Well maintained springs can last a very long time, but after so much stress and constant usage, there may come a time when you need to replace them in order to maintain the necessary levels of performance. Obviously, if a spring cracks or breaks, it’s time for a replacement, but ideally things won’t get this far. If you pay attention to the springs, you can ensure less downtime from breakages by spotting any problems before they get out of hand.
As custom spring manufacturers will tell you, one of the most common factors that cause springs to fail is fatigue. There doesn’t have to be any significant faults in the spring. It is simply a consequence of constant and repeated stress. Eventually, a fatigue crack can appear in any type of spring, whether it’s a custom extension, torsion, leaf or spiral. These fatigue problems can occur in any size spring, as well, so even if your materials are over 50mm thick, you should still check to see if it’s time for a replacement.
Spring fatigue can start with just a micro-fracture which will continue to grow every time it is used. Extreme temperatures or corrosion can also affect the fatigue strength of the spring until it eventually hits the breaking point. If you take a few precautions, though, you can replace these springs before they ever reach that point.
There are a few ways to determine whether or not your springs are still performing as well as they should. Depending on the application, there are some simple things that will immediately tell you if it’s time for a replacement.
For example, stainless steel compression springs in a vehicle are meant to support its weight, not deal with the bouncing. The shocks and struts are supposed to handle that and provide a smooth ride. If those components have gone weak, though, the springs will have to deal with a lot more weight and added stress. If this is the case, you will likely start to notice some clunking noises or other unpleasant sounds as the coils weaken. The signs will be clear. You just have to be aware of what’s happening around you.
In other instances, you may be able to look at the way the platform or chassis is sagging. This is generally the most common way to inspect a spring, but it requires that you actually measure the distance between the ground and the platform since you might be wrong if you just eyeball it.
You can, of course, inspect the springs closer up. Simply run your hands all the way around the coils from front to back, top to bottom. Keep in mind that many coils have a protective layer that might conceal a fracture, but if you are careful and work slowly, you should be able to feel any problems. This method can help you find any stress cracks, missing coils, or questionable areas between coils.
Just remember that there really is not a standard life expectancy for springs. It all depends on a range of factors, from the temperature of the surrounding environment to the regularity of the stress. If you’re really in doubt, consider calling in a trained professional for a second opinion.