Dripless donut stuck on shaft

[abarrow]

I need to remove my reverse gear unit while the boat is in the water, so first step is to move the prop shaft back. I have a dripless shaft seal.

I loosened the set screws until they are almost out, my plan being to push the shaft back while sliding the donut, keeping some pressure on the shaft seal to prevent too much water from coming in.

Donut doesn't move, not even a little! I tapped it a bit with a small hammer, even clamped it on the outside with very large pliers and tapped that backwards. Not a trace of movement. It is stuck.

So, some considerations:
- I don't want to put something on the water side of the donut, for fear of marking it and creating a place where the seal could leak.
- Heat it? I'm concerned I might damage the rubber boot.

I was thinking maybe getting a big C-clamp on the outside of the donut, clamp it down, then see if I could hit the clamp with a hammer in the direction I want the donut to move.

The shaft and the donut are very clean - no sign of corrosion. The prop shaft was replaced about 4 years ago. I guess it's possible in engineering the new prop shaft the tolerances weren't what they should have been and it is slightly too big for the donut. Just speculation.

Does anyone have any ideas on how I might get this darned thing to move?

[noelex 77]

If it is a PSS seal they have two sets of set screws. The top set just act as lock screws to prevent the lower set which actually do the holding from loosening.

You need to completely remove the first set then you can loosen the second set lying underneath.

When replacing you should use new screws as the point becomes deformed.

[abarrow]

Dohh!

A great case of ignoring the obvious. Somewhere in the back of my mind I knew they had stacked set screws, but...

Oh well, I'll just walk away in my embarrassment. Thanks.

[SY Harmony]

Besure to secure tension on the boot when the trans is out.

[tkeithlu]

Hey, abarrow, no need to be embarrassed. When the solution didn't come to mind, you asked for help rather than destroying the whole thing with a bigger hammer. That's what the forum is here for.

Next time you'll respond to someone saying "I had that problem once...."

[noelex 77]

Originally Posted by abarrow

Oh well, I'll just walk away in my embarrassment. Thanks.

That is what the forum is for. Everyone who has worked on boats for long enough has banged away on a part, only to discover a hidden bolt that needs to be removed.

Glad this one could be sorted out easily.

[gonesail]

you're doing that in the water? i thought about it but ended up hauling the boat. needed new shaft anyway.

[MicHughV]

Yep, those donuts have two set screws on top of each other....crafty buggers....the shaft itself may also be indented to accept the first set screw, so when you move it, make sure to move it back in the same place at the same angle, otherwise the first set screw won't seat properly.

[wrwakefield]

Since you need to keep the dripless bellows compressed while working in the water, consider using a collar shaft anode against the SS PYI Collar. That way you don't have to keep buggering your prop shaft with the set screws.

We keep an anode on the shaft as a back-up to the SS compression donut (in case the set screws ever slipped.)



And you can modify a collar anode by drilling two holes through it parallel to the drive shaft. Either tap the holes for a small diameter bolt (e.g., 1/4-20) or use a nut and washer on the thrust side. By tightening the anode in place with the two bolts touching the SS donut, you can turn the bolts to compress the bellows, then insert the set screws. When finished, remove the two small bolts from the anode and slide it up next to the SS donut as a back-up.

Image courtesy AAC.

In case any of this is useful.

Cheers, Bill

[abarrow]

Great idea! Thanks.

[RSB333]

Hi, I was told that I should replace the rubber boot because it's fully compressed against the hull opening. Your picture shows your rubber boot almost fully compressed.
Is this a sign it's time to replace the boot?
RSB333

[abarrow]

I don't know about wrwakefield, but in my case, my mechanic told me that I'd need to replace my boot next time the boat is hauled, as it was quite compressed.

[wrwakefield]

Originally Posted by RSB333

Hi, I was told that I should replace the rubber boot because it's fully compressed against the hull opening. Your picture shows your rubber boot almost fully compressed.
Is this a sign it's time to replace the boot?
RSB333

The Type A PSS Nitrile boot in my previous photo (post #9, above) was taken right after installation of a new bellows: compressed to the manufacturer recommended 1 inch for my 1-3/4 inch shaft per their installation instructions.

Unless it is leaking, physically damaged, or you have had to compress it beyond factory specs to prevent leaking, there is no way to visually determine if the bellows needs replacing that I know of.

These Type A Nitrile boots are thick and tough, but I replace them about every 6-8 years during a routine maintenance haulout (per manufacturer recommendation.)

For comparison, attached is a photo of one I replaced after 8 years (left in photo; without hose clamps.) There were no issues, and it never needed readjusting, but you can see it took a slight set, ostensibly loosing some of its spring strength over time.

Cheers, Bill

PS: Per the above linked installation instructions:

The dimensions provided in the "bellows compression chart" are average figures and are provided as a guide. The EXACT compression amounts required can vary due to different types of engine mounts and water pressure being fed to the seal. If you experience any spray or mist following the break-in period, make sure that the bellows have been compressed properly. If so, add 1/4" of compression to the seal, and soon the mist should disappear. Keep adjusting until the spray or mist stops.

[RSB333]

Thanks! I will be replacing ours at our next haul-out. It's been there as long as we've owned the boat: 7 years.
RSB333

[RSB333]

I'm replacing the dripless shaft seal over the winter with the boat on the hard. I can't get the shaft loose from the coupling. Next I'll try unbolting the coupling from the drivesaver. Teh engine is a Universal M-25. Any advice will be appreciated.
RSB333