Key Details

Whether the issue is age, wear, or contamination, the MOOG D635-120D can often be restored. NC Servo applies the same structured approach to every rebuild.

About Our Shop

Our technicians work on industrial components like the MOOG D635-120D daily. That hands-on repetition builds the kind of experience that speeds up diagnosis and reduces rework.

One-year warranty on all MOOG D635-120D valve repairs

Frequently Asked Questions

Send it in for evaluation. We’ll inspect it and give you a repair-vs-replace recommendation based on the actual condition of the unit.

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

Yes. Send us photos of the unit from multiple angles. Our team has serviced thousands of models and can often ID them visually.

You can send it as-is. We handle all cleaning and preparation as part of our standard process.

Yes, a one-year warranty is standard on all repairs. Details are provided with your service report.

Rebuild Steps

Our team disassembles each valve to assess internal wear. After ultrasonic cleaning, we install replacements and reassemble and verify operation.

  • Leak and Pressure Testing: The reassembled unit is leak-tested and pressure-tested to verify it meets published specs.
  • Cleaning: Units go through a mineral bath, with ultrasonic cleaning used for delicate internals.
  • 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.

Hydraulic Testing Process

With over a dozen dedicated flow test stands 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 functional testing verifies spec-level operation.

Technical Specifications

Every MOOG D635-120D we service is tested under operating environments. Our diagnostics verify performance against published specifications. Specification sheets and Cycle life data are available for purchase upon request.

Parts and Inventory

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.

Data Sheets & Reports

For transparent insights into your MOOG D635-120D, we can provide access to reports and repair records. This transparency offers you record-keeping and aids in long-term maintenance planning.

Maintenance Tips

  • Check valve alignment carefully to prevent undue stress on internal components.
  • Flush the hydraulic system after any major repair to remove debris before reinstalling the MOOG D635-120D.
  • Use only manufacturer-recommended hydraulic fluids to protect internal valve surfaces.

Get an Expert Repair for Your MOOG D635-120D

Request pricing, availability, and turnaround for your MOOG D635-120D. NC Servo provides independent repair with a 1-year warranty. Contact us to start 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.