MOOG is a globally trusted brand in precision electrohydraulic servo valves, delivering high dynamic response and reliable flow control for industrial automation, aerospace test systems, turbine control, and metal forming machinery. As MOOG continuously improves its product portfolio, many legacy servo valve models have been phased out and replaced by newer enhanced versions. This detailed selection guide provides a complete cross reference for MOOG G771 and G772 series servo valves, listing every obsolete model alongside its officially recommended replacement. Engineers and maintenance professionals can use this information to upgrade outdated systems, ensure spare part availability, and maintain peak performance without unexpected downtime.

The MOOG G771 series covers a wide range of two stage flow control servo valves with rated flows typically from 4 to 63 LPM at 70 bar drop. Older G771K200A, G771K201A, G771K202A, G771K203A, and G771K208A have been replaced by newer variants such as G771K289A, G771K287A, G771K293A, G771K291A, and G771K294A respectively. Specifically, the MOOG G771K200A and G771K240A both upgrade to G771K289A, while G771K201A and G771K241A both cross to G771K287A. The models G771K202A and G771K242A are replaced by G771K293A. For G771K203A the replacement is G771K291A, and for G771K208A, G771K244A, both cross to G771K294A. Other important updates include G771K226A to G771K288A, G771K227A to G771K292A, G771K247A to G771K235A, and G771K260A to G771K290A. Higher flow versions such as G771K297A, G771K298A, G771K299A are replaced by G771K355A, G771K354A, and G771K356A respectively. Also, the G771K624A series (K624A, K625A, K626A) now cross to G771K305A, G771K301A, and G771K304A.

The MOOG G772 series generally features higher flow capacities and ruggedized construction for demanding mill and press applications. Obsolete models include G772K240A and G772K272A, both replaced by the newer G772K336A. Similarly, G772K241A and G772K273A both upgrade to G772K337A. The G772K340A is replaced by G772K357A. Additionally, G772K619A and G772K620A now cross to G772K339A and G772K338A respectively.

When upgrading from a legacy MOOG servo valve to a recommended replacement, users will find that the new models offer improved torque motor design, enhanced contamination tolerance, lower null shift, and in many cases compatible mounting interfaces and coil resistances. However, it is critical to verify the command signal (current or voltage), supply pressure, and flow gain characteristics before direct substitution. MOOG provides detailed specification sheets for each replacement valve to ensure seamless integration into existing closed loop control systems. For applications requiring safety certification or extreme environmental ratings, the newer MOOG valves also meet updated CE and ATEX standards where applicable.

To maintain system performance and avoid costly production stops, plant managers are strongly advised to stock recommended MOOG replacement servo valves before legacy units become completely unavailable. This cross reference guide covers all major obsolete G771 and G772 series models. For precise tuning, always consult the original valve nameplate and compare with the replacement model’s datasheet. MOOG’s global technical support can assist with validation of flow curves, step response, and frequency response when migrating to newer valve types.

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