PSS PRO Shaft Seal - 2-1/2" Shaft Dia, 4" to 4-1/8" Stern Tube Dia

The PSS PRO Shaft Seal is a mechanical face seal utilizing PSS's proven stainless steel and carbon sealing components, while adding a reinforced silicone bellow.
The seal comes with external reinforcing SS rings on the bellow on sizes 2-1/4" and up (optional on all smaller sizes), a shaft retention collar, 316 stainless steel hose clamps (solid band with rolled edges). An optional Nitronic 50 SS alloy rotor upgrade (for highly corrosive environments) is available.

The PRO Shaft Seal is designed specifically for applications that will require increased durability and resistance to harsh, corrosive, high pressure and otherwise demanding environments. It is a specialized mechanical seal that is suitable for a variety of 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 stator flange. The stationary carbon flange is attached to a heavy duty silicone bellow which is 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 bellow. 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.

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 that are recessed into the bore of the rotor. These O-rings rotate with the shaft and the stainless-steel rotor, and therefore do not experience wear during operation.

• Two nitrile O-rings seal the stainless steel rotor to the shaft and will not experience wear
A primary set screw and a backup set screw (2 sets) are used to secure the stainless steel rotor to the shaft
A seal is created between the two mating faces of the carbon stator and the stainless steel rotor
Raw water is fed to the PSS Shaft Seal for cooling / lubricating the seal faces on high speed vessels

All shaft seals include a hose barb fitting on the carbon flange for either simple venting to air above the waterline (to let any trapped air escape the seal on low speed boats), or for a cooling water feed (on vessels over 12 knots) which is easily installed with the use of a Water Pick-Up Hose Tee Kit, sold separately. High speeds can create a vacuum in the seal, starving it of lubricating water.
On twin engine installations, the cooling water plumbing must be linked between engines in case one engine is shut down while the other continues to power the boat in excess of 12 knots - this ensures both seals remain lubricated. See Installation Instructions.

PSS shaft seal standards –
• 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 Stator: Lapped to 4 HLB (0.000044" tolerance)
• 316 (std)/Nitronic 50 (opt) stainless steel Rotor: Faced to 9 Ra
• Bellow Material: molded, formed silicone/fabric