Whether it’s a fender bender, pushing the limits off-road, or a serious collision, your chassis can be damaged, twisted, or bent, affecting all of the systems that are attached to it. Damage to the framework of your car will likely be noticeable, whether it results in an inability to steer properly, your vehicle’s alignment being off, or noise when turning or driving over bumps. Our helpful list below can help you better understand the symptoms of a damaged chassis or suspension parts so you can begin your diagnosis and repair or replace the failing parts.
Similar to the skeleton in the human body, your vehicle’s chassis is the metal framework that helps link and support mechanical components, including the engine, brakes, power steering, tires, and more. Designed to add structure, the chassis is a crucial component to your car’s stability and durability. It links important parts to your vehicle and its frame to help it perform exactly how it should on the road. Every single component on your car is based on the chassis’ structural foundation and support, making the chassis a critical part of your vehicle’s overall performance and safety. Over time, your chassis, suspension, and other components can be damaged or bent due to severe use or collision, or may need general maintenance due to normal wear and tear. A damaged chassis or failing suspension components can cause a variety of symptoms, from uneven tire wear and poor handling to underperforming shocks and struts, and an uncomfortable or unsafe ride. If you think your car’s chassis or suspension is damaged, it’s first important to understand the way the chassis and suspension work together and what each of the components in the system does.
What’s The Difference Between a Chassis and Frame?
If you’ve wondered if your car’s frame and chassis are the same thing, the short answer is “no”. Although the meaning of “chassis” translates to “frame” in French, there are a few characteristics that make these parts different. The frame is a larger metal structure that helps attach the chassis, which links individual components for a variety of engine and suspension components. A frame is made to fit the body of your vehicle and acts as its primary structure, while your chassis and suspension components are connected to the frame and provide the connection point for mechanical parts like axle assemblies, tires, steering, braking systems, and the engine itself. Despite some use of the terms interchangeably, there is a difference in the structure and purpose of a chassis versus a frame.
Explaining The Two Types of Car Chassis
Vehicles on the road today have one of two chassis types: a body-on-frame chassis or a unibody chassis. Made using different materials and attachment styles for mechanical components, the two types of chassis are meant to supply the proper support and framework depending on a vehicle’s body style and build. View the helpful table below to learn about the differences between body-on-frame chassis and unibody configurations.
| Chassis Type | Body-On-Frame Chassis | Unibody Chassis |
| Design | Made of square steel tubing that is welded together to create a solid framework similar to a ladder. This configuration is more durable and able to support heavy car parts. The body of a vehicle rests on the chassis, and vehicles can have a front and rear chassis depending on their design. | Made of stamped metal sheets with mechanical parts attached by welds, bolts, glue, and screws. The body of the vehicle and the chassis are connected to the frame. |
| Common Uses | Used on nearly all pickup trucks, heavy-duty SUVs, commercial vehicles, and classic cars. | Used on most modern cars, sedans, crossovers, and lightweight SUVs. |
Why Do Chassis or Suspension Parts Fail?
Whether your chassis becomes twisted or bent from a collision or wears out from constant use and heat exposure, a damaged chassis or worn suspension components are good reasons for a proper inspection. A forceful impact with another car or object, as well as offroading, can obviously cause damage to the exterior of your vehicle. However, it should be considered that hidden or less visible components, like your chassis and suspension parts, can also sustain similar damage. Even if the exterior parts of your vehicle may not have sustained damage, a car crash, collision, or off-roading activities can cause significant damage to the metal linkages, suspension parts, and welded material that makes up your chassis and suspension system.
It’s also possible that chassis and suspension components can wear out over time due to heat exposure, stress, and constant use, and in areas with a lot of road salt or in off-road vehicles, these parts may also succumb to rust. Your vehicle may also be more susceptible to chassis damage if you live in a high-moisture environment or near the coast, since this added moisture can cause a more rapid development of rust. The failure of parts like sway bars and links, control arms, sway bars, tie rod ends, and leaf spring shackles can prevent your vehicle from driving smoothly and quietly. All suspension parts are considered wear items that will need to be replaced throughout the vehicle’s life, even if your vehicle has not been involved in a wreck. Greasing suspension components that have zerk fittings can help prolong their life, but many suspension parts on modern vehicles are pre-greased when they are manufactured and are non-serviceable.
