Why Rubber Seals Leak: Causes of Failure
A rubber seal is installed to provide a tight seal, but over time or due to a wrong choice it can start to leak. Understanding the cause of the leak prevents repeated failure. Below we review the most common causes.
1. Wrong material selection
The most common cause is making the seal from a material unsuited to its working environment. For example, an EPDM seal will swell in an oil environment, while NBR will harden in a hot-steam environment. The material must match the contact medium, temperature and pressure. Our seal selection guide will help you choose correctly.
2. Over- or under-compression
A seal works with the correct compression. If over-compressed, the rubber takes a permanent set and loses elasticity. If under-compressed, the required tightness is not achieved and fluid passes through. The compression rate recommended by the manufacturer should be observed for each seal.
3. Ageing and chemical degradation
Rubber ages over time. UV, ozone, heat and chemicals harden the material, cause cracks and reduce elasticity. For seals working outdoors, ozone- and UV-resistant EPDM should be chosen. Where high temperature is required, Viton (FKM) lasts longer.
4. Installation errors
- Cutting the seal as it passes over threads or sharp edges.
- Tearing during installation without lubrication.
- The seal not seating correctly in the groove or twisting.
- Loss of surface cleanliness — dust or debris break the seal.
5. Wrong hardness (Shore)
A too-soft seal can extrude out of the groove under high pressure, while a too-hard seal may not seat fully against the surface. A hardness suited to the application matters; our article what is Shore hardness will help here.
6. Mechanical wear and vibration
In moving joints, constant friction and vibration wear the seal. Such cases require wear-resistant compounds and a correct design.
How to prevent leaks
The right material, the right hardness, accurate dimensions and careful installation prevent leaks. In doubtful cases, sharing the environment and operating conditions with the manufacturer gives the best result.
At NUR KAUÇUK we produce durable seals for your application. Review our products or contact us for technical support.