Prop Coupler stuck onto Prop Shaft - HELP!!!

[Spring-Fever]

I'm replacing the "stuffing box hose", which connects the stuffing box to the hull tube.

To get there, you need to detach the prop from the transmission, and remove both the coupler on the prop shaft. And the stuffing box. Slop off the old hose. Slip on the new hose. And put everything back!

Problem: The four bolts connecting the prop coupler with the matching transmission flange came off (to my surprise). I removed the square top chock screws. And tried to slip the coupler off the end of the prop shaft. NO GO!

Tried: I tried ample amounts of Liquid Wrench and WD-40. Against most advice, I tried smacking the coupler with a piece of wood and mallet. I tried heating it with a propane torch, more Liquid Wrench, then a good smack. All to no success.


Any advice is welcome!


(She's on the hard, and I can't put her in until the $11 hose is replaced. Which requires the removal of the prop coupler!)

[tkeithlu]

First thought: The propane torch is nowhere near enough heat to make a difference. Substantial steel parts just diffuse the heat too readily. You want to not just differentially expand the coupler, but also burn off the junk that is between the two. I would have used an oxy-acetylene torch with a rosebud tip.

I don't think you are going to do any damage with a wooden mallet. You might even graduate up to a brass hammer or a steel hammer with a brass punch.

[Reefmagnet]

Second the propane torch. They don't get the heat in quick enough.



The way I've done it in the past with success was to make a backing plate out of some scrap 10mm steel with holes drilled to match the coupler flange holes. Using hi tensile bolts to connect plate and flange together with and a suitable diameter socket (as in the tool) in between them, the idea is to evenly tighten the bolts whilst the socket pushes the shaft out of the the flange. You can even use the technique of tightening, wacking with a hammer and repeat more in difficult cases.

I've heard that you can do the same using the gearbox flange instead of the piece of plate, but if it doesn't want to let go there's a risk of buckling the gearbox flange, so a sacrificial piece of scrap is preferred, I think.

Other than that, if it's to far gone to dislodge, cutting the old flange off may be the only viable option (as in slitting it with a grinder so it can separated from the shaft in clam shell fashion)

[Compass790]

Reefmagnets technique should work. When you load up the bolts & give it a good bashing with a 4lb club hammer on the scrap I'd be very surprised if you cant move it.
I dont know liquid wrench but penetrol I find better than WD40. Best to have overnite soaking. Its amazing how often you have a battle with frozen stuff using heat & penetrating oil, fail, & come back the next day & it gives up easily.
Good luck with saving the coupler.

[knot smart]

Wheel puller from harbor freight. I've had to pull the hub off the shaft of our old bene 352 on a few occasions.. yes, it's a @#&!.. I got the wheel puller for less than $20 and boom. Literally a boom.. I cranked down on that thing with so much pressure, I couldn't turn it another inch by hand. And when it finally popped, the whole thing went flying off. It needs the constant pressure from the puller. And then hit it on the back side with a hammer and piece of wood. The shock will pop it off.

[wguinon]

Back off the inter-flange bolts just enough to slip a big nut between them that bears against the end of the prop shaft but not the prop flange. Then tighten the bolts up in a gradual zig zag sequence and while beating the flange with a 3# hammer. Your money back if this doesn't work.

[Spring-Fever]

These are great tips! I will try the "slip a big nut (ie socket head) between them that bears against the end of the prop shaft but not the prop flange" technique. (essentially turning the flange into a nut-puller). I'd be terrified to apply too much heat, as it is close to the hull, the stuffing box, tranny, etc.
You guys and this forum are AMAZING! I was at wits end. Thank you!

[Greg Mason]

When I had to pull my shaft off the coupler, the bolts were the easiest thing. The machine shop knew the coupler had a slice in each side to compress the coupler onto the shaft. So they made me some SS wedges to hammer into the slices, opening the slice to allow the shaft to slip out. Do you have these slices in the coupler to compress onto the shaft?

