Pilot stage rebuild
Nozzle flapper and torque motor pilot stages cleaned, aligned, and trimmed. Null bias verification on the hydraulic stand.
Flight Simulator Motion Base Servo Valve Repair
Independent third-party repair of servo valves used in 6-DOF Stewart platform motion bases on commercial and military flight simulators. Component-level rebuild and bench testing on Moog, Parker, Rexroth, and Vickers servo valves used by CAE, FlightSafety, L3Harris, Frasca, and TRU training systems.
Where These Valves Sit
Four motion-base application contexts
Below are common simulator types and the servo valves that come off them for rebuild.
01
Full Flight Simulators (FFS)
Type D and Type C full-flight simulators. Moog 728, 760, and 72 series servo valves come off these for rebuild.
02
Flight Training Devices (FTD)
Advanced FTDs and lower-fidelity motion devices. Parker D1FP and Rexroth 4WS servo valves come through for component-level rebuild.
03
Military flight simulators
Fighter, transport, and rotary-wing motion platforms. Moog 760 and Vickers SM-4 servo valves come off these.
04
Legacy & out-of-support simulators
Discontinued Moog 72, older Parker D1FP, and early Rexroth 4WS valves come off simulators 15-25 years old where OEM support is limited.
What NC Servo Does
Component-level repair on motion-base valves
Each unit is opened, inspected, and rebuilt at the component level. Failed parts are pulled from inventory or from donor units in the in-house pool. Bench verification before ship.
Spool & sleeve service
Spool wear, contamination scoring, lap restoration, and internal leakage checks on simulator-grade valve bodies.
Coil & feedback work
Burned drive coil rebuild, feedback wire repair, and LVDT verification on closed-loop servo valve bodies.
Bench testing
Hagen-Busch and older-style hydraulic stands. Frequency response, hysteresis, null shift, and step response data on request.
Donor parts service
Stock is hit or miss, but legacy simulator hardware shows up often enough that we can pull from past jobs when we have a match. Ask about a specific part number.
Repair scope
Component-level hardware work only. Simulator qualification, FAA / EASA sign-off, and motion tuning stay with the customer or training-center integrator.
Brands
Servo valve brands on simulator motion bases
Top brands seen on commercial and military flight-simulator motion platforms. Click through for the dedicated brand page.
Common Faults
What usually shows up on motion-base valves
Common failure modes seen on motion-base servo valves at the bench.
| Pilot stage | Nozzle plugging, flapper damage, jet alignment after a contamination event, and pilot-pressure null shift after long service. |
|---|---|
| Spool and body | Spool wear, contamination scoring on lap surfaces, sticky spool action, and internal leakage past the spool. |
| Coil and feedback | Burned drive coils after surge events, feedback wire wear, LVDT signal drift, and signal-path component failures. |
| Connector and electrical | Damaged connectors, cable strain at the entry point, contamination on the connector pins after years of motion-base service. |
Workflow
From part number to ship-back
Same four-step path through the shop whether the unit came off a Type D commercial simulator or a 25-year-old military training device.
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01
Get in touch
Call or email with the part number, simulator make, and a photo of the nameplate if it helps.
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02
Bench review
Tech opens the unit, inspects pilot and spool, and runs it on the hydraulic stand to confirm what failed.
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03
Cost & approval
We call back with the cost and a rough turnaround. Nothing is started without your sign-off.
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04
Repair, test, ship
Failed components replaced from inventory or off donors, valve verified under pressure, and shipped back.
FAQ
Common questions about motion-base valve repair
Application-specific questions. For brand-specific FAQs, see the dedicated brand page in the brand list above.
What types of flight simulator servo valves do you repair?
Servo valves used in 6-DOF Stewart platform motion bases: Moog 728, 760, 72, and D633 series; Parker D1FP and D3FP; Rexroth 4WS and 4WRPH; and Vickers SM-4. All come off the bench for rebuild.
What simulator brands do these valves come off of?
CAE, FlightSafety International, L3Harris, Frasca, TRU Simulation + Training, Thales, Indra, Alsim, and Precision Flight Controls. NC Servo is not affiliated with any simulator OEM. We service the valve hardware that comes through the bench.
Can you repair valves from older simulators no longer supported by the OEM?
Yes. Discontinued Moog 72-series, older Parker D1FP models, and early Rexroth 4WS valves are common at the bench. Stock for legacy simulator hardware is hit or miss, but parts often turn up from past jobs when we have a match. Ask about a specific part number.
Do you provide motion-base programming or simulator parameter setup?
No. NC Servo handles bench-level component repair on the valve hardware only. PLC programming, motion-controller setup, motion-cue tuning, and simulator qualification stay with the customer or training-center integrator.
Do you provide test data with the repair?
Each repaired valve is bench-tested before it ships. Frequency response, hysteresis, null bias, step response, and other performance data are available on request.
How long does a repair usually take?
Lead time varies job to job, partly because parts are often pulled from donor boards. Give us a call with the part number and the situation.
What is the warranty?
One year on parts and workmanship for repairs and rebuilt units. Standard exclusions apply for contamination, improper installation, and out-of-spec operation. Flushing and filtering the hydraulic system before reinstalling a repaired valve is recommended.
More from NC Servo
Related repair coverage
The aerospace hub, related industry pages, and the brand pages most-tied to flight-simulator motion bases.
Aerospace hub
Full aerospace coverage: simulators, control loading, motion bases, hydraulic test stands, GSE.
Control loading repair
Yoke, rudder, and throttle force-feedback systems on commercial and military simulators.
Moog brand page
Moog 728, 760, 72, and D633 servo valves: simulator and aerospace hardware coverage.
Parker brand page
Parker D1FP and D3FP servo valves on flight training devices and motion platforms.
Bosch Rexroth brand page
Rexroth 4WS and 4WRPH servo valves on heavy commercial and military motion bases.
Valve repair hub
Full directory of 20+ valve brands with dedicated pages.
What is a servo valve?
Plain-English explainer on what's inside an electrohydraulic servo valve.
How to test a servo valve
Bench testing workflow on the hydraulic stand: flow, pressure gain, null, leakage, and step response.
Simulator grounded? Send a part number
Give us a call or send a part number with the simulator make and the symptom. We'll check the donor pool, suggest a rebuilt match if we have one, and walk through repair or cross-brand options if we don't.