851 Mechanical Seal (PS-851) — 3/4″ | Hayward Super Pump & Pentair IntelliFloXF Pool Pumps

ps-100 , ps-200 , ps-201 mechanical seal

851 Mechanical Seal (PS-851) — 3/4″ | Hayward Super Pump & Pentair IntelliFloXF Pool Pumps

Weight	.25 lbs
Dimensions	1.5 × 1.5 × 1.25 in

QTY	Price
851 Mechanical Seal (PS-851) — 3/4" \| Hayward Super Pump & Pentair IntelliFloXF Pool Pumps quantity	$7.00

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DESCRIPTION

Mechanical Seal 851 — Type 166 / T-16 (3/4″) | PS-851 Equivalent

Equal to industry standard 851 / PS-851.
Direct-fit Type 166 / T-16 single-spring seal for pool/spa and small-pump applications—built with a machined carbon/ceramic face set and Buna-N elastomers for reliable everyday service.

At-a-glance specs: 3/4″ shaft • 1.375″ × 0.406″ cup seat • Machined carbon/ceramic faces • Buna-N elastomers

Fits: Hayward Super Pump®, Super Pump II, Super Pump VS and the original Max-Flo (SPX1600Z2), Pentair IntelliFloXF® and SuperFlo® VST (17351-0101S), Sta-Rite Dura-Glas® II, Max-E-Glas™ II, Max-E-Pro® and Dyna-Pro®, plus Pac-Fab, American Products, Purex, Swimquip and Jacuzzi pool and spa pumps. The standard Pentair IntelliFlo takes the PS-1000; Pentair SuperFlo / SuperFlo VS and Hayward Max-Flo II take the PS-200.

Same seal, same size, same fit — what changes is the material and how it’s built. All five seals below are the PS-201 for a 3/4″ shaft, and all five fit the same pumps. They differ in two ways. The build: a molded carbon face or a premium carbon face machined from solid stock. The materials: a ceramic or silicon carbide seat, and Nitrile or Viton rubber. Pick the one that suits your water.

Seal	Material	Best For This Water
201c	Molded carbon face, ceramic seat, Nitrile rubber	Normal chlorine, normal temperature, clear water. The standard build for a home pool or spa.
201cv	Molded carbon face, ceramic seat, Viton rubber	Saltwater or higher chlorine, and warmer water. Viton holds up where standard Nitrile hardens and cracks.
851	Machined premium carbon face, ceramic seat, Nitrile rubber	Saltwater pools with a chlorine generator, commercial pools, or any pump that runs most of the day.
3868	Machined premium carbon face, ceramic seat, Viton rubber	High chlorine and hot water — heated spas, therapy pools, heavy commercial duty.
201cvss	Silicon carbide face and seat, Viton rubber	Sandy, dusty or gritty water, or any pump where seals keep failing early. The hardest faces we offer.

Rebuilding a Hayward Super Pump or Super II?Get this 851 seal in a complete kit with both gaskets — choose Premium – Machined Carbon/Ceramic/Nitrile (851) from the kit drop-down.

Doing the job yourself? Read How to Replace a Mechanical Pump Seal.

Please click “specifications” below for OEM numbers and Pump Nameplate Data

SPECIFICATIONS
Cross references & alternative part numbers

OEM number: 11107939 , 30220F , S20794, S21961 , W105-1 , 0000059 , S1190 , 296-5040-00 , SP1600Z3 , 170480001 , 2120-0010 , 48244 , 240260 , 3201625000 , 170480001 , 170480001, 37400-0027S , 32223, 322231H , 5P414, 1R299 , 70X107-M , 17-62372-008

Brands: ABS USA (SULZER) , ACE PUMP CORPORATION , BERKELEY PUMPS (A PENTAIR Brand) , CH&E MFG. COMPANY , CRANE PUMPS & SYSTEMS , HALE PRODUCTS, INC. , HAYWARD INDUSTRIES, INC. , HYDROMATIC. , PUMP COMPANY , HYPRO CORPORATION , MAGNUM PRODUCTS, LLC. , MONARCH PUMPS (Division of FRANKLIN ELECTRIC COMPANY, INC.) , MOYNO, INC. (A NOV Brand) , PENTAIR, INC. , STA-RITE INDUSTRIES , STONE CONSTRUCTION , TEEL PUMP , WEBER INDUSTRIES, INC. , WEIL PUMP COMPANY, INC. (Part of WILO USA)

Nameplate Data: ACH-150, 200, 300, 500 ACXH-150 , BCH-100, 200, 300 , 1P855-868-869-895,1P913, 1P950 2P007-008, 2P333, 3P525 3P526, 3P600

Also known as / searched as
- PS-851 mechanical seal
- 851 mechanical seal
- Type 166 mechanical seal 3/4
- T-16 mechanical seal 3/4
- pool pump mechanical seal 3/4
- spa pump mechanical seal 3/4
- Replacement style commonly used for Type 16, G, A, 6, AV, 2100 (verify size/fitment)
PHYSICAL PROPERTIES
Seal House Type 166
Our Type 166 configuration combines the best design elements we’ve refined over the years to deliver superior reliability and performance.

Key advantages include:
- Crimped rotary face with positive drive — securely held in place to prevent dislodgement during installation.
- Full metal retainer with positive drive — ensures strength and long-term durability.
- Full rubber bellows construction — provides complete sealing along both the shaft and face, rather than relying on a small O-ring or partial gasket.
- Molded/machined carbon face (never plastic) with upgrade options — delivers extended service life.
Compatibility & upgrade:

The Type 166 is designed to replace most small seal types commonly used in pool and spa applications, including Type 16, G, A, 6, AV, 2100, and more. Even in its basic form, this seal is a significant upgrade over standard “pool” seals typically available on the market.

Disclaimer: Seal House USA provides aftermarket replacement parts. Any OEM names are used strictly for cross-reference. We are an independent supplier.