Confirm the Mark III Group 1 Configuration Before Ordering
A “Group 1 shaft and sleeve” request is a useful starting point, but it does not identify every installed arrangement. Before selecting a replacement, confirm the complete pump size and nameplate, the shaft arrangement, whether a sleeve is fitted, the seal configuration, and the drawing or parts-list revision for the unit being serviced.
Start with the installed assembly
Record the pump model and size, serial or nameplate data, applicable parts-list reference, shaft/sleeve arrangement, seal details, speed, process fluid and operating temperature. Use those records to determine which dimensions and materials must match.
This guide explains component identification and replacement checks. It does not provide a universal Group 1 shaft drawing, a dismantling procedure, or a guarantee that one assembly fits every Mark III Group 1 pump.
Identify the Shaft, Optional Sleeve and Sealing Arrangement
In the Flowserve Mark 3 ASME/ANSI Group 1 parts list, Item 2100 identifies the shaft and Item 2400 identifies an optional sleeve. Item numbers locate components in a parts list; they are not, by themselves, enough to select an orderable replacement or confirm dimensional interchangeability.
| Parts-list item | Listed component | What to verify for replacement |
|---|---|---|
| 2100 | Shaft | Exact pump size and shaft configuration; bearing journals; coupling end; keyway, threads and shoulders; seal-running surfaces; drawing revision. |
| 2400 | Sleeve, optional | Whether the installed unit uses a sleeve; sleeve length and interface dimensions from the applicable drawing; seal surface; material and any associated sealing parts. |
| 4130 | Packing, optional | This is gland packing in the listed Mark 3 parts breakdown. Do not treat it as a shaft-sleeve O-ring or sleeve gasket. |
| 4610.1 / 4610.2 | Adapter / bearing-carrier O-rings | These listed O-ring locations are not a generic shaft-sleeve sealing specification. Confirm the exact seal arrangement and parts list. |
Do not order from an item number alone
OEM item numbers describe positions in a particular parts list. The full pump size, configuration, material, revision and mating dimensions still determine the correct replacement reference.
For a listed OEM number or replacement reference, use the ANSI Pumps Pro OEM part-number cross-reference. Its listed matches are a lookup aid; final fit must still be verified against the installed configuration.
Sleeved Shaft or Solid Shaft: Verify the Arrangement, Do Not Assume an Upgrade
Mark 3 shaft options and sleeve arrangements can differ by pump configuration. Flowserve describes solid-shaft options and notes their potential to reduce the effects of shaft deflection and vibration. That design rationale does not make a solid shaft a direct substitute for every sleeved arrangement.
The pump drawing, shaft, sleeve and mechanical-seal interfaces match the approved replacement scope.
An engineering review has checked the shaft, bearing locations, impeller retention, seal, coupling, materials and all affected interfaces together.
Group designation alone, a cartridge-seal description, a shared nominal shaft diameter, or a general statement about stiffness.
Where the original records are incomplete, send the nameplate, clear photographs, available drawings and the installed seal details for review before specifying a configuration change.
What Must Match Between the Shaft, Sleeve and Pump?
Dimensional review should compare like-for-like features at defined datums. Record the measurement location, method and drawing reference with each result; a single runout value without its datum and setup is not a complete acceptance criterion.
Confirm Mark 3 ASME/ANSI, Group 1, complete pump size, serial or nameplate details, and the correct standard or special configuration.
Compare journal diameters, fits, shoulders, surface condition and axial locations with the applicable shaft drawing and bearing arrangement.
Verify shaft extension, keyway, thread or other retention feature, coupling fit and the installed motor/coupling arrangement.
Where a sleeve is fitted, check its ID/OD, length, seal-running surface and any sealing feature against the approved drawing and seal documentation.
Confirm the setting reference and assembly procedure for the installed reverse-vane or other impeller configuration. Do not transfer a clearance from another pump family.
Record runout and finish only with the specified measurement location, support/setup, instrument and acceptance source. Keep the inspection record with the quoted scope.
Replace Only the Sleeve or Review the Complete Rotating Assembly?
A sleeve replacement may be reasonable when the shaft remains within the approved drawing limits and the sleeve interfaces, sealing arrangement and impeller retention are understood. A sleeve alone should not be selected merely because it is the visibly worn component.
Photograph the shaft, sleeve, seal-running area, impeller interface and any corrosion, fretting, scoring or leakage path before cleaning.
Compare shaft journals, sleeve fit, seal surface and axial features with the applicable drawing and documented acceptance criteria.
Look for wear or damage on the shaft beneath the sleeve, bearing-seat damage, seal leakage, evidence of rubbing and material loss.
Choose sleeve-only, shaft-only or a matched assembly only after confirming the configuration, condition and required interfaces.
Do not claim that a new sleeve guarantees zero leakage or that every worn sleeve requires a complete shaft assembly. The condition of the shaft, fit, surface, sealing arrangement and service environment determines the repair decision.
