Advice requested: PSS bellows loose and leaking

[mattkab]

We came down to our fairly-new-to-us 4788, and noticed water coming out of one of the through hulls periodically.

After investigation, we found that the port engine PSS seal was leaking substantially where the stainless collar meets the bellows. We re-sat the collar, and stopped the leak, but the whole bellows is loose and can be wiggled. You can see how easy it is to move in the video. The starboard side doesn't move at all.

I'm just starting to investigate the fix, but open to suggestions and pointers.

 

[Tuttouomo]

Matt, the stainless collar should be tight on the shaft , and in a position to apply pressure to the bellows. There are allen set screws in the s/s collar and they should be tight and doubled up. The bellows should have approx. 1" of compression, but check with PSS as that dimension is variable with shaft diameter.

Bill

 

[mattkab]

Thanks.

Per the PSS compression chart, it should be 1". But 1" from what baseline, on a previous installation?

To "fix" the leak, we just pushed the stainless collar down the shaft about 1/4" -- sounds like maybe that's not enough?

 

[Tuttouomo]

The 1" is from the baseline of a fully relaxed bellow. If it still drips at 1", compress in 1/8 " increments.

Bill

 

[mattkab]

Thank you... that helps a lot, and that's pretty much what we did. Just compressed the collar until the leaking stopped.

Should I not be concerned with the "wiggle" in the bellows, if the leaking has stopped?

 

[Comodave]

As the bellows age, they loose some strength so they don’t apply as much tension on the seal. As suggested tighten it up and see how it goes. The bellows have a life span so depending how old it is it may need repalcement. Congrats on your new 4788.

 

[sunchaser]

Matt, the stainless collar should be tight on the shaft , and in a position to apply pressure to the bellows. There are allen set screws in the s/s collar and they should be tight and doubled up. The bellows should have approx. 1" of compression, but check with PSS as that dimension is variable with shaft diameter.

Bill

Three things I would suggest:

• Get new set screws for the SS collar from PSS, not knockoffs. Install them per the PSS protocol
• Put a suitably sized shaft zinc in front of the SS collar so it can't slip again.
• How old is the PSS system? If older than 8 years, at the next haul out replace the entire assembly, especially since it is a new to you vessel.

 

[mattkab]

Three things I would suggest:

• Get new set screws for the SS collar from PSS, not knockoffs. Install them per the PSS protocol
• Put a suitably sized shaft zinc in front of the SS collar so it can't slip again.
• How old is the PSS system? If older than 8 years, at the next haul out replace the entire assembly, especially since it is a new to you vessel.

Thank you...

1. I'll order new set screws today and have them shipped out
2. The zinc is a good idea, I'll order that too
3. I don't know how old the system is. Boat is a 2002, so it could be 15 years old. I'll dig through the paperwork on the boat to see if I can find something, but honestly I'd be surprised. Probably just change both out in the spring, in my scheduled haulout.

 

[porman]

The suggested replacement interval is 6 years. Our Mainship is now 15 years old and I'm sure they have never been replaced. Will take care of it at the next haulout.

 

[FlyWright]

I believe that the set screws are "stacked" so you must remove the first set screw to reach the 'working' set screw. Once it is tightened, the second set screw gets stacked into the same threads.

No doubt the PSS instructions cover this and this is probably what Sunchaser was referring to but thought I'd add that to the conversation....just in case it's overlooked.

 

[joekerins]

Had to replace mine last year, same issue, mine were in their 8th year.

I tried new screws after compressing a further 1/2", didn't work.

Once you set the collar, make a line with sharpie 1/2" forward of collar on shaft. This can be used to confirm collar is not moving forward after your first few runs.

 

[Ken E.]

I have these on both my drive shafts and rudder posts, and just had the maintenance procedure done a month ago while I was hauled out. The yard told me the bellows replacement interval was 5 years. The PSS website says every 6 years, which I looked up after the fact. So......I was had by a year.

 

[diver dave]

And, make sure the shaft did not move/slide into the coupler. Another set of set screws to mess with.

 

[Bigsfish]

I’m having a similar problem, after adjusting three time I decided to replace both assembles in their entirety. About four years of use but I don’t like taking chances on this type of keeping the boat afloat device. My previous boat went over ten years without an adjustment.

Al is correct, there are two set screws for each hole.

 

[aboatman]

My advice: Take it to a respected boatyard that's experienced with PSS seals. A screw up could be costly.

 

[RT Firefly]

Greetings,
Mr. a. " A screw up could be costly." Or in Mr. m's case, possibly, an un-screwup could be costly.

 

[mahal]

I plan to replace mine at the next haul out since I don't know its age. But wouldn't it be better to replace it with the traditional (bulletproof) stuffing box? Before Gore GFO, I would not consider this switch, but I'm not so sure now. I used Gore GFO packing on my previous boat and when I repacked it after 8 years, it still looked very good and gave me no problems all those years.

