Inspection and Repair Process

Each MOOG D631-404C undergoes reconditioning — disassembly, parts replacement, reassembly, and bench testing before shipment.

Why Repair With NC Servo

Unlike OEM shops, we use our own inventory to handle most rebuilds. That cuts down on lead time and gets your unit back faster.

Frequently Asked Questions

Yes. Every unit goes through diagnostic testing and we provide an assessment before moving forward.

If the main housing or board is intact, repair is usually the better option. We can restore most units to working condition with tested parts.

Yes, rush service is available for an additional fee. Let us know your deadline when you submit your request.

Even if the tag is worn off, we can often match the unit based on shape, size, and internal configuration.

If a unit is beyond repair, we explain why and can discuss replacement or exchange options.

Repair Process

The process begins with disassembly and visual evaluation. We then clean, replace worn pieces, and reassemble the valve to restore its function.

  • Final Performance Verification: After reassembly, each valve is bench-tested against published performance specifications.
  • Cleaning: Units go through a mineral bath, with ultrasonic cleaning used for delicate internals.
  • Teardown: Every valve is disassembled for internal inspection.
  • Seal and Gasket Replacement: Worn seals and gaskets are replaced with new components during every rebuild.

Diagnostic Testing

NC Servo operates thirteen in-house test stands, including setups for proportional and servo valves. Every valve goes through performance and leak testing using industry-standard fluids including MIL-5606 and Skydrol. Our performance testing verifies proper functionality.

Performance Data

Every MOOG D631-404C we service is tested under typical applications. Our diagnostics verify performance against published specifications. Technical diagrams and Specification sheets are available for purchase upon request.

Repair, Rebuild and Exchange Options

Beyond standard sales, we offer specialized reconditioning for your MOOG D631-404C unit. Our teardown process includes spool evaluation and reassembly to spec, using only replacement replacement components.

Turnaround and Shipping

As a dedicated source for MOOG D631-404C services, NC Servo targets quick resolution with typical lead times of 2 to 3 weeks. Benefit from our responsive technical support to keep your systems running smoothly.

Technical Information

For documented insights into your MOOG D631-404C, we can provide access to reports and service logs. This transparency offers you compliance assurance and aids in long-term maintenance planning.

Maintenance Tips

  • Store spare MOOG D631-404C valves in a clean, dry environment to prevent corrosion and contamination.
  • Document all maintenance activities to track performance trends over time.
  • Conduct thorough visual inspections for wear or leaks during routine maintenance.

Request a Quote for Your MOOG D631-404C Maintenance

Request pricing, availability, and turnaround for your MOOG D631-404C. NC Servo provides warrantied repair with a 1-year warranty. Contact us to request your repair.

Request a Quote View All MOOG Products Shop MOOG Inventory

NC Servo is an independent third-party repair facility. We are not affiliated with, endorsed by, sponsored by, or authorized by MOOG or any original equipment manufacturer (OEM), nor do we claim to be a MOOG service center. All brand names, trademarks, model numbers, and part numbers referenced on this page are the property of their respective owners and are used solely for identification and compatibility purposes.