3866 Mechanical Seal (PS-3866) — 5/8″ | Sta-Rite & Pentair Dura-Glas, Max-E-Glas Pool Pumps

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

3866 Mechanical Seal (PS-3866) — 5/8″ | Sta-Rite & Pentair Dura-Glas, Max-E-Glas Pool Pumps

Weight	.25 lbs
Dimensions	1.5 × 1.5 × 1.25 in

QTY	Price
3866 Mechanical Seal (PS-3866) — 5/8" \| Sta-Rite & Pentair Dura-Glas, Max-E-Glas Pool Pumps quantity	$9.00

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DESCRIPTION

Mechanical Seal 3866 — Type 166 / T-16 (5/8″) | PS-3866

Equal to industry standard 3866 / PS-3866.
Direct-fit Type 166 / T-16 single-spring seal for pool/spa and small-pump applications—upgraded with Viton elastomers and a machined carbon/ceramic face set for longer service life.

At-a-glance specs: 5/8″ shaft • 1.187″ × 0.343″ cup seat • Machined carbon/ceramic faces • Viton(FKM) elastomers

Same seal, same size, same fit — what changes is the material and how it’s built. All five seals below are the PS-100 for a 5/8″ 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
100c	Molded carbon face, ceramic seat, Nitrile rubber	Normal chlorine, normal temperature, clear water. The standard build for a home pool or spa.
100cv	Molded carbon face, ceramic seat, Viton rubber	Saltwater or higher chlorine, and warmer water. Viton holds up where standard Nitrile hardens and cracks.
957	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.
3866	Machined premium carbon face, ceramic seat, Viton rubber	High chlorine and hot water — heated spas, therapy pools, heavy commercial duty.
100cvss	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.

Explore our full lineup of Single Spring Seals—PS replacements, pool/spa seals, and our SPS line.

Looking for more? Shop Pump Repair Kits, Parts & Accessories, and Pre-Cut Gaskets.

Have questions? Check out our Pool/Spa Small Pump Guide or call us anytime—we’re here to help.

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

SPECIFICATIONS
Cross references & alternative part numbers

OEM numbers: 4547 , 17351-0102

Brands: Anthony & Sylvan Corporation , Pentair Pool Products

Nameplate Data: AJ Series , L-Series™

Also known as / searched as
- PS-3866 mechanical seal
- 3866 mechanical seal
- PS3866 seal / PS 3866 seal
- Type 166 mechanical seal 5/8
- T-16 mechanical seal
- pool pump mechanical seal 5/8
- spa pump mechanical seal 5/8
- machined carbon ceramic pump seal Viton / FKM
- Replacement style commonly referenced alongside 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.
- Quality materials — 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.

Weight	.35 lbs
Dimensions	2.25 × 2.25 × 1.75 in