According to Mining and Hydraulic Supplies, the successful use of O-Rings depends upon many factors:
Surface Finish – All metal surfaces over which the O-Rings move should be held to a maximum finish of 16RMS, although the groove finish can have a maximum of 32RMS. There should be no nicks, burrs, or scratches.
Metals – All metals over which O-Rings move should have a hard surface such as steel, nickel-plated, or chrome-plated. Special attention should be given if you select soft metals such as aluminium, brass or bronze.
Excessive Metal Clearance – Clearances should be held to the recommended maximum diametrical tolerance. Consideration must be given to the breathing of cylinder in your calculations – which is the possibility of the cylinder bore to expand or balloon out at its centre.
Concentricity – It is important to hold eccentricity within the recommended practice and to design for sufficient bearing area to take care of side loads or off centre loading.
Cleanliness – All systems should be kept clean and free from dirt, grit, chips and any foreign materials. Any type of abrasive material will cut the O-Rings. When replacing failed O-Rings, look for tiny metal chips embedded into the O-Rings which could mean a pump problem.
Squeeze (preload) – For good sealing, the minimum diametrical squeeze should be observed. Where pressures are low and friction is critical, the amount of squeeze can be decreased but caution should be exercised.
Lubrication – When used in pneumatic systems, O-Rings should be lubricated. If permitted to run dry, then they will face abrasion and twisting.
Groove Design – Proper design is a most essential factor in the successful operation of O-Rings. The rectangular shaped groove is recommended except for special applications.