DTH Drilling Machine Hydraulic System Maintenance Guide | XinHao Drilling Rig

DTH Drilling Machine Hydraulic System Maintenance: 6 Key Steps to Avoid Costly Failures

The hydraulic system is the power heart of any dth drilling machine. It controls drilling, lifting, rotation, and travel functions.
In harsh mining and quarry environments — dust, vibration, extreme heat or cold — hydraulic systems are often the first to fail.

Why can some teams keep a dth rig machine running smoothly for over 5 years, while others face frequent leaks, pressure loss, and downtime?
The answer is not just “changing oil”, but systematic and precise maintenance.

This guide breaks down 6 proven hydraulic maintenance steps, helping you prevent over 90% of common hydraulic failures in dth rotary drilling operations.

1. Hydraulic System Preparation Before Maintenance

Safety First: Prevent High-Pressure Oil Accidents

Before any maintenance on a XinHao Drilling Rig or other DTH rigs:

• Shut down the machine and let it cool for 15–20 minutes

• Ensure hydraulic oil temperature is below 40°C

• Release residual pressure via the relief valve

• Slowly loosen the hydraulic tank cap

• Wear oil-resistant gloves and protective goggles

⚠️ Never touch pressurized hydraulic hoses directly — high-pressure oil injection is extremely dangerous.

Essential Tools & Consumables

Prepare the right tools to avoid secondary damage:

• Torque wrench (for correct bolt tightening)

• Hydraulic hose spanner

• Oil filter wrench

• Oil level gauge & oil temperature gauge

Recommended consumables:

• Anti-wear hydraulic oil ISO VG 46 or 68

• New filters (suction, return, tank filter)

• Spare O-rings (fluororubber preferred)

2. Hydraulic Oil Replacement: When and How

Oil Change Interval: Time or Working Conditions?

• Normal conditions: every 2000 working hours or 12 months

• Harsh conditions (high dust, high temperature, heavy load): every 1000 hours

For dth drilling machine working in mines or quarries, shorter intervals significantly reduce pump and valve wear.

Correct Oil Replacement Steps

1. Drain old oil completely from the tank

2. Remove drain plug and clean metal particles and sludge

3. Reinstall drain plug securely

4. Fill new hydraulic oil to the correct level

5. Run the machine idle for 5 minutes

6. Recheck oil level and top up if necessary

❗ Important: Never mix different brands or oil grades — chemical incompatibility may damage seals and valves.

3. Hydraulic Filter Maintenance: Often Overlooked but Critical

Blocked filters are a major cause of hydraulic failure in dth rig machines.

Recommended Filter Replacement Frequency

• Return oil filter: every 500 hours

• Suction filter: every 1000 hours

• Tank air breather filter: clean every 300 hours, replace every 1000 hours

How to Identify Filter Problems

• Excessive metal debris → possible pump or motor wear

• Severe blockage → contaminated oil or incorrect filter type

Always clean the filter seat before installation and tighten using the specified torque.

4. Hydraulic Oil Leakage Inspection and Repair

Common Leakage Points

• Hose connections

• O-rings and seals

• Hydraulic valve blocks

• Cylinder rod seals

Leak Detection Method

Apply soap water to suspected areas and pressurize the system.
Bubbles indicate leakage — never use hands to check leaks.

Proper Solutions

• Loose fittings → retighten with torque wrench

• Seal leakage → replace with fluororubber seals

• Hose damage → replace with original high-pressure hoses

🚫 Temporary tape repairs are unsafe and prohibited.

5. Key Hydraulic Component Checks

Hydraulic Pump & Motor

Signs of wear include:

• Abnormal noise (whining or knocking)

• Pressure lower than rated 16–25 MPa

Low pressure without leakage often means internal pump wear.

Hydraulic Valve Block

• Clean valve spools every 1000 hours

• Remove dirt and debris using clean diesel

• Check springs and seals for deformation

Hydraulic Cylinder Care

• Clean piston rods after work

• Polish minor scratches with fine sandpaper

• Apply anti-rust oil during long-term storage

6. Hydraulic Maintenance Under Different Working Conditions

High Temperature (≥45°C)

• Clean oil cooler regularly

• Use high-temperature hydraulic oil

• Avoid long-time overload operation

Cold Climate (≤ -10°C)

• Use low-temperature hydraulic oil

• Preheat engine for 5 minutes

• Insulate hydraulic tank if necessary

High Dust Environment

• Install high-efficiency air breather filters

• Maintain clean tools and working areas

• Prevent dust from entering oil tank

Common Maintenance Mistakes to Avoid

• Only topping up oil instead of replacing contaminated oil

• Using standard seals instead of hydraulic-specific seals

• Ignoring oil cooling systems

• Skipping air bleeding after maintenance

These mistakes can dramatically shorten the life of your dth rotary drilling system.

Conclusion: The Real Secret of Long-Lasting Hydraulic Systems

Reliable hydraulic performance is not luck — it comes from
regular oil changes, timely filter replacement, leak prevention, and component inspection.

For contractors and mining operators, every hour of downtime costs money.
With proper maintenance, a XinHao Drilling Rig hydraulic system can operate over 5 years with high efficiency and low failure rate — even in extreme environments.