- All
- Product Name
- Product Keyword
- Product Model
- Product Summary
- Product Description
- Multi Field Search
Views: 0 Author: Site Editor Publish Time: 2026-11-12 Origin: Site
The whole machine's seal rides on this one ring. This O ring, ID19 OD24 CS2.5, is the last line of the seal.
It is the smallest part and it carries the heaviest job. Every oil, water and gas line on a machine that must not weep has one O ring sitting in a groove. The ring rests in the groove, the two halves come together, the ring is squeezed, it fills the gap, and the leak is stopped. Lose this one ring and the most expensive part of the machine is wasted.
Why is the cord round? A round cord compresses and springs back. Squeeze it and it flattens to seal; let go and it returns to round. A flat washer stays flattened once compressed, but an O ring keeps its elasticity, which is why it lasts. Not forever, though; once it is squashed into a permanent set and will not rebound, it is done.
What is NBR? Nitrile butadiene rubber, the standard O ring material. It resists oil, fuel and heat, and it holds its spring. The black rings you meet are usually NBR. If the machine runs in a hot or chemical wash, check the material matches, but for general machine use NBR is the right call.
How are ID, OD and CS different? The ID is the inside, it must suit the groove's inner circle; the OD is the outside; the CS is the cord, the thickness of the ring, and it is the CS that must suit the groove depth. This ring is 19 inside, 24 outside, 2.5 cord, a standard size, and you can measure the groove and find it straight away.
How do you know it is done? Cracks, cuts, a ring that has hardened and will not compress, one that is flattened and will not rebound, or fuel weeping past the groove; that is the time to swap it. The O ring is the cheapest consumable on the machine, and replacing it in time keeps it from dragging the whole seal down.
How to fit it? Do not stretch it in, do not twist it, and do not let it pinch in the gap, a nipped ring will not seal. Slip a little assembly lube on the ring and the groove to help it seat, and once it is in, check that the ring sits in the groove without a twist.
