SKU: 42074210986

PSS PRO Shaft Seal 2-3/4" Shaft 4" Tube

Sale price$488.16 Regular price$542.40
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Description

PSS PRO Shaft Seal 2-3/4" Shaft 4" TubePRO Shaft Seal 2 3 4" Shaft & 4" Tube The PSS PRO Shaft Seal is a mechanical face seal utilizing PSS Shaft Seal's proven stainless steel and carbon sealing components but adding reinforced silicone bellows, a secondary shaft retention collar, 316 stainless steel hose clamps (rolled edges and non perforated), and an optional Nitronic 50 rotor upgrade (for highly corrosive environments). Designed specifically for applications that will require increased

PRO Shaft Seal 2-3/4" Shaft & 4" Tube

The PSS PRO Shaft Seal is a mechanical face seal utilizing PSS Shaft Seal's proven stainless steel and carbon sealing components but adding reinforced silicone bellows, a secondary shaft retention collar, 316 stainless steel hose clamps (rolled edges and non-perforated), and an optional Nitronic 50 rotor upgrade (for highly corrosive environments). Designed specifically for applications that will require increased durability and resistance to harsh, corrosive, high-pressure, and otherwise demanding environments, the PSS PRO Shaft Seal is a specialized mechanical seal suitable for various applications with unmatched performance.

As with PSS Type A & B Seals, the PRO Shaft Seal is a mechanical face seal. The sealing surface is created between the flat surfaces of the rotating stainless-steel rotor and the stationary carbon flange. The stationary carbon flange is attached to a heavy-duty silicone bellows attached to the vessel’s stern tube (shaft log) with 316SS hose clamps. The stainless-steel rotor is fitted on the shaft in front of the carbon flange and is used to compress the bellows. The rotor is then secured to the shaft with set screws, and the shaft retention collar is installed. This compression (pre-load) maintains constant contact between the two mating faces of the stainless-steel rotor and carbon flange, allowing the PSS to compensate for the variable axial movement due to propeller thrust. In addition, the carbon flange is over-bored to the shaft diameter, allowing it to "float" around the shaft and thus compensate for most misalignment and vibration from the drive line. The stainless-steel rotor is sealed to the shaft by two O-rings recessed into the rotor's bore. These O-rings rotate with the shaft and the stainless-steel rotor and therefore do not experience wear during operation.

Components:

Shaft Retention Collar

The PYI Shaft Retention Collar is designed to help retain the propeller or rudder shaft in a vessel in the event of catastrophic failure of the coupling or if the shaft comes free from the coupling. The double-split design provides maximum axial holding power with quick and efficient assembly with the shaft installed. The design fully engages the shaft without marring. Easily installed where major disassembly would otherwise be required. Greater axial holding power than set screws or one-piece clamping collars. Effective on hard and soft shafts.

Rotor

The rotor on the PRO seal is manufactured out of 316L stainless steel and machined to a 9–12Ra finish on precision CNC lathes. It is secured on the shaft using 2 pairs of set screws positioned at a 90-degree angle; in addition, a locking collar is placed in front of the rotor and further retains the propeller or rudder shaft in case of catastrophic failure of the coupling or if the shaft comes free from the coupling. As on the Type A seal, the stainless steel rotor further polishes the carbon stator during the initial hours of operation.

Carbon Stator

The high-density resin-impregnated carbon stator is manufactured from an advanced composite that is first mixed, molded, and then formed under pressure. The blank parts are then baked, machined, and lapped to a measured flatness of 4 helium light bands (measured at 0.000044" of variation over its entire lapped surface). The grade of carbon composite used in the PSS Shaft Seal has a maximum operating temperature of 500 °F (+260 °C) and cannot melt if the seal runs dry for a short period, unlike a lip seal or a plastic face seal. In addition, the high density of the carbon greatly increases 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.

Bellows

The bellows on both the PRO and Type B PSS seals are constructed out of high-temperature silicone laminated with either 4 or 5 plies of polyester fabric (aramid in larger sizes) and covered with a layer of fluorosilicone. In addition, both ends of the bellows are sealed so no water can get into the polyester/Aramid fabric. The 4 or 5 fabric inlay provides excellent strength to abrasion and resistance to pressure without loading the silicone. On the larger models, the strength is greatly increased by using stainless steel hoops laid into the convolutions of the bellows.

