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Analysis of mud pump failure

Troubleshooting Guide for Mud Pump Failures

1. Failure to Start after Water Supply

Reason Analysis:

  1. Presence of sand particles, cement agglomerates, and debris around the suction valve preventing proper closure.
  2. Damage to O-ring on the suction valve seat.
  3. Improper fitting or absence of gaskets on three discharge plugs under the pump head.
  4. Air trapped in the suction path and pump chamber due to new pump installation or extended downtime.
  5. Blockage in the inhalation channel or inlet.


  1. Clear debris around the suction valve and rinse with clean water.
  2. Replace damaged O-ring on the valve seat.
  3. Ensure proper sealing and tightness of discharge plugs under the pump head.
  4. Release air from the system by loosening the unloading valve or running the pump at lower speed to remove air bubbles.
  5. Unblock the inhalation channel.

2. Motor Failure to Rotate

Reason Analysis:

  1. Insufficient engine speed, inadequate fuel supply, or low hydraulic system pressure.
  2. Faulty hydraulic system supplying the mud pump or low relief valve pressure causing insufficient supply pressure.
  3. Malfunctioning hydraulic motor.
  4. Incorrect shift gear position or unlocked positioning device.
  5. Faulty crankshaft or connecting rod.


  1. Increase engine speed of main pump station (n ≥ 1500 r/min), enhance fuel supply, and boost hydraulic system pressure (above 10 MPa).
  2. Collaborate with maintenance personnel to identify and rectify issues in the hydraulic system.
  3. Inspect and repair the hydraulic motor on the mud pump.
  4. Ensure proper gear position and lock the positioning device.
  5. Examine and replace damaged components.

3. Flow and Pressure Fluctuations

Reason Analysis:

  1. Debris accumulation around the ball valve causing incomplete closure.
  2. Damage to O-ring on the suction valve seat.
  3. Excessive piston wear or damage leading to slurry leakage.
  4. Leaks due to seal failure in suction passage or loose/missing seals in pump head.


  1. Remove debris around the ball valve to ensure proper closure.
  2. Replace the damaged O-ring on the valve seat.
  3. Adjust piston or replace it to mitigate slurry leakage.
  4. Verify and ensure proper sealing in the suction passage.

4. Pump Body Noise

Reason Analysis:

  1. Incorrect gear position or unlocked positioning device.
  2. Inadequate adjustment of clearance between shafts and crankshaft.
  3. Excessive wear in connecting rod’s head bearing, resulting in increased clearance.
  4. Deformation, damage, or misalignment of crankshaft, connecting rod, or gears.


  1. Ensure proper gear engagement and lock the positioning device.
  2. Adjust clearance between shafts and crankshaft to optimize operation.
  3. Modify spacers or replace worn bearings in connecting rod halves.
  4. Inspect and replace damaged parts.

5. Excessive Crankcase Temperature Rise

Reason Analysis:

  1. Overfilled crankcase with excessive oil.
  2. Insufficient oil film due to large gaps in connecting rod bearings.
  3. Tight bearing clearances at both ends of two-axis and crankshaft.


  1. Adjust oil level to nominal position and drain excess oil from the cabinet.
  2. Add 0.1mm spacers to big connecting rod joints for proper bearing lubrication.
  3. Optimize bearing clearances between two-axis and crankshaft.

6. Other Faults

Oil Leakage or Leakage at Pump Outlet Hole:

  • Cause Analysis: Damage to J-ring seal or excessive oil injection.
  • Remedies: Replace J-ring and adjust oil level.

Pressure Gauge not Displaying:

  • Cause Analysis: Leaked oil in the damper or damaged rubber diaphragm.
  • Remedies: Tighten pressure gauge, refill damper with oil, replace rubber diaphragm.

Slurry Leakage at Cylinder Head or Valve Cover:

  • Cause Analysis: Damaged cylinder head or bonnet O-ring.
  • Remedies: Replace O-ring after applying lubrication.

Leakage from Safety Valve:

  • Cause Analysis: Damaged steel ball, rust, or debris around safety valve.
  • Remedies: Replace ball/seat, clean rust, remove debris.

Pump Pressure not Increasing:

  • Cause Analysis: Low engine speed, insufficient fuel supply.
  • Remedies: Increase engine speed, enhance fuel supply.

Inadequate Pressure Gauge Reading:

  • Cause Analysis: Leaked oil or damaged diaphragm in damper.
  • Remedies: Secure pressure gauge, refill damper, replace diaphragm.

Summary: This guide highlights various mud pump failures, their causes, and corresponding remedies. It aims to raise awareness among construction owners and operators to ensure timely project completion and maximize project benefits.

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