slide shaft out and back in

I need to replace the rear seal on my trans. I want to do this while in the water. I need to know if i slide the prop shaft back to give me room to work will i be able to get it pulled back in? The shaft is 9' long and is supported by cutless bearings at each end. 1983 albin 36'. Has anyone done this?

You should be able to pull it back in. Much easier if you are turning the shaft as you are pushing or pulling. Check your stuffing box before you start. Some dripless won't allow the shaft to move without loosening the set screws. You may want to loosen a traditional stuffing box to make it easier.

Ted

place some sort of stop to keep it from sliding out such as another shaft zinc...

other than loosening the packing to make it easier...should be no problem.

As others have said you should be able to do it. But unless everything is aligned up correctly it can be hard to slide the shaft back and forth. Also any paint or growth on the shaft can make it difficult to push the shaft back into the exterior strut bearing. As well as moving it back into place. All that can depend on how much you need to slide the shaft back to get enough room to work. But be prepared to use a large pipe wrench or two to rotate the shaft it it's stiff.

In some cases it's easier to move it back and forth by having a diver in the water to turn the shaft by turning the prop as someone inside pulls the shaft into place. You can also use long pieces of threaded rod and nuts to pull the coupler back towards the transmission.

A zinc on the shaft is handy to have in case the shaft slips out of the coupler when the engine is in reverse. But in this case it's really not needed because there should be no reason to remove the coupling from the shaft so the shaft can't slide out passed the stuffing box. And for sure loosen the box.

Don't put a pipe wrench on the shaft! If you have to turn the shaft, put the pipe wrench on the coupling only. The pipe wrench will mark and damage the shaft and if you have to take the shaft out for some reason those marks will ruin your cutlass bearings. If you have a dripless seal, when you slide the new seal over those hack marks you made, it will not be a dripless!

Do you know for a fact that you can change the transmission rear seal once the shaft is out of the way?? I just know that in order to do the same job on my Twin Disk MG5050 I needed to completely remove the transmission and disassemble. Ended up reconditioning the whole unit while it was out.

Yes don't put the wrench on the shaft if there is any way to avoid it. I guess I thought that went without saying.

But I have been involved in cases where we had to do that and you can smooth the shaft down if you make any marks on it. It's not the end of the world or your shaft if you do mark it up.

You can also use large strap or chain wrenches to turn the shaft as well.

I replaced the seal a few years ago when on the hard. It wasn't a problem moving the shaft back because I had the prop off at the time.

My transmissions are flanged on the output end. The shafts have a corresponding flange. I drilled two holes in a short piece of flat bar that corresponded to opposing holes in the flanges. Wedge the flanges apart an inch or so, bolt on the flat bar and you have a lever to rotate the shaft back and forth while applying axial push or pull. Let us know what worked.

Yes you can move the shaft back enough to access the rear seal. I removed my tranny on the hard, but the prop was still on. There was more than enough room.

My transmissions are flanged on the output end. The shafts have a corresponding flange.

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Scribe or mark the 2 flanges before you start so they mate together (same holes) when you're done. You may not have to adjust the shaft alignment when you check it.

Shaft zincs or spurs may restrict how far the shaft can move back.

Well, I was able to pull it back but not far enough. I had a diver pull it back as far as he could. It gave me just enough room to get a 1 11/16 socket in. I think the nut had loosened up, as it should be torqued to 200 ft lbs, and caused it to leak out the splines. Since I have it apart I will replace the seal also. I may have to have the diver help get the shaft back in.

I don't get the diver part. I never experienced any problems pulling a shaft back or forth from inside. Done it on several boats. Rotate while pulling.
An old timer marine mechanic told me to put some RTV sealnt on the splines to help keep it from leaking.

AA, wish you were here to help me. That last 4" was unmovable from the inside. I originally thought the end of the shaft may have hit the rudder. Yes about the RTV, a must do.

If your moving the shaft from inside, allighnment is critical. If the shaft isn't inline with the transmission flange, the shaft may bind in the cutlass bearing(s). An inch makes a big difference.

Ted

O C Diver said:

If your moving the shaft from inside, allighnment is critical. If the shaft isn't inline with the transmission flange, the shaft may bind in the cutlass bearing(s). An inch makes a big difference.

Ted

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True but once you are out of the pilot on the flange (1/4 inch) the shaft is no longer bound by the flange, only the cutlass and weight of the prop.

jleonard said:

True but once you are out of the pilot on the flange (1/4 inch) the shaft is no longer bound by the flange, only the cutlass and weight of the prop.

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Exactly. So at that point any issues getting the shaft to turn easily (assuming the stuffing box has been loosened) may mean you have alignment issues with your bearings or perhaps you shaft is not true.

Or it could be something as simple as the shaft is binding up in the bearing do to the bottom paint or growth on the shaft.