Springs
All modern vehicles have some type of springs integrated into their suspension system that are designed to keep wheels in contact with the ground. Springs are also engineered to absorb the motion of the suspension system, and work with the shocks or struts to deliver a smoother ride. Springs and shock absorbers can help absorb any load changes or shock from uneven terrain so that these conditions don’t affect your driving comfort or safety. There are four types of springs that may be seen on a vehicle, including air springs, coil springs, leaf springs, and torsion bars, and in vehicles equipped with struts, the spring may be integral to the strut assembly. A vehicle’s springs are made to support specific loads and have specialized purposes, depending on the type of vehicle, for ideal performance and comfort.
Signs of Bad Springs Include:
- Excessive tire wear
- Severe rust or corrosion seen on springs
- Sagging vehicle on one or both ends or sides
- Lower ride height or poor tire clearance
- Vehicle wanders on the road
Shock Absorbers & Struts
Another one of the motion-damping components on your vehicle are shock absorbers and strut assemblies. These parts contain hydraulic fluid or pressurized air, and your car’s shocks or struts are made to work in conjunction with the springs to more effectively absorb and dampen road shock. A vehicle’s shock or strut configuration is unique to each car and their driving capabilities or purpose, and it’s important to remember how shocks and struts are different. Some vehicles feature shocks on both the front and the back, while others have front struts and rear shocks for better structural reinforcement. Some vehicles even have struts on all four corners, and these vehicles are typically designed for maximum performance and handling. Due to constant stress and environmental exposure, your shocks and struts will wear out over time, and may wear more rapidly depending on your driving habits and terrain. Damaged ride control components, including shocks and struts, may not only cause an uncomfortable ride, but can also be dangerous as they can decrease handling and increase braking distance.
Signs of Bad Shocks Include:
- Diminished ride comfort
- Bouncing on rough or bumpy terrain
- Nose-diving or squatting during acceleration or braking
- Longer braking distance
- Fluid leaking near the shock absorbers
Signs of Bad Struts Include:
- Diminished ride comfort
- Bouncing on rough or bumpy terrain
- Nose-diving or squatting during acceleration or braking
- Longer braking distance
- Fluid leaking near the struts
- Torn strut bellows
- Vibrations at the wheel end
Tie Rods
A vehicle’s tie rods are a structural component that helps align your vehicle and help steering components move in sync with your suspension. Most vehicles are designed with an inner and outer tie rod, with the inner tie rod attached to the steering rack and the outer tie rod connected to the steering knuckle. These components are threaded together in the middle to allow them to be adjusted to set the alignment. Factors like normal exposure and deterioration, harsh road conditions such as potholes, and a lack of lubrication can cause damage and allow your tie rod to become loose. When this happens, the tie rod or tie rods will need to be replaced to prevent damage to the tires or poor handling.
Symptoms of Tie Rod Failure Include:
- Wandering vehicle
- Clunking noises during turns or on bumpy roads
- Cupping wear on tires
- Poor alignment and imprecise steering
- Damaged grease boot or loose tie rod joint
Ball Joints
The ball joints on your vehicle are designed to allow wheels and suspension to move at a variety of angles and allow the steering knuckles to swivel to steer the vehicle. Designed as a ball with a threaded stud, socket, and rubber boot, ball joints are a key component to helping a vehicle’s wheels maintain contact with the ground, and the ball joints also allow for optimal suspension movement and articulation. Ball joints connect the steering knuckle and control arm, allowing the control arm to move up and down and change angles freely while keeping the tires in contact with the ground. A vehicle’s ball joints are not indestructible, and depending on driving habits, road terrain, and environmental conditions, you can expect to get around 70,000 miles before noticing signs of ball joint failure.
Symptoms Of A Bad Ball Joints Include:
- Knocking or clunking sound when turning or going over bumps
- Damaged ball joint boot
- Loose or wandering steering
- Vibrations at the wheel end
- Premature tire wear
Sway Bars & Sway Bar Linkage
Sway bars and sway bar links act as a tether to connect both sides of a car’s suspension, ensuring a more balanced, stable vehicle when making turns and cornering. Sway bars connect the control arms to the frame, which results in more flexible and controlled suspension movement and allows for optimal contact between the wheels and the ground. The sway bar links are meant to connect the sway bar and control arm and include bushings that can wear out with time and may require replacement. The sway bars and sway bar links are likely to require replacement at some point in a car’s lifetime since they are exposed to harsh road conditions, heat, and constant stress that can cause rust, wear, and eventual failure.
