Tides Shaft Seal Replacement

[a_braley]

My PT40 #56 (2003) is on the hard waiting to be unwrapped and launched for the season once it warms a bit in Valdez, AK. The vessel still has the original Tides shaft seal which was installed during the build 22 years ago. I contacted Tides Marine about when the seal should be replaced and the answer was of course now. Since the boat is new to me I don't know the history but the silicon sleeve of the seal looks fine and there is a replacement lip seal mounted on the shaft.

The replacement assembly is about $700 so I am planning on going ahead and replacing it before launch next month just to be safe. I am wondering if anyone knows the stern tube OD for the PT40? My boat is 365 miles away and I would like to have the new seal in hand before driving down later this month. Tides lists stern tube sizes in 1/8" increments.

thanks ALAN

 

[Mac2]

Why aren’t you just replacing the lip seal?

 

[a_braley]

I asked TIDES and they said to replace the seal including the articulated hose. Your question is valid. I wonder how many 20+ year TIDE shaft seals there are out there that never had the silicon hose replaced, just the lip seal.

 

[Mac2]

I asked TIDES and they said to replace the seal including the articulated hose. Your question is valid. I wonder how many 20+ year TIDE shaft seals there are out there that never had the silicon hose replaced, just the lip seal.

Did they give you a timeframe to replace the silicone hose?

 

[a_braley]

No they did not give ne a recommended replacement interval for the articulated hose. Tidemarine did say the shelf life of the lip seal is 7 years.
PSS says on their site that the bellows for their A seal (nitrile/pvc) should be replaced every 6 years and the bellows on their PRO (silicone) should be replaced every 10 years.
I will give Tides a call on Monday and see if they will sell me just the silicone tube and lip seal.
I am not a materials engineer but I can’t understand why the articulated silicone tube would degrade to failure when it is only under a foot or two of head.
That said, out an abundance of caution I will replace it while I have the shaft loose to install the lip seal.

Will let you know what Tide says after I talk to them

 

[Mac2]

Appreciate that. I’m sure it all depends on the environment the silicon is in. $700 seems a little ridiculous, but nothing compared to peace of mind

 

[luna]

The 9" long rubber hose that at one end slides over my fibreglass stern tube and at the other end fits over the Norscot bronze lip seal carrier is now approaching 30 years old and still functions just fine.

If you think about it, the goal when you align things is to have everything (shaft, coupler gear flange) on the same centerline. Once you achieve this there really is no load on the hose, as even when the engine moves slightly forward due to the flexible mounts, the movement is almost on the same centreline and the shaft simply slides in the lip seals.
Rubber stuff lasts a long time if they are not worked. If your lip seals are indeed 22 years old and do not leak, I think things are likely aligned pretty well.

That being said, the lip seals themselves are likely nothing special and if so, I would think can be obtained from a seal vendor for a lot less than what the Tides people charge.
With the shaft log hose you need to be a little more careful, as I think there is hose that is produced especially for shaft logs without any coil set in it. For this application you need hose that is straight, not curved from being coiled.

At 22 years old on a new to me boat, I would likely change both the lip seals and the stern tube (shaft log) hose.

Norscot Shaft Seals 40240 | Fisheries Supply

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[Mac2]

This is the Tides Marine shaft seal. There are two spare lip seals on the shaft. One silicone hose is for cooling the seal and the other is a crossover going to the other shaft seal (I added the flow meter to the cooling water). The OP is referencing the blue articulated silicone hose around the shaft. Could that be $700?

 

[luna]

I have no idea as to what size is required by the OP but it would be a stretch to find the hose itself, at any reasonable size to fit a 40' boat, to be worth $700.

Shaft Seals - Tides Marine

Kawartha Propeller specializes in propeller, lower unit, shaft, impeller, strut, and rudder repairs and sales. We also sell Tides and PSS shaft seals, Morse bearings, prop pullers, hub kits, and all propeller hardware.

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