491-0908 (4910908) — A hydraulic proportional solenoid valve / exhaust pressure solenoid valve for Caterpillar (CAT) New Generation GC Series excavators. Primarily utilized in C7.1 engine models, it controls hydraulic system flow and pressure regulation. Image

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I. Basic Parameters

OEM Models: 491-0908, 4910908, CA491-0908

Applicable Engine: Caterpillar C7.1

Type: Hydraulic Proportional Solenoid Valve / Exhaust Pressure Solenoid Valve

Voltage: 24V (Excavator Standard)

Interface: 2-Pin Electrical Connector

Material: Metal Body, with Green / Black Sealing Rings

Warranty: Typically 6 months for domestic aftermarket parts

II. Applicable Models (Primarily Caterpillar GC Series)

320, 320 GC

323, 326, 326 GC

330, 336, 336 GC

345 GC, 349, 352

336MH PU, 340, MH3040

III. Functions and Purpose

Installed on the Main Control Valve / Hydraulic Pump; receives signals from the ECM.

Regulates hydraulic oil flow and pressure to control boom, stick, and bucket movements.

Involved in power matching, flow distribution, and load-sensing control.

Failure Symptoms: Slow movement, lack of power, sticking/jamming, abnormal noise, warning alarms.

V. Alternative Models

585-9230, 585-9231, 485-5747

611-6430, 1013365

VI. Common Faults and Replacement Tips

Failure Phenomena: Sluggish movement, lack of power on one side, high oil temperature, diagnostic codes/alarms.

Installation Location: On the Main Control Valve (MCV), featuring a 2-pin connector.

Key Replacement Points:

Relieve hydraulic pressure; clean the mounting surface.

Replace sealing rings; ensure no impurities enter the system.

Firmly connect the electrical plug; test operation.

Clear diagnostic codes if necessary.