Overview

We’ve serviced hundreds of MOOG D631-191C units over the years. Each one goes through the same controlled teardown, parts replacement, and testing process.

Independent Repair Facility

NC Servo Technology operates independently, so we’re not tied to manufacturer delays or restrictions. That means more flexibility when your system is down.

Specializing in MOOG D631-191C servo valve technology for over five decades

Frequently Asked Questions

We confirm next steps with you if a unit can’t be rebuilt. No work proceeds without your approval.

Most repairs are completed within 1 to 3 weeks, depending on workload and parts availability.

All repairs come with a one-year warranty. Contact us for specifics on your unit.

Yes. Photos of the nameplate and overall unit let us begin identification before it arrives, which speeds up the process.

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.

How We Rebuild This Valve

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 undergoes bench-testing against published performance specs.
  • Leak and Pressure Testing: The reassembled unit is leak-tested and pressure-tested to verify it meets published specs.
  • In-House Parts Sourcing: Many repairs use components sourced from our inventory of 17,000+ units.
  • Cleaning: Units go through a mineral bath, with ultrasonic cleaning used for delicate internals.

Diagnostic Testing

With our 13-stand test facility and a Hagenbush proportional valve system, we verify flow curves, hysteresis, frequency response, and more. Performance reports and graphs are available for purchase on request. Our operational testing verifies spec-level operation.

Repair, Rebuild and Exchange Options

Beyond standard refurbishment, we offer specialized overhauls for your MOOG D631-191C unit. Our teardown process includes internal inspection and mineral bath cleaning, using only new replacement components.

In-House Inventory for MOOG D631-191C

With more than 17,000 valve units in inventory, we can often provide faster turnaround by sourcing parts in-house rather than waiting on OEM lead times.

Maintenance Tips

  • Check system pressure regularly to verify it stays within the MOOG D631-191C rated operating range.
  • Inspect MOOG D631-191C seals regularly to prevent leaks and maintain performance.
  • Document all maintenance activities to track performance trends over time.

Get a Free Evaluation for Your MOOG D631-191C

Request pricing, availability, and turnaround for your MOOG D631-191C. NC Servo Technology provides independent repair with a 1-year warranty. Contact us to schedule your repair.

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NC Servo Technology 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.