Select Sleeve Material From the Actual Service and Material Form
Material selection depends on the complete process environment, not just the fluid name. Record concentration, normal and upset temperatures, impurities, chlorides or other relevant contaminants, solids, velocity and operating history. Then confirm the exact material specification and product form for the part being supplied.
| Material family mentioned in the current page | Review before specifying |
|---|---|
| 316 stainless steel | Confirm the exact product form and grade, process chemistry, temperature and chloride exposure. |
| CD4MCuN duplex stainless steel | Confirm casting or wrought specification, heat treatment, traceability, chemistry and the actual service conditions. |
| Alloy 20 family | Distinguish wrought Alloy 20 / UNS N08020 from cast pump-component grade CN7M; verify concentration, temperature and impurities. |
| C-276 family | Confirm exact alloy and product form, specification, heat traceability and chemical-service conditions. |
This table is a document-review checklist, not a chemical compatibility chart. For detailed screening, see the chemical resistance guide and the Alloy 20 and C-276 selection guide. Final material approval should use conditions and specifications applicable to the exact part.
Specify the Inspection Records Needed for the Replacement
Inspection and material documents should be agreed in the quotation and purchase scope. Availability and acceptance criteria depend on the ordered configuration; do not imply that every certificate or test is included unless it is confirmed for that order.
Identify the controlled drawing, pump size, configuration, material and revision used for the fitment review.
Specify the features, datums, measurement method and acceptance limits that matter to the shaft, sleeve, bearings, coupling and seal.
State the required material designation, product form, heat or lot traceability and material test report scope.
Request positive material identification or other testing when required by the project specification, and confirm the method and report before order release.
When dynamic balancing is part of the scope, specify the applicable assembly, method and acceptance grade in the quotation documents.
Document any approved deviation, assumption or excluded interface so it is not mistaken for a verified match.
What to Send for a Group 1 Shaft and Sleeve Review
A useful review starts with the installed pump and the part to be replaced. If a dimension or OEM reference is unavailable, send the records you have and identify the missing information rather than estimating it.
Nameplate photograph, complete pump size, group, serial number and applicable parts-list or drawing revision.
OEM reference or parts-list item, whether the requested scope is shaft, sleeve or a matched assembly, and quantity.
Available dimensions, shaft/sleeve photos, bearing and coupling details, seal model and seal-chamber configuration.
Speed, process fluid, concentration where applicable, normal and upset temperatures, solids and known corrosion or wear history.
Material specification, traceability, dimensional inspection, PMI, balancing or other project records required for acceptance.
For a listed part number, start with the OEM part-number cross-reference. If the installed configuration or required scope is uncertain, use the Durco Mark III replacement review path and submit the nameplate, drawing or photographs for verification.
Frequently Asked Questions
Can I replace only the sleeve on a Durco Mark III Group 1 pump?
Possibly, if the installed configuration uses the optional sleeve and the shaft, sleeve fit, seal-running surface, sealing arrangement and impeller interface meet the applicable drawing requirements. Inspect the shaft before approving a sleeve-only repair.
Does Item 2400 identify every Group 1 sleeve I can order?
No. Item 2400 identifies the optional sleeve position in the Mark 3 parts list. Pump size, configuration, material and drawing revision determine the correct orderable reference and fit.
Is Item 4130 the O-ring between the shaft and sleeve?
No. In the referenced Mark 3 ASME/ANSI parts breakdown, Item 4130 is optional gland packing. Confirm any sleeve-related sealing part from the applicable drawing and seal arrangement.
Does a 0.001-inch runout figure apply at the sleeve outside diameter?
Not automatically. Runout criteria depend on the measurement location, setup and governing drawing or specification. A value stated for the shaft at the seal chamber should not be moved to the sleeve OD or attributed to ASME B73.1 without supporting documentation.
Can a solid shaft replace a sleeved shaft because it is stiffer?
Not without a configuration review. Shaft arrangement, impeller and coupling interfaces, bearings, mechanical seal and all affected dimensions must be checked together.
What should I provide when I do not know the shaft dimensions?
Provide the pump nameplate, complete size, serial number, part-list reference, photographs, seal details and any available drawing. The required dimensions can then be identified against the correct configuration.
Technical References and Related Verification
- Flowserve, Durco Mark 3 ASME/ANSI User Instructions, PUIOM000712–00 (EN), formerly 71569102. Use the applicable revision and pump configuration.
- Flowserve, Durco Mark 3 ASME/ANSI Maintenance Checklist. Includes configuration-related operating and maintenance reference values.
- Flowserve, Durco Mark 3 Sealed ASME (ANSI) Chemical Process Pump. Product-family and available-configuration overview.
- ANSI Pumps Pro, OEM Part Number Cross-Reference. Lookup support; confirm the installed configuration before ordering.
- ANSI Pumps Pro, How to Verify a CD4MCuN Shaft Sleeve for ANSI Process Pumps. Material form, dimensional and inspection review.
