Pss Shaft Seal

[Magic1]

Own 2002 Catalina 400 with the "old" low speed PSS shaft seal. has worked flawlessly for 9 seasons. During a 10 day cruise last week on the Chesapeake Bay, discovered the PSS shaft seal leaked (badly) between the bellows and seal plate whenever RPM advanced above 3000 or "jam" throttled from idle to around 2600. Anyone else had this problem and if so, what did you do to correct?

Tim Leighton
S/V "Magic"
Chesapeake Bay

[deniseO30]

The bellows may have lost some of it's resilience, you may want to replace that or possibly just move the collar back more. Also, make sure you "burp" it and make sure there isn't anything like algae between the surfaces. I think "whip" in the shaft would make it leak also. Hope this helps. I have one my boat. love it!

[T37Chef]

The bellows would be my guess. You may want to throw on a shaft clamp while your at it if you don't already have one, see here: McMaster-Carr

BTW, whens the last time you checked your alignment?

[jrd22]

Can't remember what the recommended replacement time is for the bellows, but I'm guessing it's less than 9 years.

[Gene T]

I agree with Denise that you should retention the collar. There is a set amount of compression (movement of the collar) that depends on shaft size. The people at PYI could probably tell you how much it is.

I think the recommended replacement is 10 years (that may be the non official recommendation).

If your engine alignment is off that could cause severe movement at the seal too, so I would check alignment.

I would also make sure your prop isn't bent or that you have some line wrapped around it causing the vibration.

Gene

[T37Chef]

for some reason I recall it being 7 years, surely a inquiry will help you...PSS Shaft Seal: The world’s leading dripless seal.

[Maine Sail]

Originally Posted by Magic1

Own 2002 Catalina 400 with the "old" low speed PSS shaft seal. has worked flawlessly for 9 seasons. During a 10 day cruise last week on the Chesapeake Bay, discovered the PSS shaft seal leaked (badly) between the bellows and seal plate whenever RPM advanced above 3000 or "jam" throttled from idle to around 2600. Anyone else had this problem and if so, what did you do to correct?

Tim Leighton
S/V "Magic"
Chesapeake Bay

Your motor mounts are likely getting worn and allowing the motor to move forward under load OR the stainless rotor has moved or become loose. If you have a 2002 boat the bellows is due anyway so might as well upgrade to the vented PSS. They will sell you a new bellows and the vented carbon disk for quite a reasonable cost.


In the meantime:

1- Mark the shaft where the stainless rotor is now using a sharpie marker or electrical tape.

2- Remove the set screws on the stainless rotor, there should be TWO in each hole and compress the bellows with the stainless rotor perhaps another 1/4" beyond where it is now. Run up to full WOT RPM and make sure it is not leaking. If it is and shaft is true etc. then move it back another 1/8" to 3/16" and try again.

Two Set Screws:


3- Install NEW set screws. PYI will ship them to you. DO NOT re-use the old screws!

1 Use vs. New:



This should solve your problem but you may want to investigate your motor mounts.

Oh and as added safety measure to prevent the stainless rotor from moving have PYI send you one of their new "clamp collars" as well.

[JiffyLube]

What is the purpose of the vent?

[Maine Sail]

Originally Posted by JiffyLube

What is the purpose of the vent?

To keep lube water inside the seal and prevent it from becoming an air trap, over heating and squealing. On many boats a quick thrust of reverse will send air bubbles up onto the shaft log which have no way to get back out. Also sailing in rough weather can create trapped air up inside the shaft log. Some boats are worse in this regard than others. My old C-36 needed to be burped about every three week to get the air out, a royal PITA..

[olson34]

I spoke to a PSC rep at a show several years ago about the dropping of the original non-vent seal and also the life expectancy of the bellows.

He said that there was always some chance that someone would buy the non-vent version (for boats motoring under 12 kts) and somehow thru misuse or resale it would wind up on a too-fast boat. Easier to just consolidate to one model, altho not necessary on our sailboat.

Ten years is about right to replace the bellows, altho they can normally go years longer. So if we have a haulout scheduled near that time interval, just replace it then.
"Not for attribution, but this bellows replacement time was specified by the liability lawyers and not the engineers." (or words to that effect.)

We had a PSS seal installed in about '95, and never had a bit of trouble. After talking with the rep, replaced the bellows at a haulout for a bottom job about a decade later.

A dry bilge is nice.