Proper lubrication is essential when installing hydraulic seals. Not only does it make assembly easier, but it also helps protect seals from premature wear, overheating, and damage that can shorten the life of your hydraulic cylinder.
Why Lubrication Matters
When seals are fitted without the right lubrication, they experience increased friction as components move against each other. This can lead to excess heat, accelerated wear, and ultimately, seal failure. Using the correct lubricant reduces these risks while ensuring smooth installation, whether you’re sliding a piston seal down the bore or guiding a shaft through the gland.
Equally important is choosing a lubricant that won’t damage the sealing material or contaminate the hydraulic system.
Recommended Lubricant
The best option is hydraulic oil, specifically, the same clean, uncontaminated oil that will be used in the cylinder during operation.
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Always check that the oil is free from dirt and debris.
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If your system oil is dirty or degraded, replace it with fresh, clean oil before using it for installation.
By doing so, you not only protect the seals but also extend the service life of the entire cylinder.
What to Avoid
Certain substances can harm seals or compromise your hydraulic system. Avoid the following:
Greases and Petroleum Jellies
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Petroleum-based, silicone-based, lithium-based, and copper-based greases (including Vaseline) can degrade polyurethane, rubber seals, and composite guide rings.
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Grease can clump, circulate through the system, and cause valve blockages.
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It may also trap air inside seal housings, leading to air damage or “dieseling” once the cylinder is in service.
Non-Hydraulic Oils
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Motor oil, differential oil, power steering fluid, brake fluid, and even cooking oils are not suitable.
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These can soften and swell seals, leading to catastrophic failure.
Sprays and Solvents
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Aerosol sprays (e.g., WD-40, CRC, lanolin sprays) contain additives that break down seal materials.
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These products should never be used as assembly lubricants.
Key Takeaway
Always use the correct hydraulic oil during seal installation. It ensures compatibility with the seals, protects the hydraulic system from contamination, and guarantees smoother, longer-lasting operation of your hydraulic cylinder.
