Dripless Shaft Seal Replacement Question

[Fiftybucks]

Can this be replaced with the boat in the water?
looks pretty corroded..... all new or use 'service kit?
does the propeller shaft have to move back to insert the new seal?
looking for some advice on how to approach from experienced person.

Dripless Shaft Seal

[Sailmonkey]

Is it possible? Yes.....but since your asking, no. The best course of action will be to pull the boat to pull the shaft and replace this.

As an aside, I’m not sure there’s enough room there for the pss shaft seal in the first place. In order to provide the correct compression it appears as though your rotor would need to be at least up against the coupling.

Personally, I’d replace the PSS with a Volvo seal (I have a PSS, but don’t think it’s suited to your boat).

[wingless]

The dripless seal should be maintained to specifications, including periodic verification of supply flow while engine is operating and verification of seawater back flow when hose disconnected.

That fitting corrosion does not look good and is concerning for a silent failure.

[chouliha]

Originally Posted by Sailmonkey

Is it possible? Yes.....but since your asking, no. The best course of action will be to pull the boat to pull the shaft and replace this.

As an aside, I’m not sure there’s enough room there for the pss shaft seal in the first place. In order to provide the correct compression it appears as though your rotor would need to be at least up against the coupling.

Personally, I’d replace the PSS with a Volvo seal (I have a PSS, but don’t think it’s suited to your boat).

I agree I do not think there is enough room on the shaft to put the PSS seal on correctly. Hence why it’s overly compressed

[Sailmonkey]

Here’s a link to a seal better suited to your boat.

https://www.generalpropeller.com/381...SABEgK86vD_BwE

[Twilite]

Never ceases to amaze me how absolutely insane Volvos parts pricing is.

[Sailmonkey]

Originally Posted by Twilite

Never ceases to amaze me how absolutely insane Volvos parts pricing is.

It’s 1/3rd the price of the PSS seal!

[Pizzazz]

The recommended way to replace the PSS is to pull the shaft inwards, below the engine, so that you do not have to remove the gearbox coupling. No matter what you do, you cannot mount the coupling on the shaft accurately in place, it is best if the coupling is attached in a shop where they can make sure it is straight. This means that the only way it will go in the boat is from the inside out.

Given the above it is quite straightforward to do it in the water with a diver helping you out, assuming you have lifted the engine enough to have room. Then you plug the hole from the outside, attach the seal and put in the shaft. Some water will get in but usually it is small amount. Make sure your bilge pumps are working well. Can you sink the boat? Yes, if the shaft gets stuck. Is it likely? No. Is it easier than replacing a transducer in the water? Yes, much easier but it does look scary at first. Good luck.

[noelex 77]

The immediate problem of the “dry rotted and weeping” raw water hose supplying the PSS should be quite easy to replace with the boat in the water.

When the old hose is removed water will enter, but providing a correct sized replacement hose is at hand the water ingress will be minimal. if the hose is long enough to extend above the waterline the water will not rise above this level. Have plenty of rags, fresh water and dewatering spray (such as WD40) to immediately clean any engine parts sprayed with salt water.

However the PSS seal looks old and tired. I think it has been over compressed, probably to compensate for the bellows loosing compression with age. It is time for replacement. This is best done at the next hall-out. Replacement of the whole PSS seal in the water is possible in some boats, but it is not for feint of heart. Consider the hose replacement as temporary stop gap measure until the seal, or at least the bellows and “o” rings can be replaced.

PSS have a new “pro” seal with a longer lasting bellows that is worth considering. The “pro” bellows fit the original seal.

[Fiftybucks]

Is there any Negative to going to the old standby Packing Gland Nut system?

[a64pilot]

Originally Posted by Fiftybucks

Is there any Negative to going to the old standby Packing Gland Nut system?

You don’t have the latest greatest thing, and it may leak a little.
The Teflon or whatever packing I have never really leaks, it there is a wet ring around the shaft when I’m motoring

[rbk]

Higher chance of crevice corrosion on your shaft.

[stormalong]

That bellows is definitely over compressed. It looks like there is some room between the PSS and the coupling so it does not need to be as compressed as it is. If you need still more room could you get by without the high speed option - the water tap in the carbon ring?

But looking at the overall condition of the PSS it looks like it may be leaking. The SS ring may need to be refurbished - put on a lathe and faced, then polished. I had this done to my PSS about ten years ago and it helps reduce wear.

As for replacing it while in the water this is not for the faint of heart. Too many things can go wrong and it is highly dependent on there being room in the shaft log to temporarily pack it with rags from the outside and clearance room to extract the shaft far enough. If not enough clearance you will have to remove the transmission. Either way it is a risky business in the water.

[Fiftybucks]

As a PSS shaft seal wears, Do the bellows Shorten or Elongate? In other words is it just and indicator that it is completely worn out thus the compressed condition?

[noelex 77]

The bellows do not change their length with age, but they do lose their elasticity or “springiness”. This reduces the pressure between the black carbon face and the stainless steel rotor and the seal will start to leak a little. This takes some time, around 10-15 years is typical. At this stage the seal should be replaced (in fact PSS recommend periodic replacement before this stage is reached).

To temporarily fix the lack of springiness in the bellows caused by age, the stainless rotor can be moved backwards increasing the compression to the bellows and temporarily fixing the slight leaking. From the photo this looks to have been done to your seal. This together with the poor visual condition indicates it is time for replacement.