Hydraulic Cylinder Seals

Guidelines for Optimum Performance of Hydraulic Cylinder Seals

wiperThe following basic yet important facts regarding the use of hydraulic cylinder seals will, if followed improve performance and reduce downtime.

  1. Excessive Clearances – between the piston and cylinder wall the seal will be subjected to deformation causing extrusion. The pressure will cause the seal to fail.

Prevention: Use the recommended clearances and accurate assembly to ensure that the clearance is equal all around.

  1. Scored rods and/or cylinder walls – Severe scoring prevents the seal lips from sealing the entire surface resulting in leakage. The deeper the score marks the less positive the sealing plus reducing the life of the seal. and

Solution – Refinish rods and/or cylinder walls.

  1. Foreign matter, dirt, metal shavings etc. – in the hydraulic system will cause many problems with seals. Seepage and premature failure can occur along with damage to equipment.

Solution – Proper installation, preventative maintenance and filtration.

  1. Damage to sealing lips – It is imperative to ensure that care be taken when installing the seals. The use of sharp tools must be avoided.

Recommendation – Seals may be lubricated with a compatible medium to facilitate installation

  1. Fluid Temperature – Excessively high temperature can cause a seal to lose memory which will result in the fluid leakage.

Solution – the correct sealing material should be used to prevent seal failure

  1. Chemicals – incorrect analysis of chemicals/fluids used as hydraulic medium will attack the seal and cause failure.

Solution – Analysis of the hydraulic medium matched with proper seal compound

  1. Excessive wear – usually indicates that the seal has not been properly seated. This will result in a short service life.

Solution – Attention to proper seating and/or adjustment

  1. Wear on one side – could be due to worn/misaligned bearings, wear rings or rods that will result in excessive wear on one side of a seal.

Solution – Re-bushing and aligning the assembly to ensure proper guidance.

While many of these issues may be logical it is always relevant to remind ourselves of the basics. I trust this article will be of value.