1. Mechanical Seals
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754c Mechanical Seal (PS-754) – 1″
754c Mechanical Seal (PS-754) – 1″
Item #N/A
Single Spring Mechanical Seal 754c | PS-754 Equivalent
754c single spring mechanical seal, PS-754 / 754 equivalent. Fits 1″ shaft with 1.625″× 0.437″ cup seat and Type N-22 rotary head.
Key specs: Shaft size: 1.000″ single spring seal • Seat: 1.625″ x 0.437″ cup • Rotary OD: 1.547″• Working length: 1.625″
Crimped rotary head type N-22. Utilized in centrifugal pumps, mixers, rotating equipment, and further apparatus.
Interchange / replacements:
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Equivalent to Pac-Seal T-21 (long working length) and Burgmann MG9
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Can replace Type E and Type 1 in many applications (confirm dimensions)
Design & construction:
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Electro-polished 304 stainless steel metal parts
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Elastomeric bellows for stable sealing and easy installation
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Independent of shaft rotation
Material options (select above):
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CAR/CER/NIT — Carbon/Ceramic, Nitrile elastomers
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CAR/CER/VIT — Carbon/Ceramic, Viton elastomers
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SIC/SIC/VIT — Silicon Carbide/Silicon Carbide, Viton elastomers
Have questions? Check out our Single Spring Seal Guide or call us anytime—we’re here to help.
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 Gaskets.
Please click “specifications” below for OEM numbers and Pump Nameplate Data

758c Mechanical Seal (PS-758) – 1-1/2″
758c Mechanical Seal (PS-758) – 1-1/2″
Item #N/A
Single Spring Mechanical Seal 758C — 1-1/2″ | PS-758 Equivalent
758c single spring mechanical seal, PS-758 / 758 equivalent. Fits 1-1/2″ shaft with 2.125″×0.437″ cup seat and Type N-11 (Type C/21) rotary head.
Typical applications: Centrifugal pumps, mixers, and other rotating equipment.
Key specs: Shaft size: 1-1/2″ single spring seal • Seat: 2.125″ x 0.437″ cup • Rotary OD: 2.067″• Working length: 1.125″
Design & construction:
Crimped rotary head (Type N-11)—similar to industry Type C / 21; can also replace Type D / 2 with a simple spring change (in most cases). Electro-polished 304 stainless steel metal parts. Elastomeric bellows. Non-directional (independent of shaft rotation).
Materials available (choose from dropdown)
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CAR/CER/NIT — Carbon vs. Ceramic faces, Nitrile elastomers
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CAR/CER/VIT — Carbon vs. Ceramic faces, Viton elastomers
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SIC/SIC/VIT — Silicon Carbide vs. Silicon Carbide faces, Viton elastomers
Have questions? Check out our Single Spring Seal Guide or call us anytime—we’re here to help.
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 Gaskets.
Please click “specifications” below for OEM numbers and Pump Nameplate Data

7679c Mechanical Seal (PS-7679) – 1-3/4″
7679c Mechanical Seal (PS-7679) – 1-3/4″
7679c Mechanical Seal (PS-7679) – 1-3/4″
7679c single spring mechanical seal (also called 550CVSS), PS-7679 equivalent. Fits 1-3/4″ shaft with 2.500″×0.500″ seat and Type N-11 (Type C/21) rotary head; SiC/SiC with Viton (FKM).
Typical applications: Centrifugal pumps, mixers, and other rotating equipment.
Key specs
Shaft size: 1-3/4″ single spring seal • Seat: 2.500″ × 0.500″ cup • Rotary OD: 2.402″ • Working length: 1.375″Design & construction
Crimped rotary head (Type N-11)—similar to industry Type C / 21; can also replace Type D / 2 with a simple spring change (in most cases). Features an O-ring seat with rear relief slots for improved seating/fit. Electro-polished 304 stainless steel metal parts. Elastomeric bellows. Non-directional (independent of shaft rotation).Material: SIC/SIC/VIT — Silicon Carbide vs. Silicon Carbide faces, Viton elastomers
Cross reference & alternative part numbers
PS-7679
7679c
550CVSS (also searched as 550cvss / 550-CVSS / 550 CVSS)
PS-550
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 Gaskets.
Please click “specifications” below for OEM numbers and Pump Nameplate Data

844c Mechanical Seal (PS-844) – 2-1/8″
844c Mechanical Seal (PS-844) – 2-1/8″
Item #N/A
Single Spring Mechanical Seal 844C — 2-1/8″ | PS-844 Equivalent

851 Mechanical Seal (PS-851) —3/4″
851 Mechanical Seal (PS-851) —3/4″
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
Why choose 851 (PS-851):
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T-16 footprint for quick, drop-in replacement
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Machined carbon face for smoother sealing vs. molded carbon
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Dependable materials for standard pool/spa chemistry
Upgrades / Variations (same footprint)
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201c — Basic (Buna)
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3868 — Premium + Viton
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201cv — Molded carbon
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201cvss— Silicon Carbide / Silicon Carbide / Viton
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

