help-how to remove prop frozen nut ???

[MitchM]

well i have to take off my prop shaft so started with the prop itself. i have a flexofold folding 3 blade prop. have gotten prop dis-assembled using reverse of their instructions for the install. piece of cake until the last big main nut: the last big retaining nut 1 1/4" diameter is inset 2" deep in a bronze hub. the whole bronze hub will slide off once this nut is freed, as according to instructions this is the last nut holding the hub onto the propshaft. 2 of us appplied about 180 ft #s ---counterclockwise to loosen -- this nut yesterday. it would not budge. tried heating it with heat gun. tried pb blaster. went and had beer. tried more pb blaster. still would nt budge after 2 1/2 hrs of messing with it.. 2 people , one holding propshaft steady 1 torquing nut with 12" extension on a 1/2" drive socket handle on a 4" deep socket on the nut....

any ideas ??? i hope this thing was n't 5200'd in place.

can't use a nutsplitter as it is inset.

i hope flexofold did not REVERSE THREAD this nut without TELLING me (as yanmar once did on an exhaust elbow joint...)

any clews , anyone ??

 

[TimCup]

Not sure about that prop-

But usually, whichever way the prop turns to drive the boat forward, that the direction to tighten the bolt (otherwise the torque of the spinning would work the nut loose). Kinda like ceiling fans- most of them turn counter-clockwise, which puts clockwise torque on the body of the fan, driving the lag screw DEEPER into the joist...


cup

ps- my experience with pb blaster has always been successful when soaking overnight... drink more beer.

 

[Allan12210]

Some prop shafts are reverse thread. Can you see any of the thread to determine the thread direction?

 

[MitchM]

well i tried to see the threads on the hub assmbly into which the big nut threads, but the nut is so flush you can't see a single thread..i think it is a rt hand prop but will check w/ boat mfgr ...

 

[RON20406]

Mitch, as long as there is no fiberglass in the hub or anything else that is flammable, get a small propane/butane torch and heat the nut. Then, take an 1 1/4" open end wrench and a ball peen hammer and give it a couple whacks. Normally, the heating of the nut will loosen any galvonic corrosion or thread goop and break the bond. The PB Blaster is an excellent product if your not too anxious, but heat and shock therapy usually do the trick. If you're successful, don't expect any congratulations from the looming men in the white coats. Good luck and good sailing, Ron

 

[Ross]

If you can get a powered impact wrench into place it should do the job.

 

[Don S/V ILLusion]

I've seen the yard guys ALWAYS use a torch. A heat gun will be useless on it. They have never failed to remove a prop yet.

 

[Maine Sail]

Try an impact gun. Also remember that once the nut is off your job has really just begun and you'll then need a prop puller to get the hub off the shaft taper. I have seen some European shafts come through reverse threaded but these are rather rare. The shaft should have a key so direction of rotation does not matter. Most all prop nuts in the US are RH thread and go on righty tighty, and come off lefty loosey.. If the shaft was built to ABYC standards it would be a RH thread but your boat is not US built so all bets are off.

 

[Don12364]

Slog It

I have seen fitters do as they say and "slog it".
Before putting heat on to anything and possibly softening by annealing the nut, shaft or prop I suggest reassembling the blades back on to the prop to give it some inertia. Then put the wrench back on the nut and then give it a few healthy whacks in the unscrewing direction with a decent sized hammer.
Don't go mad but what you are trying to do is to generate an instantaneous impact torque which is many times that which you could apply under static conditions.
You should be able to see if anything moves by the position of the wrench handle to the blades.
If you do not move it try some more whacks in the tightening direction before reverting to the unscrewing direction.
If you cannot see any exposed thread to determine LH or RH thread look closely at the end of the shaft where the thread finishes and you should be able to make out the very end of the threads.

 

[MitchM]

update on the frozen nut: prop shaft was indeed manufactured with 30 mm diameter to ISO4566 taper standards, left counterclockwise direction to loosen, as is standard on this ISO. (that is also ABYC which many euro manufacturers also a dhere to...) so i pb blasted it again left it overnight went to a good mexican restaurant for some coronas. the next am then put prop blades back on. (great tip thanks...) then got a piece of wood between a prop blade and hull, and jammed a blade against the piece of wood and made sure the blade would not turn so the prop was fixed when i torqued the nut left to loosen it . got a 24 inch breaker bar and a 30 mm deep socket to match the 30 mm nut (which i thought was a 1 1/8 "" o well.. ) so the nut came off. then i used my brand new flex o fold prop puller to pull off the prop.. next i will use my brand new strut pro cutless bearing puller/removal tool to pull the cutless bearing,

stay tuned for the excitement when i remove the propshaft.. from its flexible coupling, which is the subject of another thread...

all in all -- with advice from this board, i figure i have saved $1000 in mechanics FEES. (since i am a closet tool junkie i do not count the cost of any tool i need into a repair job, tool buying is the equivalent of a 'shopping trip to the mall' for us junkies. )so if youns are near erie PA stop by presque isle marina look for the eagleswing -- the beer is on me. with lime if ya want.

 

[Ross]

After all of that you have some new knowledge and some new tools. Both will be far more valuable than money.

 

[sailaway78]

Unless necessary

Unless there is a particular reason to remove the prop, I wouldn't. It isn't necessary to remove the prop in order to pull the shaft. So, unless there is a strong reason to remove the prop, just leave it on the shaft and pull the shaft. Can save a lot of cuss words and hard labor, leaving more time for the Coronas.

 

[Alan]

If you've got a cutless bearing removal tool, why then do you need to remove the shaft? After pulling the prop the bearing can be removed and installed with the shaft in place.