We don't spend a lot of time thinking about our rear suspension until the bed of the truck starts dragging on the ground. Worn leaf springs aren't always the culprit if the rear end starts to sag. There are bushings and springs in the rear end of every truck that need regular replacement to ensure the rear suspension works as efficiently as possible. What are rear suspension bushings and springs? How can you tell when you need to replace these components? Is this task something you can do on your own, or do you need the assistance of a professional?
What Are Suspension Bushings and Springs?
The rear suspension of your vehicle absorbs the vibrations that happen when you're driving down the road. Even smooth, well-paved roads generate vibration that could make your ride uncomfortable. The suspension system serves to absorb these vibrations, offering a smooth ride, but without suspension bushings, you might find yourself feeling every speedbump and pothole in the road.
Rear suspension bushings serve to isolate the truck's rear suspension system from the body of the car while keeping everything tightly aligned to prevent the suspension components from moving out of position. Each part of your suspension system, from the control arms and shock absorbers to the springs, sway bars and other components, relies on rubber bushings to ensure the smoothest ride possible.
These soft, polyurethane rubber pads keep the metal components in the suspension from knocking together while absorbing the road vibrations. You can find them throughout your vehicle, anywhere two pieces of metal come together.
Suspension springs, on the other hand, serve as a link between the wheels and the body of the car. They help compensate for uneven road surfaces while ensuring the wheels themselves are always in contact with the road. There are four types of suspension springs used in modern cars.
- Cylindrical suspension springs: These are the most conventional suspension springs and have a linear spring rate, meaning the spring force increases the more the rings squeeze together.
- Inconsistent wire suspension springs: These springs start with thinner wire at the top and get thicker at the bottom, which helps spread the compression load more equally.
- Mini-block springs: These barrel-shaped springs are made from tapered wire, which gives them a progressive spring rate.
- Banana-shaped side-load springs: These springs can control the force of the entire suspension system, which helps reduce the friction within the shock absorber.
The most common type of suspension spring is the coil spring, which sits around the shock or struts attached to each wheel hub and absorbs road vibrations.
How to Tell If Suspension Bushings Are Worn
How can you determine if it's time to replace the suspension bushings and springs in your truck's rear end? You may be asking yourself, "What problems do worn suspension bushings cause?" Are they merely noisy, or can they cause more significant problems? The symptoms of worn bushings and springs in the rear of your truck are more difficult to detect than problems in the front end. Drivers can detect a failure in the front-end suspension bushings because these failures tend to affect the steering of the vehicle, making it harder or even unsafe to drive.
In the rear, you may think your leaf springs are failing if it's time to replace your suspension bushings. You'll start feeling every bump in the road like you were riding over it on a bicycle. Bushings can fail over time, since their soft rubber material makes them prone to wear and dry rot. Once they do fail, the parts they were cushioning can rub or crash together, causing additional wear that could lead to premature failure.
Unlike other parts in the suspension system, there is no maintenance schedule to tell you when to change suspension bushings. You, or your mechanic, will also need to determine whether you can replace the failed bushing itself, or if you need to replace the corresponding piece of equipment because of premature wear and tear. Other than the symptoms we've listed, the only other way to tell if suspension bushings have become worn down is to lower the entire suspension system and inspect the bushings.
Suspension springs, also known as coil springs, can last the lifetime of your truck, but that isn't always the case. Over time, springs can lose their ability to bounce back. If the rear suspension springs start to fail, you may notice the rear end of your vehicle is bottoming out — scraping the pavement — when you hit a bump or when you are carrying a bed full of cargo. Worn springs can also contribute to steering problems, as the body of your truck may lean excessively during a turn.
Some common symptoms of failing coil springs include vehicle sag, uneven tire wear and noise emanating from the underside of the vehicle. It may also bounce more dramatically during driving or sway excessively as it moves. This extra movement will not only make your ride uncomfortable, but it could also make driving the truck dangerous. The way the truck moves will continue to become more abrupt and unstable, making it more difficult to control and potentially leading to accidents. These dramatic swaying motions can even cause the tires to lose traction because the suspension won't be able to keep the tires pressed to the road's surface with weak or sagging springs.
Uneven tire wear tends to be a subtle sign of coil spring problems. If the springs aren't holding the truck up correctly, it upsets the balance of the vehicle. The tires end up pressing to the road at odd angles, leading to uneven wear. If you're using your truck to haul heavy loads or spend a lot of time offroad, this uneven wear can make driving dangerous because the tires won't be able to grip the road or terrain properly.
Coil spring replacement becomes necessary when the springs are worn-out and sagging, but you might be able to put this repair off for a few weeks. If the spring breaks, however, you will need to replace it immediately. Do not try to drive a vehicle with a broken coil spring. If you don't replace the broken spring promptly and continue driving on it, it could ruin the axle, which will make the job much more expensive.
