Type 1 Mechanical Seal
Our catalog model WM T1 is built to the John Crane Type 1 style: a rubber bellows seal with a single coil spring for pumps on inch shafts. Standard sizes run from 5/8" to 3"; other sizes are built to order.
We build most John Crane seals, not only Type 1: send the seal part number, a drawing or the old seal. All are equivalents, not sold as genuine OEM parts.
Operating limits · catalog model WM T1
Drawing & dimensions
Type 1 dimension chart
Dimensions in mm unless a table says inches. Inch sizes are named by the nominal shaft size in inches; d1 gives the same size in mm. Letters match the section drawing. Standard sizes shown; other sizes are built from a drawing or the old seal.
| Model | d1 (mm) | d3 | d7 | l1 | l3 |
|---|---|---|---|---|---|
| WMT1-5/8" | 15.872 | 27.76 | 31.75 | 43.81 | 10.29 |
| WMT1-3/4" | 19.05 | 30.6 | 34.93 | 43.81 | 10.29 |
| WMT1-7/8" | 22.225 | 35 | 38.1 | 45.43 | 10.29 |
| WMT1-1 " | 25.4 | 39 | 41.28 | 50.97 | 11.1 |
| WMT1-1 1/8" | 28.575 | 42 | 44.45 | 52.58 | 11.1 |
| WMT1-1 1/4" | 31.75 | 45 | 47.63 | 52.58 | 11.1 |
| WMT1-1 3/8" | 34.925 | 49 | 50.8 | 52.58 | 11.1 |
| WMT1-1 1/2" | 38.1 | 51 | 53.98 | 54.15 | 11.1 |
| WMT1-1 5/8" | 41.275 | 58 | 60.33 | 54.15 | 12.7 |
| WMT1-1 3/4" | 44.45 | 61 | 63.5 | 63.7 | 12.7 |
| WMT1-1 7/8" | 47.625 | 63.8 | 66.68 | 63.7 | 12.7 |
| WMT1-2" | 50.8 | 68 | 69.85 | 66.87 | 12.7 |
| WMT1-2 1/8" | 53.9 | 71.42 | 76.2 | 74.8 | 14.27 |
| WMT1-2 1/4" | 57.1 | 74.6 | 79.38 | 74.8 | 14.27 |
| WMT1-2 3/8" | 60.3 | 77.77 | 82.55 | 77.97 | 14.27 |
| WMT1-2 1/2" | 63.5 | 80.95 | 85.73 | 77.97 | 14.27 |
| WMT1-2 5/8" | 66.6 | 85.73 | 85.73 | 85.95 | 15.9 |
| WMT1-2 3/4" | 69.8 | 88.9 | 88.9 | 85.95 | 15.9 |
| WMT1-2 7/8" | 73 | 92.8 | 95.25 | 89.1 | 15.9 |
| WMT1-3" | 76.2 | 95.25 | 98.43 | 89.1 | 15.9 |
Materials
Materials of construction
- Rotary ring
- Carbon, SiC, tungsten carbide
- Stationary ring
- Ceramic, SiC, tungsten carbide
- Secondary seals
- NBR, EPDM, Viton
- Spring and metal parts
- 304 stainless, 316 stainless
Face pair and elastomer are chosen for the duty; other materials on request.
Cross-reference
John Crane Type 1
WM T1 usually corresponds to the John Crane Type 1. Check the shaft size and the working length against the old seal or its drawing before ordering; if they differ, we build to your dimensions.
Comparing Type 1 with Type 2? See the difference between Type 1 and Type 2 seals.
FAQ
FAQs
Is this a genuine John Crane part?
No. It is our own seal built to the Type 1 style and sold as an equivalent, not as a genuine OEM part.
Can you make a size that is not in the chart?
Yes. The chart lists our standard inch sizes; other sizes, metric shafts and special faces are built to order. To quote, send the seal part number, a drawing or the old seal.
What do you need for a quote?
The seal part number, a drawing or the old seal, plus the fluid, temperature and pressure if the face pair or elastomer should change.
Request a quote
Send the brand and part number, the seal drawing or a sample of the old seal. As the manufacturer we quote drop-in equivalents, custom and private-label seals at low minimums.