Signs of Bad Sway Bar Components Include:
- Swaying when making high-speed turns
- Clunking sounds when going over bumps or making low-speed turns
- Visible damage to the sway bar bushings or dust boots
Control Arms & Bushings
A vehicle’s control arms are often shaped like the letter “A”, which is why they are commonly called “A arms”. The control arms help the wheels maintain constant contact with the road, and allow the tires to move up and down as needed when driving over bumps or uneven terrain. Control arms function similarly to a hinge, which helps tires move vertically when driving, while the bushings connect the control arms to the frame to keep them tight and minimize noise. Control arms help to link the chassis and knuckle using ball joints to support the wheel end and allow for optimum suspension articulation. Control arms and control arm bushings are susceptible to corrosion, wear, and eventual failure depending on your driving environment and habits. In some newer vehicles, the ball joints are integrated into the control arm, and if either component requires replacement, the entire control arm and ball joint assembly will need to be replaced. The configuration of your vehicle’s control arms can vary, and it may feature a multi-arm system, just a lower control arm, or both upper and lower arms, so it’s important to understand your car’s control arm and suspension design before performing any repairs.
Signs Of A Bad Control Arm or Bushing Include:
- Clunking or groaning noises when braking or turning
- Poor alignment or excessive wheel camber
- Vehicle wanders on the road
- Cupping wear on tires
- Excessive vibrations
Steering Knuckle/Spindle
The steering knuckle and spindle are an articulating steering component that allows the wheels to be controlled by the steering system. The knuckle not only connects the upper and lower control arms, but may also include the hub assembly that allows the wheel to spin. In vehicles equipped with spindles instead of knuckles, there is a built-in shaft that connects to the hub and uses wheel bearings to keep the wheels turning. Steering knuckles and spindles are also connected to the tie rods to permit the wheels to be turned. The steering knuckles on your vehicle don’t usually wear out or suffer any damage unless your car has been in a collision or hit a large pothole, which can break or damage the knuckle. A bad steering knuckle or spindle can put you and others in danger, and can cause a lack of control over your vehicle when driving and steering. Not only can a damaged knuckle or spindle make driving more complicated and dangerous, but it may also cause additional stress to other suspension components, which can result in further damage and reduce overall vehicle handling and safety.
Signs of a Bad Steering Knuckle or Spindle Include:
- Poor alignment
- Uneven tire wear
- Poor handling
- A tilted front wheel
- Squealing noise when making turns
- Steering wheel is misaligned when driving straight
Since suspension and chassis components are so closely intertwined, signs of bad suspension parts can include odd noises, tire wear, alignment issues, and more. Because these symptoms can affect multiple systems, it’s important to inspect these components individually to help determine the source of your suspension problems. We’ve compiled a list of the most common suspension symptoms to help you better understand the reasons many of these signs of failure are common amongst your suspension system and chassis.
How to Repair Chassis and Frame Damage
If you suspect your chassis is damaged, or if it has been bent or broken in an accident, the vehicle should not be driven until the damage can be assessed by a professional mechanic and addressed. Chassis and frame repairs are not a DIY task, and failing to have your vehicle repaired professionally after an accident could cause poor alignment and suspension problems. This is a repair that should be done in a timely manner, since avoiding this task can cause issues with your tires, steering, ride control, and more. The only way to be sure that your vehicle’s chassis is not damaged beyond repair after an accident is to have it professionally evaluated and repaired.
Even if you haven’t been involved in an accident, suspension repairs can be a daunting task and may be difficult to diagnose and pinpoint. If you don’t feel confident inspecting your chassis or suspension or performing these repairs, our parts professionals have compiled a list of professional automotive shops near you to help get your vehicle safely back on the road and driving as it should.
O’Reilly Auto Parts Stocks The Chassis Parts You Need
Whether you need jack stands for a safe chassis inspection, easy undercarriage access with a creeper, or if you want to browse our selection of chassis parts and tools, O’Reilly Auto Parts has you covered. We carry replacement ball joints, control arms, drag links, and much more. If you’re inspecting your vehicle or performing chassis or suspension repairs, check out our How-To Hub for helpful step-by-step videos on topics like routine automotive maintenance intervals, how to safely jack up your vehicle, how to replace a sway bar link, and much more. Find the parts you need at O’Reilly Auto Parts, where you can shop online or at an O’Reilly store near you to find the right components, equipment, and tools to get the job done right the first time.