How to Install Bushings and Springs
You don't necessarily need to head to a mechanic to replace worn-out suspension bushings or springs. Here are our step-by-step instructions for saving yourself money by completing this task in your home garage.
How to Replace Suspension Bushings
Suspension bushing replacement can be a DIY project if you can set aside a good block of time and have the right tools available. The exact instructions might vary depending on the specific bushing that you're going to replace, but in general, you will need:
- A set of replacement bushings
- A set of open-ended wrenches
- At least one flathead screwdriver
- A torque wrench
- A floor jack and jack stands
- A vise or clamps
- A set of replacement suspension bushings
- Containers to catch gasoline or brake fluid, depending on the specific needs of your truck
Start by lowering the entire rear suspension assembly of the truck. If your truck has independent rear suspension, you can lower one side at a time. Start by jacking up the rear end of your truck and putting it on jack stands. Then, place your floor jack beneath the center beam and lift it just enough to support the suspension system without lifting the truck.
From there, you can disconnect the rear suspension. You might need to disconnect the rear brake lines to lower the suspension system — that's where those collection containers come in. If your truck has independent rear suspension, you'll be positioning your jack at the end of the control arm and lowering one side at a time. Once you're sure you have disconnected everything correctly, you can release the jack and lower the suspension system so you can access the bushings.
Now, you can remove the suspension bushing assembly from either side of the system. Each side will have at least one, but keep an eye out for additional bushings you might need to replace. Most have a single bolt and nut securing them in place, which is where your open-ended wrenches come in.
Once the assemblies are off, you'll need to press the bushing out of the center of each assembly. The easiest way to do this is to secure the assembly to your bench with a set of clamps and use a third clamp to slowly press the bushing out of the assembly. Depending on the state of the bushing, it may come out in pieces, so once it is clear of the assembly, take a moment to clean out the bushing's seat so there are no fragments of old bushing left behind.
Don't forget to lubricate the new bushing before you press it into the assembly. High-performance bushing kits may come with a tube of lubricant included. Assembling it without the lube will cause it to groan and squeak while you're driving, and can reduce the life of the new bushing. If the new bushing comes in two pieces, you may be able to press it into place with your hands, but if not, you can use the same technique with the C-clamp to press the new bushing into place.
From here, it's just putting everything back together in reverse. Reattach the bushing assemblies, lift and reattach the suspension and reconnect any brake or fuel lines you had to remove. If you had to disconnect the brake line, don't forget to bleed the brake system before you start driving the truck again to remove any air from the lines.
How to Replace Suspension Springs
Suspension spring replacement can be challenging because of the tension contained within these coiled pieces of steel. Start by collecting your tools, including:
- A combination wrench set with extensions
- A flathead screwdriver
- A pry bar
- A socket wrench set
- A work light
- Safety equipment
- A set of replacement suspension springs
Even if only one of your suspension springs is failing, you will want to replace both of the springs on the same axle to ensure the ride remains balanced. Many manufacturers also recommend replacing the shock or strut at the same time, but it's not required. Depending on your vehicle, you may also need a coil spring compressor to pre-compress the spring before you install it, and a ball joint if the ball joint ends up being in the way.
Before you do anything, disconnect the vehicle's battery — both the positive and negative terminals. Then, before you lift the car, figure out where the springs connect to the vehicle's strut assembly. Now, it's time to lift the vehicle and remove the wheel and tire. It's best to lift and work on one side at a time.
Next, you'll need to remove the bolts that attach the lower control arm to the wheel hub. Use your jack to support the control arm, pressing upward to lightly compress the spring. Then lower the jack until the spring is no longer compressed before raising it to support the control arm. This point is your zero-degree position where you will need to install your new spring. Now, remove the bolts and lower the control arm.
Once the control arm is out of the way, it will be easy to remove the spring. Then all you need to is install the new spring, using the jack to raise the control arm to that zero-degree position before bolting it back into place, torquing it to the manufacturer's recommended specifications. Finally, replace the rear tire and wheel, torquing the lug nuts to the recommended specs before lowering the truck and repeating the process on the other side of the axle.
Order Your Replacement Springs and Bushings From General Spring
If you've noticed your ride is getting bumpier or your truck is bouncing or swaying more than before, it's probably time to replace your suspension springs and bushings. The good news is that you don't need to take your truck to the shop. With the right tools and high-quality parts, you can repair your truck at home for a fraction of the cost of taking it to a mechanic.
Suspension springs and bushings are not all equal, and if you find you need to replace the ones currently on your pickup truck, you shouldn't settle for less than the best. For more than 50 years, General Spring has provided high-quality suspension components for truck lovers across the country, including suspension bushings and springs. Explore our catalog for all the replacement parts you could ever need to keep your truck driving smoothly for years to come, or contact us if you have any questions or can't find the perfect suspension bushings or springs to fit your make and model. General Spring has everything you need to make sure a failing suspension won't sideline your truck permanently.