Hose Barb

For high-speed vessels (planning hulls or vessels powering over 12 knots), it is required that a positive water supply be plumbed to the PSS Shaft Seal for lubricating and cooling the seal faces. There are many water supply sources; review the PSS Shaft Seal Installation Instructions for more information and note that all plumbing must follow the standards and practices of proper boat plumbing. In most cases, a slow-speed boat with no bearing in the shaft log does not require positive water feed and can be "vented." Ideally, the vent line will be run at least 2-3 feet above the waterline and as close to the centerline as possible to ensure the vent hose is never below the water line, even if the boat heels. Again, review the PSS Shaft Seal Installation Instructions for more details on venting the seal.

Specifications:

  • Temperature Limits: -13°F to 425°F (-25°C to 220°C)
  • Pressure Limits: 40 PSI (2.75 BAR)
  • Shaft RPM Limits: 10,000 RPM
  • Carbon Graphite: Lapped to 4 HLB (0.000044" tolerance)
  • 316SS / Nitronic 50: Faced to 9 Ra
  • Bellow Material: Molded formed silicone/fabric

Product Dimensions:

  • Shaft Diameter: 2-3/4"
  • Stern Tube Diameter: 4" to 4-1/8"
  • Uncompressed Length: 9.988"
  • Approx. Compressed Length: 8.988"
  • Rotor Diameter: 5"
  • Stern Cuff Length: 1.3"
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 42074210986

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John Grey
Fort Morgan, US
★★★★★ 5
As described
Color: Black
Light weight, easy to put together and you can disconnect the ends and just roll the whole thing nice and tight for quick out of the way storage. Pretty sturdy, doesn't fall over if you bump into it, you could use it outside but if there's a lot of light you can see through a tiny bit if you're really close but I only tested this indoors so not sure about patio types
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Reviewed in the United States on December 18, 2025
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Verified Purchase
Amyth4
Alexandria, US
★★★★★ 2
Flimsy - choose something else
Color: Black
Very flimsy and barely stands up… better options out there.
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Reviewed in the United States on October 11, 2025
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Lorraine
Dallas, US
★★★★★ 4
Smooth, Stable, and Perfect for Flexible Spaces
Size: 88''W-4 Panel, Color: Grey, Size: 88''W-4 Panel, Color: Grey
This room divider is incredibly easy to move thanks to its industrial-grade silent casters. It glides smoothly across different floor types with just one hand and without any noise, while the built-in wheel locks keep it firmly in place once positioned, no slipping or unwanted movement. The base with reinforced steel feet adds impressive stability, preventing wobbling even in busy or high-traffic areas. I also love the foldable design, which makes storage effortless when it’s not in use. It folds down compactly and fits neatly into small spaces. I gave only 4 stars because I'm not crazy about the color of the fabric. Otherwise this is a very functional way to separate areas.
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Reviewed in the United States on January 7, 2026
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K
Cuba, US
★★★★★ 5
easy to put together, stable and blocks out unwanted eyes.
Size: 88''W-4 Panel, Color: Grey
If you live in a high rise building, or where there is lots of foot traffic and can see in your windows, this is a must have. It's portable, can fold down one or two walls and easy to move around. Put together once, and block out light and eyes while tall enough to see over. You can fold it up along the wall, and use it to block out the blinds or light when using a projector so that it's darker. You can use it to partician the room if you share one, and separate your pile of junk from your room so you don't look at it, can take quite a bit of towel weight and clothes and doesn't tip over. Sturdy bottom metal and easy to put together. I got the grey one, and glad I did. I use it everyday and is part of my room decor. I love it, and after using it for a few months it's quite durable. The quality is there for sure. A tad pricey, but worth it. Must have for a private person.
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Reviewed in the United States on March 28, 2026
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KKat 10
West Palm Beach, US
★★★★★ 5
Well made dividers.
Size: 88''W-4 Panel, Color: Grey
Very durable and stable. Once positioned, they stay upright and firm and don't wobble around. Good materials on both the panels and the frame that supports it. Great for any partitioning needs and a fair price for the quality you receive. Highly recommended.
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