Hydraulic Pump Not Returning Oil? Top 5 Causes & Professional Solutions | Guangdong Haozheng Hydraulic Equipment Co., Ltd.

In hydraulic system operations, the hydraulic pump serves as the core power component, and its proper functioning is critical to overall system stability. As technical experts in the hydraulic industry, Guangdong Haozheng Hydraulic Equipment Co., Ltd. has identified hydraulic pump oil return failure as one of the most frequently reported issues by customers. This article systematically analyzes the five primary causes of this problem and provides professional solutions to help quickly restore your equipment to normal operation.

In-Depth Analysis of Five Causes of Hydraulic Pump Oil Return Failure

1. Insufficient Hydraulic Oil: Lack of System "Blood"

Symptoms: Oil level below minimum mark on tank, cavitation noise (hissing sound) at pump suction port Technical Analysis:

• For precision components like plunger pumps, insufficient oil causes poor suction and significantly reduces volumetric efficiency

• Long-term low oil operation may lead to internal component wear (e.g., valve plates, pistons) due to inadequate lubrication Solutions: √ Immediately replenish with the same grade hydraulic oil to proper level √ Check for external leaks (Guangdong Haozheng recommends using fluorescent leak detection agents)

2. System Leakage: The Hidden Danger of Pressure Loss

Symptoms: Pressure gauge shows inability to build system pressure, visible oil stains on pump body or piping Technical Analysis:

• Common leak points include: pump shaft seals, pipe connections, valve block mating surfaces

• In high-pressure plunger pump systems, minor leaks can significantly reduce system efficiency Solutions: √ Tighten all connections to specified torque using a torque wrench √ Replace aged seals (Guangdong Haozheng provides OEM seal kits)

3. Internal Pump Failure: Core Component Wear

Symptoms: Abnormal pump temperature rise accompanied by metal grinding noises Technical Analysis:

• Internal wear in plunger pumps (e.g., slippers/swashplate, valve plate/cylinder block) increases internal leakage

• Sticking variable mechanism affects normal displacement adjustment Solutions: √ Test pump volumetric efficiency (Guangdong Haozheng recommends using professional test benches) √ Replace worn components or complete pump cartridge

4. Fluid Contamination: The System's "Silent Killer"

Symptoms: Cloudy oil, frequent filter clogging Technical Analysis:

• Solid particles accelerate wear in hydraulic pump friction pairs

• Water content causes corrosion and affects sealing performance Solutions: √ Conduct oil sample contamination testing (per ISO 4406 standard) √ Replace hydraulic oil and flush system (Guangdong Haozheng offers professional oil purification services)

5. Suction Line Issues: The "Critical Path" of Oil Supply

Symptoms: Excessive vacuum at pump inlet, severe system cavitation Technical Analysis:

• Clogged suction filters increase flow resistance

• Kinked lines or undersized piping affects flow rate Solutions: √ Inspect and replace suction filters √ Ensure suction line diameter meets pump flow requirements

Preventive Maintenance Recommendations

To prevent hydraulic pump oil return failure, Guangdong Haozheng Hydraulic Equipment Co., Ltd. recommends:

1. Establish regular inspection routines (oil level, quality, seal condition)

2. Use OEM filters and seals to maintain system cleanliness

3. Perform oil analysis every 2,000 hours and replace degraded oil promptly

4. Conduct periodic efficiency tests on critical components like plunger pumps

For complex failures, we recommend contacting professional repair services. Guangdong Haozheng Hydraulic Equipment Co., Ltd. offers:

• Comprehensive hydraulic pump testing equipment

• Genuine spare parts inventory

• Experienced technical service team Providing full support from fault diagnosis to maintenance services.

(This article is provided by the Technical Department of Guangdong Haozheng Hydraulic Equipment Co., Ltd. Please credit the source when reposting. For specific repair operations, consult professional technicians.)