PSS Shaft Seal - For 65 to 95mm Shafts


$ 837.00 USD

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Size Guide
  • Description

    The PSS Shaft Seal is the #1 selling marine mechanical seal worldwide and is installed as standard equipment by many of the worlds most reputable boat builders and boat yards. The PSS Shaft Seal is also recognized as the premiere retrofit (aftermarket) seal on the world market. Boat builders and boat yards recognize the advantages and value of installing the PSS as it eliminates the maintenance, constant adjustment & cost associated with traditional packing type glands. Aside from these benefits, the PSS Shaft Seal helps to eliminate water in the bilge (100% water tight) & wear to the propeller shaft.

    1. ABS Certified
    2. RINA Certified
    3. Bureau Veritas Certified
  • Documents
    1. PSS Type A & PRO Shaft Seal Installation Instructions
    2. PSS Type B Shaft Seal Installation Instructions
    3. PSS Shaft Seal Warranty
PSS Type A Shaft Seal

How Does It WOrk?

1. Two nitrile o-rings seal the stainless steel rotor to the shaft and will not experience wear.

2. A primary set screw and a backup set screw (2 sets) are used to secure the stainless steel rotor to the shaft.

3. A seal is created between the two flat surfaces of the carbon stator and the stainless steel rotor.

4. Water is fed into the PSS Shaft Seal for cooling/lubricating the seal faces on high speed vessels.

5. The stationary carbon stator is attached to the nitrile bellow, which is attached to the stern tube (shaft log).

Stainless steel rotor for a PSS PRO Shaft Seal


The PSS stainless steel rotor is slid down the shaft and is secured to the shaft with set screws at 90° for maximum holding power. Precision tolerances are maintained by computer controlled lathes. The faces have a number 9 micro finish and are perpendicular to the bore to prevent run-out as the collar rotates. The carbon graphite stator will polish the face of the rotor during the first few minutes of operation. The stainless steel rotor should not need to be replaced under normal operating conditions. The stainless steel rotor used on the PSS Type A Shaft Seal is made from 316L stainless steel.

Carbon Stator for a PSS PRO Shaft Seal

Carbon Stator

The high density, resin impregnated carbon/graphite stator is a composite that is first mixed, molded and then formed under pressure. The blanks are then baked, machined and lapped. The face of our carbon is finished to a flatness of 4 helium light bands (measured .000044" of variation over entire lapped surface). The grade of carbon used in the PSS has an operating temperature over 500° Fahrenheit (+260° Celsius), and cannot melt if the seal runs dry, unlike a rubber lip seal or plastic face seal. The high density of the carbon greatly increases the longevity and wear resistance. Several commercial vessels have recorded over 40,000 (over 4-1/2 years of continuous operation) engine hours on the same, original components. The carbon should not need to be replaced under normal operating conditions.

Rubber bellow for PSS Shaft Seal


The PSS Type A Shaft Seal bellow is made from rubber (Nitrile), and has a temperature rating of -25°F to +225°F (-31°C to +107°C). Nitrile is known for its resistance to weathering. Nitrile rubber is exceptionally resistant to oils and non-polar solvents. It also offers good gas impermeability, abrasion resistance, and better thermal stability than most general purpose elastomers.

Installation Video

Customer Reviews

Based on 55 reviews
As Advertised.

As far as the seal system goes, easy installation process. Installed on 1-1/2” shafts. The new seal appears to be twice as thick-walled as the ones that they replaced which were estimated to be at least 16 years old if not older. Held back the water on initial launch, not so much as a drop. Burned in new stators in under an hour. Hardly noticeable dusting/spraying during break in period, just a faint black line in the bilge letting me know all had seated/burned in properly.

The team has fielded calls from me in the past. Very knowledgeable, pleasant, and helpful.

David A Snyder
Great service, great product

After 17 years of use without any issues out of prudence we replaced a PSS Shaft Seal on our sailboat. The product speaks for itself and the service (thank you Erik) was amazing.

Nathan Brown
Absolutely top notch products

The PYI team is the best! You get what you pay for and everything they offer is a true value for your boat. Highly recommended

R Duncan OQuinn
Great service and product.

PYI always has what we need and ships out quickly.

Charles Mitchell

PSS Shaft Seal - For 20 to 60mm Shafts