Aftermarket replacements for John Crane Type 1 (US) / Type 2 (US) | AESSEAL P05U / P04U | Vulcan A5 / A4

Luwint MT1 and MT2 are single-spring elastomer bellows mechanical seals for imperial-shaft pump applications. The MT1 corresponds to the John Crane Type 1 (US) family, while the MT2 corresponds to the Type 2 (US) family.

The two designs suit different installation spaces. MT1 has a longer, narrower rotary assembly, while MT2 uses a spring positioned around the seal head to reduce axial working length. Matching the correct design, stationary seat and materials is essential when replacing an existing seal.

Why Choose the MT1 / MT2 Range

• Two installation profiles: choose the longer MT1 or shorter MT2 to match the existing seal chamber.

• Single coil spring: provides axial loading to maintain contact between the sealing faces.

• Elastomer bellows construction: provides shaft sealing and flexibility within the rotary assembly.

• Imperial shaft sizes: supports repairs to equipment built around inch-sized shafts and sleeves.

• Face and elastomer options: allows material combinations to be selected for the liquid and operating duty.

Choosing the Correct Model

Feature	MT1	MT2
Corresponding John Crane family	Type 1 (US)	Type 2 (US)
Rotary profile	Longer axial length, smaller outside diameter	Shorter axial length, larger outside diameter
Spring arrangement	Spring extends behind the seal head	Spring surrounds the seal head
Main selection consideration	Available axial depth	Axial depth and radial clearance

For a 1-inch (25.4 mm) shaft, the Luwint catalogue lists a rotary working length, L1, of 39.7 mm for MT1 and 25.4 mm for MT2. These dimensions exclude the stationary seat.

MT1 and MT2 should not be interchanged solely because the shaft diameter matches. Check the rotary working length, maximum rotary diameter, stationary-seat outside diameter and seat thickness against the pump installation.

Typical Operating Conditions

Parameter	Luwint catalogue range or limit
Shaft sizes listed	½–4 inches (12.7–101.6 mm), in selected imperial sizes
Pressure	Up to 14 bar
Sliding speed	Up to 16 m/s
Temperature	−30°C to +200°C

Actual limits depend on seal size, face materials, elastomer, liquid and operating conditions. Maximum pressure, speed and temperature do not necessarily apply simultaneously. Confirm the proposed material combination and duty before ordering.

Common Cross-References

Manufacturer	MT1 corresponding family	MT2 corresponding family
John Crane	Type 1 (US)	Type 2 (US)
AESSEAL	P05U	P04U
Vulcan	A5	A4
Flowserve / Pac-Seal	220 / 51	52

Cross-references are a starting point for identification. Stationary-seat arrangements, working lengths and material combinations can differ between manufacturers and configurations. Confirm the complete dimensional match before selecting a replacement.

Where It Is Used in Australia

With suitable materials and a verified fit, MT1 and MT2 can be selected for:

• Water transfer and circulation pumps

• Agricultural and irrigation pumping equipment

• Wastewater transfer, subject to solids and abrasion assessment

• Industrial cooling-water and utility systems

• General process pumps handling compatible liquids

Selection should account for fluid chemistry, temperature, seal-chamber pressure and solids content, together with the available installation space.

Materials Available

The Luwint catalogue lists the following options:

• Seal faces and stationary seats: Carbon, Ceramic, Silicon Carbide (SiC), Sintered Silicon Carbide (SSiC) and Tungsten Carbide (TC).

• Elastomers: Nitrile (NBR), EPDM and Viton (FKM).

Contact Luwint to select a face pairing and elastomer suitable for the liquid, temperature and duty. Confirm the available combination for the required model and shaft size.

Sydney Supply. Help with Selection.

Contact Luwint for current stock availability, pricing and dispatch timing.

For help matching a seal, send the pump make and model, shaft or sleeve diameter, and clear photos of the old rotary assembly and stationary seat. Include the working length, rotary outside diameter, seat dimensions, liquid, operating temperature and pressure.

Ask us for the full PDF catalogue and the MT1 / MT2 dimensional drawing.

Contact: Wayne Liao
Email: wayne@luwintonline.com
Mobile: 0433 986 633

LUWINT supplies aftermarket replacement products for original equipment applications. We are an independent supplier and are not affiliated with or endorsed by John Crane, AESSEAL, Vulcan or Flowserve/Pac-Seal. Brand names and model references are used solely for identification and cross-reference.