Why Does A Hydraulic Cylinder Leak And How To Repair

In the daily use of hydraulic cylinders, we often encounter oil leakage which has brought a lot of trouble to the user, so why does the hydraulic cylinder leak oil? What should we do on hydraulic cylinder repair? This article will discuss this problem and its solution.

Under normal circumstances, there are two types of oil leakage in hydraulic cylinders. That is external oil leakage and internal oil leakage.

Three reasons for internal oil leakage.

  1. The wear ring on the piston is severely worn, causing friction between the piston and the cylinder barrel, and finally straining the cylinder barrel, piston and seal.
  2. The seal fails for a long time, and the piston seal (mostly U, V, Y ring, etc.) is aging.
  3. The hydraulic oil is dirty, and a large amount of impurities enter the hydraulic cylinder to wear the piston seal to a bad condition, usually iron filings or other foreign objects.

What to do for hydraulic cylinder repair?

  • Maintain the cleaning of the operating environment of the hydraulic cylinder, and often remove the mud and sediment on the hydraulic cylinder of the equipment.
  • Remove the residue from the reducer and motor.
  • Maintain the excellent heat pipe heat dissipation of the hydraulic transmission system and natural ventilation.
  • Avoid high temperature of hydraulic oill.
  • The repeated movement of the hydraulic oil will have a certain impact on the sealing performance, so after a long time of application, we should remove and replace the seal early at a moderate time, and the season is in the summer or the beginning of winter.

Seven reasons for external oil leakage.

  1. The damage to the seal between the protruding end of the piston rod and the piston rod that is mostly caused by the roughening of the piston cylinder or aging.
  2. The damage to the seal between the extension end of the piston rod and the cylinder barrel. That is mostly because of the aging of the seal after long-term use, or many of the seals are damaged by excessive force on the cylinder end cover, or the hydraulic cylinder manufacturer’s unreasonable design.
  3. Cracking of the hydraulic cylinder inlet and outlet pipe joints can also cause leakage of the hydraulic cylinder.
  4. Defects on the cylinder barrel or cylinder end cover will also cause oil leakage.
  5. The piston rod is strained and has grooves, pits, etc.
  6. The deterioration of lubricating oil makes the temperature of the hydraulic cylinder rise abnormally, which promotes the aging of the sealing ring.
  7. Exceeding the pressure range of the hydraulic cylinder in application might cause oil leakage.

How to solve it?

  • Reasonable design of the hydraulic cylinder to avoid the subsequent oil leakage problems.
  • Replace the damaged cylinder components or parts when it is badly damaged and cannot be used.
  • For some large equipment, the cost to replace the hydraulic cylinder parts especially the piston rods and cylinder barrels is quite high. Hence how to maximize the service life through repair has become a problem worthy of attention. The piston rods repair methods have been introduced in another article “How To Repair Chrome Plating On Piston Rods“. 
  • To find a reliable factory to repair the damaged cylinder parts when you can’t repair by yourself. JW HYDRAULIC supplies this service. Once you have troubles about damaged hydraulic cylinders or parts, just pack them properly, and leave all other transportation, inspection, maintenance and other matters to JW. All hydraulic cylinders or cylinder components will be to well repaired and shipped to you within the agreed time frame.

Hydraulic Cylinder Parts Repairing Gallery


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