One of the most crucial components of your truck’s suspension system is the shock absorber. It plays many vital functions, including maintaining tire-to-road contact by controlling spring movement, protecting the truck’s springs and airbags, and reducing wear and tear to other suspension system components. Without properly functioning shocks, truckers are in for a bumpy ride, while fleet owners and commercial vehicle operators have to deal with increased operating expenses.

Generally, shock absorbers should be replaced every 150,000 miles on commercial vehicles. However, some trucks may need replacement sooner than later, especially those that often cruise in extreme weather conditions. And to know when is the best time to replace your truck’s shocks, here are some telltale signs that you should watch out for:

Fluid Leaking from the Unit

Shock absorbers are filled with oil, which is highly critical to their dampening ability, and they use a seal to ensure this won’t leak. While it’s normal to see a small amount of oil escaping around the seal, a shock that is covered in a heavy coating of oil or an oily patch on the ground indicates a more serious problem. And before you know it, the shock suddenly starts acting up, or worse, stops functioning altogether.

How to know if your truck has leaking shocks? Well, the most common signs are vehicle handling issues and uncomfortable and tiring rides. When you start experiencing any of these, have your shocks inspected by a professional mechanic because this means the shocks no longer control the oscillations of the chassis and suspension spring.

Upon inspection, your mechanic may tell you to replace the leaking shocks to prevent further damage to the other parts of the suspension system. However, take note that it's always best to replace them in pairs or all four. Replacing a single shock is highly discouraged because it can worsen your truck's handling characteristics.

Physical Damage

Aside from leaks, physical damage is another common visual clue that your shocks may need replacement. If you know your suspension components all too well, you can very much conduct a physical inspection yourself to determine this. If you notice visible wear and tear to the shock body or if it’s already dented, it’s time to consider getting a replacement.

You may also check for corrosion and any signs of damage to the bushings located at the end of either side of the shock absorber since these play a crucial role in your shock’s performance. When they start to corrode or wear out, they can no longer cushion the shock mounts from the suspension that they are attached to. As a result, your truck begins making a lot of annoying noises, especially when driving in rough conditions.

Lastly, be sure to inspect the seals for any cracks. Shock absorber leaks usually occur because of broken or damaged seals.

Uneven Tire Wear

When your truck's shocks are worn out, the truck can bounce, causing a reduction in road holding force. This excessive bouncing can lead to accelerated tire wear, including tread cupping or scalloping of the tires. Inspect your truck’s tires for unusual patterns and cupping on the tread because these often indicate a shock absorber issue that needs attention right away.

Poor Ride Quality

When your shock absorbers are loose, stuck, or damaged, the tires will not be able to make proper road contact, resulting in a bouncy and uncomfortable ride. Your truck’s steering wheel will also begin to shudder even if you are driving on a smooth road. And when you drive at high speeds, the steering wheel vibrations even become harder to control.

Worn shocks do affect the ride quality of most modern trucks. And if your truck is equipped with a taper leaf suspension or air suspension, you will notice the poor ride quality sooner than in a vehicle with full leaf springs. That is because this type of suspension system is softer, so if the rig you're driving has this, you can immediately feel the change in ride quality once the shocks get damaged.

Rattling or knocking sounds

Shock absorbers work by dampening vibrations through the bushings, which are used primarily to keep them in place. When these bushings become worn or get damaged, they produce knocking or rattling sounds. These sounds become more noticeable when you drive over bumps on the road.

Rattling or knocking sounds may also be due to a loose shock or one that has lost all of its oil and is rattling inside the shock body. And sometimes, they may not actually be from the shocks, so it pays to do a thorough inspection of your truck’s suspension system. Try checking the tie bar, ball joints, or sway bar. Damage to any of these parts can cause these unusual sounds, and when left ignored for a long time, they can lead to more serious issues, including total loss of steering control.

Now that you know all these signs, it’s a lot easier to decide when to get replacement shock absorbers. But before you make that purchase, do take note of the three most common reasons why shocks fail on commercial vehicles: cracked or split bushings, weak welding quality, and excessive oil loss. This will serve as your guide when shopping for OEM shock absorbers.

Find it at FinditParts: We have you covered when it comes to premium-quality replacement shock absorbers and other suspensions system components. We have a vast number of sources and enhanced visibility into the inventory of distributors and manufacturers of OEM and aftermarket brands, meaning you’re only a few clicks away from the parts you need. Need help? Our focus on service and support provides you with a repository of valuable information, customer facing technology including advanced cross reference capabilities, and technical specialists who assist in identifying and finding parts.