WSHT Mining Group
WSHT Mining Group
Maintenance & Troubleshooting

Hydraulic System Maintenance — Oil, Filters and Common Repairs

A practical guide to hydraulic system maintenance for mining equipment covering oil selection and change intervals, filter replacement, leak repair, troubleshooting common hydraulic problems and preventive maintenance schedules.

WSHT Mining Group
Senior Mining Engineer
· 2026-06-24 · 2 min read
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Hydraulic System Maintenance Guide

Hydraulic systems power many mining machines including crushers, screens and material handling equipment. Proper hydraulic maintenance ensures reliable operation and extends component life.

Hydraulic Oil Maintenance

Oil is the lifeblood of any hydraulic system. Oil quality directly affects system performance and component life.

Oil Change Intervals:

  • Initial change: 500-1000 hours (break-in period)
  • Subsequent changes: 2000-4000 hours
  • Severe conditions: More frequent changes
  • Best practice: Oil analysis to determine actual change interval

Oil Selection:

  • Use manufacturer-specified oil grade
  • Consider operating temperature range
  • Fire-resistant fluids for high-temperature areas
  • Biodegradable oils for sensitive environments

Oil Analysis Parameters:

  • Viscosity: Should be within ±10% of new oil
  • Particle count: ISO cleanliness code
  • Water content: Should be < 0.1%
  • Acid number: Indicates oxidation

Filter Maintenance

Filters remove contamination that causes component wear. Regular filter replacement is essential.

Filter Change Schedule:

  • Return line filters: Every 500-1000 hours
  • Pressure filters: Every 250-500 hours
  • Suction strainers: Clean monthly
  • Breather filters: Every 1000 hours or annually

Change Indicator:

  • Most systems have visual or electrical change indicators
  • Replace filter when indicator shows change needed
  • Never bypass or remove filters
Hydraulic System Maintenance

Hydraulic System Maintenance Guide

Leak Detection and Repair

Hydraulic leaks waste energy, create safety hazards and cause environmental concerns.

Common Leak Points:

  • Cylinder rod seals
  • 泵 and motor shaft seals
  • Quick couplers
  • hose fittings
  • Filter housings
  • Connection fittings

Repair Approach:

  • Tighten fitting if leak is minor
  • Replace seals on cylinders and motors
  • Replace damaged hoses before they fail
  • Use proper fittings and torque specifications

Troubleshooting Common Problems

Low Pressure:

  • Check oil level — add oil if low
  • Replace clogged filter
  • Check for internal pump leakage
  • Verify relief valve setting
  • Inspect for cylinder leakage

Erratic Operation:

  • Air in system — bleed and check for leaks
  • Low oil level — fill and check for leaks
  • Dirty or worn valves — clean or replace
  • Collapsed hose — replace

Excessive Heat:

  • Check oil cooler is clean and functioning
  • Verify fan or pump is operating
  • Low oil level — fill and check for leaks
  • System overworked — reduce load or add cooling

Noise:

  • Pump cavitation: Check suction side
  • Worn pump or motor: Inspect and replace
  • Air in system: Bleed and check for leaks
  • Loose components: Tighten and secure

WSHT provides hydraulic system maintenance support including oil analysis, filter replacement and hydraulic component repair services.

Written by

WSHT Mining Group

WSHT Mining Editorial Team consists of senior mining engineers, metallurgical experts and industry analysts with 15+ years of on-site experience in crushing, screening, grinding and flotation circuits worldwide.

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