John Crane Type 1 O-Ring Pusher Mechanical Seals Replacement
MIAOYU offers direct replacement John crane type 1 mechanical seals for general service pumps. This standard single-spring design provides reliable sealing for water, oils, and mildly corrosive fluids. Pusher mechanical seals are available in a wide range of shaft sizes with various face material options (SiC, TC, Carbon) to match OEM dimensions and performance, ensuring easy installation and cost-effective maintenance.
Key Features
• Type 1 with O-Ring: A variation of the classic Type 1 that utilizes an O-ring secondary seal instead of the traditional elastomer bellow.
• High Pressure: The O-ring design is more robust against high pressure spikes than a rubber bellow.
• Universal Fit: Retains the standard Type 1 drive mechanism and dimensions for easy retrofitting.
• Robust Drive: The large single coil spring grips the shaft for positive drive, but the sealing is handled by a precision O-ring, offering a hybrid of robustness and high-pressure capability.
• Non-Clogging: The large spring resists fouling.
Technical Specs | Materials | ||
Mediums | Water, oil and weakly-corrosive mediums | Stationary Ring | Ceramic/Sic/TC |
Pressure | ≤1.4MPa | Rotary Ring | Carbon/Sic/TC |
Temperature | -20C to 120C | Secondary Seal | NBR/EPDM/Viton |
Speed | ≤15m/s | Spring and Metal Part | Stainless Steel |


Product Specifications
| D1 (inch) | Size Code | D1 (mm) | Size Code | D3 | D7 | L1 | L4 |
| 0.500 | 0127 | 12 | 0120 | 23.80 | 25.40 | 30.16 | 7.93 |
| 14 | 0140 | 27.76 | 31.75 | 33.32 | 10.30 | ||
| 0.625 | 0158 | 16 | 0160 | 27.76 | 31.75 | 33.32 | 10.30 |
| 0.750 | 0191 | 18 | 0180 | 30.94 | 34.93 | 33.32 | 10.30 |
| 20 | 0200 | 34.11 | 38.10 | 34.93 | 10.30 | ||
| 0.875 | 0222 | 22 | 0220 | 34.11 | 38.10 | 34.93 | 10.30 |
| 24 | 0240 | 38.10 | 41.28 | 39.67 | 11.10 | ||
| 1.000 | 0254 | 25 | 0250 | 38.10 | 41.28 | 39.67 | 11.10 |
| 1.125 | 0286 | 28 | 0280 | 41.28 | 44.44 | 41.28 | 11.10 |
| 30 | 0300 | 46.02 | 47.63 | 41.28 | 11.10 | ||
| 1.250 | 0317 | 32 | 0320 | 46.02 | 47.63 | 41.28 | 11.10 |
| 33 | 0330 | 48.68 | 50.80 | 42.85 | 11.10 | ||
| 1.375 | 0349 | 35 | 0350 | 48.68 | 50.80 | 42.85 | 11.10 |
| 1.500 | 0381 | 38 | 0380 | 51.85 | 53.98 | 42.85 | 11.10 |
| 1.625 | 0412 | 40 | 0400 | 58.10 | 60.38 | 50.80 | 12.70 |
| 43 | 0430 | 61.27 | 63.50 | 50.80 | 12.70 | ||
| 1.750 | 0444 | 45 | 0450 | 61.27 | 63.50 | 50.80 | 12.70 |
| 1.875 | 0476 | 48 | 0480 | 64.44 | 66.68 | 53.98 | 12.70 |
| 2.000 | 0508 | 50 | 0500 | 67.21 | 69.85 | 53.98 | 12.70 |
| 2.125 | 0539 | 53 | 0530 | 72.02 | 76.20 | 60.33 | 14.28 |
| 2.250 | 0571 | 55 | 0550 | 75.30 | 79.38 | 60.33 | 14.28 |
| 2.375 | 0603 | 60 | 0600 | 78.30 | 82.55 | 63.50 | 14.28 |
| 2.500 | 0635 | 63 | 0630 | 81.54 | 85.73 | 63.50 | 14.28 |
| 2.625 | 0666 | 65 | 0650 | 86.22 | 85.73 | 69.85 | 15.90 |
| 2.750 | 0698 | 70 | 0700 | 89.40 | 88.90 | 73.03 | 15.90 |
| 2.875 | 0730 | 73 | 0730 | 92.57 | 95.25 | 73.03 | 15.90 |
| 3.000 | 0762 | 75 | 0750 | 95.75 | 98.43 | 73.03 | 15.90 |
Workshop
This workshop is equipped with professional processing equipment and integrated with standardized material warehousing management, enabling a one-stop production process from precision machining to finished product delivery. It ensures part machining accuracy and production efficiency, meeting various high-specification manufacturing requirements.




Product Research, Development and Testing
Our Product R&D and Testing focuses on optimizing seal performance through advanced simulation and material analysis. All john crane type 1 mechanical seals undergo rigorous trials, including thermal cycling and pressure tests, to ensure durability, minimal leakage, and long service life in demanding industrial environments.




Industry Solutions




Case Study
Hydraulic Oil Pump: A standard bellow seal was rupturing under pressure spikes. We installed this Type 1 O-Ring Pusher. The O-ring handled the pressure, and the spring provided the necessary torque transmission.
Testimonials
A tough John crane type 1 mechanical seal. We use it where standard bellow seals blow out.
—Hydraulic Repair Shop, USA
FAQs about John Crane Type 1 O-Ring Pusher Mechanical Seals Replacement
Q: Is this a Type 8-1?
A: No, Type 8-1 is a multi-spring O-ring seal. This is a single spring O-ring seal, keeping the non-clogging benefit of the John crane type 1 mechanical seal but with O-ring sealing.






Our company is specialized in the production of sealing materials, mechanical seals , cartridge seals.
E-mail: gechacha@aliyun.com
Mobile: +86-18758835650
WhatsApp: +86-18758835650
Add: No8-2, Jinsha road Yuelin Street, Fenghua District, Ningbo, Zhejiang