How We Repair Your Unit

We specialize in the overhaul of your MOOG D631-398C, including the replacement of all necessary seals and worn components.

Experience and Warranty

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

17,000+ valves in stock including MOOG D631-398C exchange units

Frequently Asked Questions

Rush and priority service options exist. Availability depends on current workload, so contact us early.

Yes. Our technicians can often identify units based on photos, dimensions, or manufacturer markings. Send a photo before shipping to speed up intake.

Not required, but removing excess oil or loose debris before packing helps keep things clean in transit.

All repairs come with a 12-month warranty on parts and labor. Contact us for specifics on your unit.

Photos help us confirm the unit type and speed up intake. You can upload them through our quote request form.

Disassembly and Rebuild Procedure

We disassemble every valve, inspect it inside and out, and clean all moving parts. Components that fail inspection are swapped out before the valve is rebuilt and tested.

  • Leak and Pressure Testing: The reassembled unit is leak-tested and pressure-tested to verify it meets published specs.
  • Seal and Gasket Replacement: Worn seals and gaskets are replaced with new components during every rebuild.
  • 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

We carry out full diagnostics on every valve, including flow gain, leakage, pressure shift, and frequency testing. Our test facility supports performance logging and report generation. Our performance testing verifies consistent performance.

Where the MOOG D631-398C Is Used

Our reliable repair services for the MOOG D631-398C are trusted across various sectors including Steel & Metals, Power Generation, and Oil & Gas. We understand the unique demands of valves in these environments.

Repair, Rebuild and Exchange Options

Beyond standard sales, we offer specialized reconditioning for your MOOG D631-398C unit. Our disassembly process includes bench testing and spool evaluation, using only new replacement components.

Lead Times and Support

As a specialist for MOOG D631-398C services, NC Servo Tech targets quick resolution with typical lead times of 2 to 3 weeks. Benefit from our responsive technical support to keep your systems running smoothly.

Stock Availability

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

  • Schedule preventive maintenance intervals based on duty cycle, not just calendar time.
  • Keep hydraulic fluid clean and at proper levels for consistent valve operation.
  • Conduct thorough visual inspections for wear or leaks during routine maintenance.

Get a Free Evaluation for Your MOOG D631-398C

Request pricing, availability, and turnaround for your MOOG D631-398C. NC Servo Tech provides hands-on repair with a 1-year warranty. Contact us to request your repair.

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NC Servo Tech 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.