Komatsu Part PILOT VALVE 702-21-57700

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Product Overview

The 702-21-57700 PILOT VALVE is a genuine Komatsu OEM replacement pilot valve from the 702 prefix series. Pilot valves generate the low-pressure hydraulic signals that control the main directional control valves — they're the interface between the operator's hand or foot and the powerful machine movements directed by the main valve spools. As the operator moves a control lever, the pilot valve meters a precisely proportional pressure to one end of the main spool, which shifts in response to direct pump flow to the working cylinder or motor.

Part Number: 702-21-57700 Part Name: PILOT VALVE Part Type: OEM Komatsu Replacement Component Availability: In stock

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When to Replace

• The machine function responds sluggishly, jerkily, or not at all to control input
• A specific function drifts or creeps when the control is in neutral
• Hydraulic oil visibly leaking from the pilot valve body, spool ends, or around the handle boot
• The joystick or pedal feels loose, has dead spots in its range, or doesn't return to center
• Internal leakage confirmed through pressure testing

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Installation

1. Confirm 702-21-57700 in your Komatsu parts catalog
2. Clean the mounting surface and all pilot line ports
3. Install new O-rings or seals on every connection point
4. Position and secure the pilot valve — tighten fasteners in sequence to torque
5. Connect pilot lines — verify each line routes to the correct port per the schematic
6. Bleed air from the pilot circuit — cycle functions slowly
7. Test all functions — verify smooth, proportional control

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