957 Mechanical Seal (PS-957) — 5/8″
957 Mechanical Seal (PS-957) — 5/8″
Mechanical Seal 957 — Type 166 / T-16 (5/8″) | PS-957 Equivalent
Equal to industry standard 957 / PS-957.
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: 5/8″ shaft • 1.187″ × 0.343″ cup seat • Machined carbon/ceramic faces • Buna-N elastomers
Why choose 957 (PS-957):
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T-16 footprint for fast, drop-in replacement
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Machined carbon face for smoother sealing vs. molded carbon
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Dependable materials for standard pool/spa chemistry
Upgrades / Variations (same footprint):
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100c — Basic
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3866 — Premium + Viton
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100cv — Molded carbon
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100cvss — Silicon Carbide / Silicon Carbide / Viton
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

961 Mechanical Seal (PS-961) — 5/8″
961 Mechanical Seal (PS-961) — 5/8″
Mechanical Seal 961 — T-6A (5/8″) | PS-961 Equivalent
Equal to industry standard 961 / PS-961.
Direct-fit T-6A single-spring seal for pool/spa and small-pump applications—built with a machined carbon face for smoother sealing and longer life in everyday service.At-a-glance: 5/8″ shaft • 1.25″ × 0.406″ cup seat • Machined carbon/ceramic faces • Buna-N elastomers
Why choose 961 (PS-961)
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T-6A footprint for quick, drop-in replacement
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Machined carbon vs. molded carbon for improved surface finish and stability
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Dependable Buna-N for standard pool/spa chemistry
Upgrades / Variations (same footprint)
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1000 — Basic
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3865 — Premium + Viton
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1000cv— Molded carbon
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1000cvss — Silicon Carbide / Silicon Carbide / Viton
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 for OEM numbers and Nameplate Data

978c Mechanical Seal (PS-978) – 1-1/4″
978c Mechanical Seal (PS-978) – 1-1/4″
Item #N/A
Single Spring Mechanical Seal 978C — 1-1/4″ | PS-978 Equivalent
978c single spring mechanical seal, PS-978 / 978 equivalent. Fits 1-1/4″ shaft with 1.765″×.365″ seat and Type N-33 (tapered spring) rotary head.
Typical applications: Centrifugal pumps, mixers, and other rotating equipment.
Key specs: Shaft size: 1-1/4″ single spring seal • Seat: 1.765″ x 0.365″ • Rotary OD: 1.787″ • Working length: 1.062″
Design & construction:
Crimped rotary head (Type N-33)—equivalent to Pac-Seal T-21 (tapered spring) and Burgmann MG9, can replace seal type D & 2 type seal heads. Tapered spring for wide base to fit over impeller hub or other similar feature. Electro-polished 304 stainless steel metal parts. Elastomeric bellows. Non-directional (independent of shaft rotation).
Materials available (choose from dropdown)
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CAR/CER/NIT — Carbon vs. Ceramic faces, Nitrile elastomers
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CAR/CER/VIT — Carbon vs. Ceramic faces, Viton elastomers
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SIC/SIC/VIT — Silicon Carbide vs. Silicon Carbide faces, Viton elastomers
Have questions? Check out our Single Spring Seal Guide or call us anytime—we’re here to help.
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 Gaskets.
Please click “specifications” below for OEM numbers and Pump Nameplate Data

MG1 G4 Mechanical Seal – 25mm
MG1 G4 Mechanical Seal – 25mm
MG1 G4 Mechanical Seal (T-19) – 25mm
Direct-fit aftermarket MG1 G4 25mm mechanical seal replacement seal built for demanding pump applications where extended wear life and chemical resistance matter. This version uses a Viton elastomer with Silicon Carbide / Silicon Carbide (SiC/SiC) sealing faces, making it an excellent choice for tough water conditions, higher heat, and abrasive service compared to standard carbon/ceramic combinations.
Specifications
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Seal Style: MG1 G4
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Shaft Size: 25mm
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Seat Size: 38mm × 7.5mm
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Elastomer: Viton (FKM)
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Face Materials: Silicon Carbide / Silicon Carbide
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Cross Reference: T-19, HD-8038, STG4VSC25
Cross references & alternative part numbers
This seal is also commonly referenced as:-
T-19 25mm mechanical seal
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HD-8038 seal
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STG4VSC25 seal
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MG1 25mm Viton SiC/SiC seal
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25mm mechanical seal with 38 × 7.5mm seat
Need help confirming fit?
If you’re matching a seal by size, confirm the shaft size (25mm) and the seat (38 × 7.5mm) before ordering. If you want, send us the pump model and a photo of the old seal/seat for verification. -