Subframe Bushing Buyer's Guide
- Subframe bushings are one of the many types of automotive bushings. They help hold components that are connected to the subframe.
- These anti-vibration mountings are able to keep linked parts isolated, preventing the surfaces in the attachment points from directly touching and rubbing against each other, dampening friction, vibration, noise, and harshness.
- There are many different types of bushings depending on design, material, and application.
- Although there is no recommended replacement interval for subframe bushings, some signs that may indicate when these should be changed include loud noises, steering problems, unusual tire wear, alignment issues, and strange movements.
- Subframe bushing replacement costs will depend on factors such as brand, mounting location, quantity, and service fees. The bushings themselves cost from around $25 to $316 at CarParts.com. They can be bought individually or in sets and kits.
Vehicles are subject to numerous loads and forces that can sometimes oppose each other. Causes of stress include the vehicle’s weight, road impact, friction, inertia, and air resistance. Vehicles are built with rigid frames and body panels to help them withstand these loads and forces. The frame serves as the skeleton that provides structural support to the bodyshell and holds many of the vehicle's components.
The subframe is a distinct structural component of the vehicle and can be located on both the front and rear of the vehicle or on a single end. It’s usually made of metal that is formed into square or round tubes. This structural element helps distribute the load of the chassis as well as reinforce the vehicle and support other parts. The subframe can hold or support certain components that can include parts of the powertrain or the suspension system. It can also isolate the vibrations generated from operating the vehicle or coming from the car's mechanical parts.
What Are Subframe Bushings?
The subframe can either be welded or bolted on, depending on the design and construction of the vehicle. When it’s bolted on, it can contain bushings or springs that help in dampening vibrations.
Bushings are a type of plain bearing used in vehicles and other machines that feature sliding or rotating parts. They’re located between moving components, providing an interface and cushion for these parts and serving as anti-vibration or flexible mountings.
Subframe bushings are among the numerous bushings that are made or designed according to their use and application. They help hold the components that are connected to the subframe. The design and configuration of the subframe determines how many bushings it can have. Subframes can have anywhere from two to more than eight bushings.
What Do Subframe Bushings Do?
Driving creates vibrations that can travel through the vehicle. Causes of vibration include the spinning wheels’ contact with the road and engine pistons’ movement. In addition to jarring movement, vibrations transmitted through the vehicle can also create noise. The ride can become uncomfortable if the vibrations get to the cabin.
Car makers use bushings to address noise, vibration, and harshness to meet standards and ensure customer satisfaction. Anti-vibration mountings such as subframe bushings are able to keep joined parts isolated. This prevents surfaces in the attachment points from directly touching and rubbing against each other while the connected parts move. Bushings also serve as padding for the joints,allowing the linked components to move while dampening friction, vibration, noise, and harshness.
Subframe Bushing Material and Construction
Bushings vary according to design, material, and application. Bushings are typically hollow cylinders of rubber or polyurethane. They can feature an internal crush tube and outer casing that can be made of metal. Automotive bushings can also be filled with liquid.
This type of bushing can dampen vibrations and noise well due to the flexibility of its material. However, its flexibility makes it susceptible to having air gaps, resulting in deflection and causing wheel hops during hard acceleration. Rubber bushings are also more likely to warp and tear. Combining rubber bushings with other material will change their characteristics.
- Adding another layer of rubber to this bushing makes it harder and more durable. On the other hand, it will aslo transfer more vibration and noise to the cabin.
- Hydro bushings are liquid-filled rubber bushings that can dampen vibration and noise better than plain ones. They are often used in luxury vehicles due to these attributes. Although they meet the durability standards set by original equipment manufacturers or auto makers, hydro bushings can develop leaks or dry out. Withered hydro bushings can easily tear or crack.
Made of rigid plastic, polyurethane bushings are sturdier than their rubber counterpart. They’re stiff and don’t deflect due to air gaps. This makes them ideal for performance driving or situations that require less movement between the car's structural parts. Polyurethane bushings have more structure because of a metal tube in their middle, which prevents parts from cutting into the bushing. However, these bushings transmit more vibration and noise due to their stiffness. Poorly lubricated polyurethane bushings can also squeak.
Harder bushings are also available on the market. They’re made of metal and are much more resistant to wear. This type of bushing provides better road feel than less rigid bushings and highly minimizes body roll. However, they aren’t recommended for road cars as they greatly transfer vibration and noise.
Subframe Bushings Symptoms
Subframe bushings withstand loads that can cause them to wear out over time. Exposure to extreme heat and cold, salt, oil, and other elements can also cause subframe bushings to fail. Worn or damaged bushings should be replaced. Although there’s no recommended replacement interval for subframe bushings, below are some signs that could indicate when these should be changed.
Without properly working bushings to dampen it, road noise will easily be transmitted to the cabin. Other subframe bushing noises like clunking, creaking, and rattling can occur while turning and when driving over rough and bumpy roads.
Degraded subframe bushings can lead to loose steering wheel movement or make it feel harder or softer while turning. The steering wheel can become unresponsive, making it difficult to drive straight and control the vehicle. Braking might also feel different.
Uneven Tire Wear
Changes in steering behavior due to bad bushings can cause the tires to wear out unevenly.
Deformed bushings can cause the subframe to become misaligned. This could affect the position of connected parts, such as the steering and suspension components. The phenomenon can also cause wheel camber, caster, and toe to change.
Worn subframe bushings will cause unusual and excess movement in the subframe. Handling can feel loose. More vibration can also be transmitted into the cabin.
Subframe Bushing Replacement
Old subframe bushings can disintegrate completely if left alone. Replace bad subframe bushings as soon as possible to prevent vehicular problems.
To ensure a good fit it’s important to take note of your vehicle's make, model, and year when getting replacements for your subframe bushings This vehicle part is designed based on the component it’s mounted on, and will have a corresponding position.
Subframe bushing replacement costs will depend on factors such as brand, mounting location, quantity, and service fees. Bushings can cost from around $25 to $316 at CarParts.com. They can be bought individually or in sets and kits.