I just don't get the same peace of mind with my PSS system that I did with a brass stuffing box. The one drawback I can see is cost. The old style stuffing box with nipple for cooling water cost much more than a PSS kit.

Thoughts?

 

[RT Firefly]

Greetings,
Mr. m. I am of the same opinion as yourself. "bulletproof" and "peace of mind". Personally I do NOT like PSS or similar style systems. They are "solutions" looking for a virtually non-existent problem IMO. I would much rather tolerate a bit of water in the bilge than trust a system that might cause a sinking. A "classic" stuffing box system can be readily re-packed while in the water and $$-wise, a few feet of GFO packing is far less expensive than hauling and replacing a complete "dripless" system every 5-8 years.

 

[FF]

IF the bellows seal was done after the boat was built , the stock shaft seal setup may still be intact.

If it is you can toss the dangerous bellows and return to the origional style stuffing box, just be sure to install a modern packing like Duramax or similar.

The ceramic seal folks now use a heavy hose instead of the thin bellows , perhaps they offer a retrofit set up?

 

[aboatman]

Since when is a dripless seal "dangerous"? Thousands of boats are using them including mine.

 

[Pgitug]

If your PSS still leaks after the 1” Compression there may be “Gunk” where the seal disk meets the stainless flange. Take 400 grit sand paper doubled up and “Drag” it around the seal surface a few times to clean them.

 

[RT Firefly]

5 year old article:

https://www.passagemaker.com/technical/dripless-shaft-seals

 

[sunchaser]

5 year old article:

https://www.passagemaker.com/technical/dripless-shaft-seals

As this quoted article summarizes (read until end) a properly installed and maintained drip less system works as advertised and just as well as a non dripless system assuming of course recommended maintenance. Seems like the OP is interested in doing it right and should have no problems.

Like anything on a boat, let things go or do something wrong and problems arise. The classic but sad first hand case I'm aware of is during an insurance survey of a Feadship the insurer's hired gun turned and repositioned a set of valves he shouldn't have. The valve left open was an oil drain from a crankcase. Yes, the engine oil was dumped into the on board used oil tank, but the engine was running and soon out of oil. Insurer paid dearly for a new engine.

Or how about failed raw water hoses, bad through hulls or horror of horrors a ripped off IPS! Not to forget there are hundreds of thousands of bellows in use holding out the waters we race around in - millions actually on 60 years of stern drives.

 

[Tom.B]

5 year old article:

https://www.passagemaker.com/technical/dripless-shaft-seals

Oh great... something ELSE to now be worried about! I guess I need to check my PSS seals this weekend.

 

[RT Firefly]

Greetings,
From post #18. "Personally I do NOT like PSS or similar style systems." Not getting into a p*ssing contest. This is MY opinion. If you've got one of these or are thinking on getting one of these, fill your boots.

 

[sunchaser]

Greetings,
From post #18. "Personally I do NOT like PSS or similar style systems." Not getting into a p*ssing contest. This is MY opinion. If you've got one of these or are thinking on getting one of these, fill your boots.

RT, Thanks for posting an article that says PSS systems are just fine if installed and maintained properly. But you've never been shy about stating your opinions so hammer away, it is the Internet.

 

[mahal]

The price of a traditional water-cooled stuffing box is 4 times more than the ones without a water connection. How important is it for an 8 knot boat's shaft seal to be water cooled? Anyone here using Gore GFO packing without cooling water? The savings will be less than a boat buck, but if I can avoid paying for something that I don't need and simplify the set-up even more (less parts to fail), I'm all for it.

My reason for wanting to do the switch from PSS to traditional stuffing box is mainly for my own peace of mind. I do my best to be diligent with my systems check, but the stuffing box is something that I tend to not pay close attention to. Worse case scenario on a neglected traditional stuffing box is more acceptable to me than on a PSS. If the PSS seals were new, I don't think I would consider changing them, but since they are due for replacement ....

 

[twistedtree]

Have you considered a Tides Marine dripless seal. They have a different design approach compared to PSS. I have had both, and did need to do some adjusting on one PSS, but that was because the yard never secured the set screws, so not PSS's fault.

Any other experience with Tides?

 

[drb1025]

Replaced mine last week. 8 years old and still working well. Preventative maintenance. You can see the sharpie mark on the shaft from where it was compressed, per the installation instructions .

 

[sunchaser]

Replaced mine last week. 8 years old and still working well. Preventative maintenance. You can see the sharpie mark on the shaft from where it was compressed, per the installation instructions .View attachment 73724

What a great looking setup. DeFever does the PSS system correctly. But, good access and being openly visible helps. If I had a vessel with a "buried" shaft through hull that was not easily visible PSS would not be the ticket. Likely though that would not be a vessel we'd consider, or if we did borrow RT's Juneau Sneakers.