[gregorybross]

You could cut the flange coupler with a small angle grinder with a metal cutting blade. Cut one side down to the shaft then tap a metal wedge into the cut or cut both sides. Obviously you need a new coupler.

[garyfdl]

First (silly) question: is there a set screw holding the coupling to the shaft and did you take it out?

As others have said, propane is out - doesn't get hot enough. Mapp gas might work.

After that, I also vote for the oxy/acetylene torch. There is nothing to be afraid of if you adjust it properly - we're not talking a 1' flame, in fact it shouldn't even be as big (long) as the flame off the propane torch. Finding a small rosebud tip might be problematic - you can use a small/medium sized brazing tip. But... don't hold it in one spot for too long, it will melt the coupling. You have to keep it moving.

If you really don't want to use, or don't have access to the torch, try a heat lamp. But that is going to take at least a day, and you will have to insulate the shaft and build some sort of 'tent' or container to minimize heat loss around the coupling.

A puller is a great idea, if you can find one to fit. My guess is that close quarters will negate any store bought ones and you would have to fabricate something.

My last suggestion would be trying to turn the coupling on the shaft to break it loose, and then pound it off. This assumes of course that the set screw is removed along with any shaft key. Naturally you will have to find a way to lock the shaft (DO NOT USE THE PROP!). A pipe wrench on the shaft might work but will likely leave teeth marks. Another (longer - for leverage) pipe wrench on the coupling shoulder to try and turn with.

GOOD LUCK!

[Scubaseas]

MAPP gas is quicker. Leave disconnected from trans and heat, then apply PB Blaster or similar and then give it a whack with a brass hammer or drift. Most boat yards will cut the coupler off as time is money. If you can slide the shaft back far enough you can rent pullers from some auto parts stores.

Another method is to separate the flange, put in a socket between the end of the trans and the coupler shaft. The socket has to be smaller in diameter than the prop shaft. If the end if the trans is not conducive use a short socket over the trans nut, then another short socket on top of that. Get 4 good quality (grade 8 is ideal) longer bolts. Then tighten the bolts evenly. This will use the end of the trans output shaft to press against the socket, which then presses the shaft out of the coupler. Once you get it going it's easy. You will probably have to set it up, apply torque liberally then heat and tap the coupler a couple times on the edge with brass/bronze/aluminum something. It's slow but sure. Note you are not forcing anything in the transmission, just the couplers.

[nortonscove]

Pullers? This was one of the most sought after tools when we ran a boatyard.

[Minggat]

#1. This is NORMAL.
#2. NO FLAMES. NO HAMMERS.

Backing plate or trans output flange. 4 all threads 12 nuts. Spacer(s) sufficient to give you the travel you need. You might go buy nuts to stack together to do the job. Stick them together with blue tape. Press the coupler off the shaft evenly.

When you get them both in hand, (assuming you’re on the hard) take them to a machine shop to have them checked and surfaced if necessary. The face of the coupler needs to be mated with the shaft. The machinists will know.

Don’t screw with this. You can induce the effect of a bent shaft, spinning a few thousand RPM hours on end for years, or until it tells you that you got it wrong. $$$

[CAR54]

Did that job two years ago on my J28 with very little room, so no gear puller could be used.

Had success using a deep well socket a little smaller than the diameter of the prop shaft and then tightened new longer bolts using a cris cross pattern a quarter turn at a time connected between the two flanges.

You aren’t suppose to reuse the old flange do to rusting of the ID of the old coupling, so do your self a big favor and buy a split bolt coupling for the same diameter of the prop shaft. It does not need set screws or a key way, but can be ordered with a key way cut into it and is self aligning. My split coupling has been in service for two years with no problems.

I ordered it from General Propeller. They give excellent tech support and are user friendly.

PS if the old rubber tube does not come off without cutting it, you will have to grind out some material in the hull under neath where the old tube was located to get it back on.

Good luck!

[soly2]

Make sure there is no small bolts securing coupling to shaft.