O-rings are most commonly used with hydraulic systems, but they are also used with other types of machinery and equipment, and they're even used with swimming pool components, firearms and more. If you're purchasing O-rings to use with your hydraulic system or for any other purpose, these are the main things you'll want to pay attention to when you're choosing your O-rings.

Temperature Ranges

First of all, you should think about the temperature ranges that your O-rings will probably be exposed to once they are installed. Typically, hydraulic equipment can range in temperature from low to high temperatures at various times throughout the day. Therefore, you will need to be sure that your O-rings can handle being exposed to both the lowest and highest temperatures without being damaged. Additionally, remember that they probably will not be exposed to these high and low temperatures for brief or occasional periods. Instead, if you use your equipment regularly, there is a good chance that your equipment will be exposed to both these high and low temperatures on a regular basis, including for sustained periods of time. Luckily, O-rings are typically rated for different temperature ranges, and this is not something you should ignore when you're shopping for them. Instead, you should find out about the temperatures that your equipment will expose your O-rings to — such as by checking the manufacturer information for your equipment — and ensure that the O-rings that you purchase are designed to be exposed to these temperatures.

Material

You'll need to pay attention to whether O-rings are made from rubber, thermoplastics or other materials. O-rings made from different materials have their own pros and cons for you to consider.

Hardness Or Rigidity

Some O-rings are much more flexible than others, which can make installation easier. However, this can increase the chances of the O-ring breaking or snapping during installation or otherwise. You should consider these things and choose an O-ring that is properly rigid for your needs.

Resistance Against Chemicals

Next, you should know that your O-rings will likely be exposed to various gases and liquids, including chemicals like hydraulic fluid. Not all O-rings are designed to be exposed to these substances and can be damaged in the process if they are exposed. The right type of O-ring should be able to withstand this type of exposure, however.

Sizing

O-rings are measured with either standard or metric measurements depending on the equipment that they are being installed on. You should make sure that you're using the right measuring system and the right measurements when shopping for O-rings. This ensures easy installation and a proper seal.