowns. Like Paulemeier1, we place a piece of soft wood and towels between the prop and the hull.
I can't remember whether the thread was clockwise or anticlockwise.
The photo shows the bolt which is locked in place with a toothed locking washer. (Not sure what they are called)

Hope this helps.


ICENI

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Re: Replacing saildrive anode and prop removal
« Reply #3 on: May 05 2021, 08:30 »
Thankyou.

i am concerned regarding undoing the bolt.   not the propeller itself.   As I said in my post, it is very badly worn.   i need to know if clockwise or anticlockwise to undo as i do not want to damage the bolt further!   (That is - if I CAN undo it - In that case I am in trouble!

sy_Anniina

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Re: Replacing saildrive anode and prop removal
« Reply #4 on: May 05 2021, 09:52 »
Based on my recollection the retaining bolt is RH thread, so opening counter-clockwise.

If someone has used thread-lock (even soft type like loctite 222) the bolt may seem really stuck. Applying heat to bolt head (e.g. with small kitchen-type torch) helps soften the thread-lock and also helps crack open stuck bolts because the heat expansion will slightly disturb the "stuck" thread. Some even heat&cool to cycle the heat expansion behavior before attempting to open stuck bolts.

My standard procedure is to heat & let cool at least the blade-pin retaining allen bolts in folding propeller, sopetimes I apply heat also to center bolt if it seems sticky.

BR,

Tommi
s/y Anniina

Fenders

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Re: Replacing saildrive anode and prop removal
« Reply #5 on: May 05 2021, 10:08 »
As mentioned before, we replaced our old prop with a new one.
The original had a different cone to the new one and was held in place with a bolt which needed an Allen key. Our new one has a larger hole for the bolt and toothed locking washer. Both are Volvo props of the same pitch and diameter.

As sy-Anniina says, heat is always worth a try.
If you have marine engineering at your location it might be worth chatting to them. They must have see this problem before and would probably have specialised tools for the bolt's extraction.

Fenders

SYJetzt

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Re: Replacing saildrive anode and prop removal
« Reply #6 on: May 05 2021, 12:26 »
There are several types of securing bolts for the propeller nut.
1) Bolt with allen hex key (secured with loctite or similar)
2) Bolt  with hex head, secured with fold-in teeth-washer (like on picture from fenders). This bolt has a tread-lock agent too, if fitted new.

In both cases, you have to undo the securing bolt first, which is RH tread, so undo anticlockwise. As Tommi mentioned, heat would possibly help.
If you have undone the securing bolt, you can undo the propeller nut (this is the whole cone!), with has a RH tread, so undo anticlockwise too.

If the head of the securing bolt is damaged, and can't be undone, you can:
a) Try to work a slot into the damaged head and undo with a slot-type screwdriver 
b) drill out the head. But this means you have to remove the remnants of the bolt out of the propeller shaft with a mole grip (again heat will help!!).
If the remaining lenght of the bolt is to short to catch with the mole grip, you have to remove the whole propeller shaft and drill out out the remnants. But this is usually a workshop-job.

If nothing of above: new propeller shaft :-X




Keweetoo

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Re: Replacing saildrive anode and prop removal
« Reply #7 on: May 05 2021, 13:59 »
A few sharp taps with a hammer and drift often loosens a stuck bolt (works for sail drive oil drains as well!)

ICENI

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Re: Replacing saildrive anode and prop removal
« Reply #8 on: May 10 2021, 10:46 »
Many thanks SYAnniina,fenders,SYJetzt and Keweetoo

I will go armed with a baulk of soft timber as I used to do on my last boat and I have a small kitchen type gas torch on board.

Fingers crossed I do not have to drill out the retaining allen key bolt.

Clivert

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Re: Replacing saildrive anode and prop removal
« Reply #9 on: May 10 2021, 15:41 »
Use a piece of wood between prop and hull.
Get a length of metal pipe and an Allen key and using the pipe for leverage ease the bolt out.
Did this on our saildrive under the guidance of a professional some years ago and have repeated it since

diverphil

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Re: Replacing saildrive anode and prop removal
« Reply #10 on: May 10 2021, 18:56 »
if your head bolt has rounded off, and you have the use of MiG welder, try welding a similar nut on to the head of the seized bolt, the heat will transfer down the bolt hopefully freeing any Loctite, and will give you a new hex head to get a socket on. this also works on cyl head bolts when they snap in flush to block.