Dodgy prop nut stuck fast - help pls

[the gecko]

Im sure someone in the AF brains trust has come up against this before......

Im changing my prop and the locknut is stuck fast. Ive removed the split pin, and covered the nut in WD40 a few times. It was a bit rusty, so Ive cleaned it up with a wire brush. But when I try and loosen the nut, Im just starting to 'round it off' a bit. I thought I better stop and ask for some advice before I damaged the nut even more.

Ive tried a socket, ring spanner and open end spanner, and all of them slip a bit when I tap em with a hammer, and the nut is getting a bit rounded now. Theres still enough meat left on it to get a grip, if I can loosen the nut somehow.

Is heat treatment my next option? I might buy a butane torch from bunnings....

Any other ideas guys?

Ive got a new nut kit on order, so I just need to get the old one off. Ive never done this before.

Oh, its a Johnson 35, the 3 cyl model from 96.

TIA
Andrew

[tunaticer]

Might be worth investigating a nut splitter to save the gearbox shaft maybe. I have seen two types, flat and an inline one that goes over the end of the bolt. The latter one will probably be your best chance. It basically forces a hardened wedge into the flat of the nut either splitting it or stretching it depending on the hardness of the nut.

Good tool shops will be able to source them, definitely not places like bunnings though.

I would not entertain the use of heat in this location, the repair bills could be large.

Is it a stainless nut on a stainless shaft?? If so it is most likely severely galled and a nut splitter would be your only chance without badly dmamging the shaft.

[DR]

a really silly comment, but all suggestions may help others, the thread is not the opposite what you are trying is it???:-/

[snasman]

a really silly comment, but all suggestions may help others, the thread is not the opposite what you are trying is it???:-/


exactly what I was going to ask.

[FNQCairns]

I would leave heating alone, you could try a freeze spray but it's hit and miss. What about a dremil if you run a couple of cuts deep but not all the way down to the thread then use a spanner or socketit will distort the nut to the point it may just fall off or wind off.

cheers fnq

[trueblue]

the nut should not be rounding like that if the tool fits properly.

Given the rounding damage that already exists, one last chance for removal with a tool would be to buy a 6 point socket that fits properly. These are typically impact type sockets, but they work extremely well in this situation because they don't slip.

to get the correct size you will have to measure an undamaged part of the nut flats with a vernier caliper. Due to the damage, it would need some dressing to get a 6 point to fit on again, and will probably need a tap over the end of the nut with a hammer to get it all of the way against the washer.

Use a long breaker bar (450 mm) with the smallest possible extention so that you ensure the breaker bar is working at 90 degrees, but is not too long.

Most nut splitters won't get in to that tight space, and the remaining option is to grind off the nut without damaging the shaft thread, and there is a real skill to that.

I wouldn't heat the nut unless an outboard mechanics suggests it as a good idea.

[385EXPLORER]

Use a single hex socket like trueblue suggests,If u can see rust,I'd try a better quality rust spray like Inox or wurth rost off,let it soak,grab a six pack and ya boat,head to your local tyre shop or mechanic and swap your sixer for a lend of a rattle gun,hold ya prop blades with a rag and zap.don't forget to check for reverse thread.

[Roughasguts]

Grind a slot in it with a dremmel or similar, that part will then stretch or break off when loosening the nut.

[Benny01]

the shock off rattle gun will whip it off easy. you did a good job on that nut. looks like somethings had a chew on it

[PinHead]

Im sure someone in the AF brains trust has come up against this before......

Im changing my prop and the locknut is stuck fast. Ive removed the split pin, and covered the nut in WD40 a few times. It was a bit rusty, so Ive cleaned it up with a wire brush. But when I try and loosen the nut, Im just starting to 'round it off' a bit. I thought I better stop and ask for some advice before I damaged the nut even more.

Ive tried a socket, ring spanner and open end spanner, and all of them slip a bit when I tap em with a hammer, and the nut is getting a bit rounded now. Theres still enough meat left on it to get a grip, if I can loosen the nut somehow.

Is heat treatment my next option? I might buy a butane torch from bunnings....

Any other ideas guys?

Ive got a new nut kit on order, so I just need to get the old one off. Ive never done this before.

Oh, its a Johnson 35, the 3 cyl model from 96.

TIA
Andrew

forget the butane...they only give about 2000C and quite a large flame spread..the heat treatment will work but you will need an oxy set and directly on the nut...get the heat anywhere else and you just expand that also. Heat the nut quickly then lay into it with a correct sized socket on a long bar.

Another option as someone else said..liquid nitrogen on the shaft to freeze it.

OR...impact rattle gun

[Spaniard_King]

Is a Brass nut, get the Missus hair dryer and warm/heat it up. Jam the right size single hex socket on it..lock the prop up against the geacase with a peice of timber then use the longest breaker bar to undo it.

Fom Memory should be 13/16 that nut.

[the gecko]

Is a Brass nut, get the Missus hair dryer and warm/heat it up. Jam the right size single hex socket on it..lock the prop up against the geacase with a peice of timber then use the longest breaker bar to undo it.

Fom Memory should be 13/16 that nut.


Its an 11/16 size, and yes, its not reverse thread, I had checked that. I have jammed the prop against the shaft already. Perhaps the sidchrome sockets and spanners are not getting proper grip, I was wondering about that.

The guys at Solas who sold me the prop suggested a butane torch, but i might leave that alone for now. The hair dryer is an interesting idea. If that doesnt work, I might look at the calipers and a new type of socket.

Thx guys, I will work on it over the weekend, and report back.

cheers
Andrew

[GBC]

Take the boat to the boatshop (Mayne's near the airport ???) Matt'll get it off. Prolly cost you $20.00. Money well spent at this stage of the game I'd think.

[the gecko]

Take the boat to the boatshop (Mayne's near the airport ???) Matt'll get it off. Prolly cost you $20.00. Money well spent at this stage of the game I'd think.

I think thats a good call. By the time i buy calipers and a hex socket, I might as well let a pro do it. hes getting the nut and washer kit in for me next week, so I might drop of the boat too. he did my service not long ago, so he shouldnt mind this small job.

[trymyluck]

I think thats a good call. By the time i buy calipers and a hex socket, I might as well let a pro do it. hes getting the nut and washer kit in for me next week, so I might drop of the boat too. he did my service not long ago, so he shouldnt mind this small job.

Hi all
Just one comment, and maybe I expect more then i should but wouldn't part of a service involve removing the prop. The old man used to do all his own services but never bothered with removing prop to lubricate the prop shaft until I had to cut his prop off with a angle grinder.
Mark

[Fishbait]

Agree - the prop should have been taken off at the last service.

[GBC]

staino on staino will gall at any time - lets not shoot the mech just yet fellas.

[Roughasguts]

The prop nut should only be finger tight anyway, that be why she has a split pin.

If your worried about the prop nut, being finger tight only and a split pin!! the only thing holding your prop on!

Then you better not think about your wheels on your car and trailers, same thing finger tight and a split pin holding them on.