The hydraulic system is the heart of any excavator. It’s responsible for the movement of the boom, bucket, undercarriage, and the operation of auxiliary equipment. When buying used machinery, it’s crucial to understand the condition of the hydraulics: sometimes it will last for several more seasons, and sometimes it will require expensive repairs immediately after purchase. Let’s break down how to determine the system’s current lifespan and what signs to look out for.

How an Excavator’s Hydraulics Work

First, it’s important to understand how an excavator’s hydraulics work. A special fluid circulates under high pressure, created by a pump. Through distributors, it’s supplied to the actuators—cylinders, hydraulic motors, etc. Every element, from hoses to valves, plays a critically important role. The wear of one component affects the entire system.

Signs of Healthy and “Dying” Hydraulics

There are several parameters by which you can assess the condition of the hydraulic system:

1. Pressure Stability.

If the pump consistently maintains working pressure without jumps or drops, that’s a good sign. A drop in pressure could indicate wear in the pump group or internal leaks.

2. Response to Controls.

Delayed reaction of the boom or bucket to joystick movements can indicate worn valves, contaminated fluid, or damaged high-pressure hoses (HPH).

3. External Leaks.

Traces of oil on connections, cylinders, or the pump are an alarming symptom. In used equipment, slight “sweating” is permissible, but not active leaks.

4. Operation with Warm Oil.

Many malfunctions only become apparent after 15–20 minutes of operation when the fluid heats up. It’s important to assess the system not just “cold.”

What an Excavator’s Hydraulic Diagram Might Hide

Visual inspection often doesn’t provide a complete picture. It’s necessary to study the excavator’s hydraulic diagram to understand where problem areas might exist: rare valves, complex circuits, non-standard connections. This is especially relevant for imports from Asia or the USA—repairs might require non-standard spare parts.

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Excavator Hydraulic Repair: When Is It Justified?

Repairing an excavator’s hydraulics is an expensive undertaking, but sometimes it’s advisable. If the rest of the machine is in excellent condition (engine, undercarriage, frame), replacing the pump group or HPH can extend its service life by years. However, in cases of multiple internal leaks, cylinder deformation, and a worn distributor, it’s better to abandon the purchase.

Why It’s Especially Important to Check Wheeled Models

For wheeled chassis equipment, such as a used wheeled excavator, the condition of the hydraulics is doubly critical. It’s responsible not only for the working attachments but also for steering, stabilization, and even braking in some models. Even the slightest malfunction can lead to an emergency.

When Is It “Alive,” and When Is It Not?

A healthy hydraulic system is indicated by:

  • smooth operation without “howling” sounds or jerks;
  • clean oil without emulsion or a burning smell;
  • smooth control of all functions;
  • normal fluid temperature even after load.

If deviations are observed, there’s a high risk of imminent failure, especially if the service history is unknown.

Where to Buy Equipment with Healthy Hydraulics

Buying equipment with a healthy hydraulic system is not luck, but the result of professional selection. At TAD Group, we meticulously inspect the excavator’s hydraulics, assess pressure, take oil samples for analysis, and check the lifespan of each key component. This allows our clients to purchase machines that will work immediately and without additional investments.

If you are looking for reliable used special equipment with guaranteed condition, contact TAD Group—we will help you choose a machine for your specific tasks without hidden problems.