When it comes to car maintenance, there are a few different categories that most people fixate on. Engine. Ok, that one’s easy, it makes a car go, and therefore there is value in keeping it well maintained. Brakes. Another easy one, very safety related and very easy to change. But chassis, the part that holds your car together, is often overlooked by even the most seasoned DIY’ers. Your chassis, however, is what makes a car FEEL right.
When a car feels old, sluggish, sloppy…that’s when you should understand that no amount of spark plug changes, air filter swaps, and brake jobs will make it feel like it used to. What you are feeling is the chassis itself getting tired. Every car is made up of a variety of large assemblies, and nearly every one has a rubber bushing to mount them in place, while simultaneously insulating the two parts from noise, vibration, and harshness (NVH). With a few more weeks left for us northerners to comfortably get tasks done before winter, bushings should be on your menu so you don’t have to slog through the winter months in a car that you don’t appreciate driving.
The eEuroparts Car Bushing Guide
For ease of reading, this will be part 1 of 2 for the eEuroparts Ultimate Bushing Guide. Part 1 will describe the bushings we feel you most need to think about when doing your big services. Part 2 will discuss the different brands we have to offer, to help you make the most educated choice when keeping your European car handling in tip top shape. There are three main bushing and mount groups to focus on when maintaining a car for the long run, each with a few subcategories.
Drivetrain to Subframe/Body
Engine Mounts
The engine and transmission is held to the car body or the subframe using a variety of styles of engine mounts, which contain large rubber bushings that degrade and cause excessive movement. There is an article here that goes into more detail. Older cars (Pre 1990ish) generally have most of their mounts straight to the body, where more modern cars have subframes where the control arms and engine mounts bolt on.
Driveshaft Flex Disc (Giubo)
On RWD and AWD cars, you also have a number of separate bushings involved. One in particular to be aware of is the driveshaft flex disc, also known as a Giubo (pronounced joobow not gweebo as many do, it’s a contraction of the inventor’s name, Giunti Boschi). This dampens torque and harshness along the rotational axis of the driveshaft, keeping it happy and increasing longevity of the various joints and bearings on each end. When worn out, it can cause hard
Driveshaft Center Support
Usually formed together as a single piece with a bearing, the center support is a mount that limits lateral movement in the driveshaft. When this bushing wears out, it can help cause an engine speed dependent vibration. We recommend changing this out with the bearing at the same time if they are not integrated.
Differential Mount Bushings
The rear differential in RWD and AWD cars is responsible for both the final gearing of a car (generally) and also directing power from the engine to the wheels. Because the power is taking a 90deg turn, there is considerable motion to wrangle in, and that comes down to the differential mount bushings. Good condition bushings are required here to put power to the ground efficiently, while maintaining good handling and traction.
Suspension to Subframe/Body
Your suspension, in the most simplified form, is an arrangement of levers that are made in such a way to keep the tires in firmest contact with the ground as all times. Because of their main function, they have great capacity to transfer NVH from the rough pavement to the body of the car and you. There are multiple bushings and mounts throughout the suspension system that need to be changed out every so often, usually between 100k and 200k depending on the car and conditions.
Control Arm Bushings
Control arm bushings are probably the most important bushings in this discussion. They are responsible from insulating the most basic NVH from the road to the body of the car. However, they also must maintain their shape and strength to do their job right, without them your alignment will sag, your tires will wear strangely, and your steering will lose definition and sharpness. We go through great lengths to try and offer complete control arms with bushings already pressed into them in order to make them easier to install.
Shock bushings
A common shock absorber will have a bushing at both the top and the bottom to help insulate the shock from minute high-frequency vibrations that you may get rolling over a road surface. That lets the shock get down to the nitty gritty of dampening the motion of the spring (they are also called dampers after all).
Strut Mounts
Struts are a special style of shock absorber that is designed to be hard mounted to the steering knuckle, and thus must be able to rotate unlike a shock. At the top there is a strut mount, a rubber bushing built into a bracket, and when these fail it can get scary. Extreme instances have shown failed strut mounts to launch the top of the strut up into the hood of the car. Commonly these are changed every time you change a strut, but some cars are more susceptible to mounting and bearing problems such as 03+ Saab 9-3’s, Mid 00’s Volvo’s, and late model BMW’s.
Sway bar bushings
The sway bar is a long torsion spring that connects both wheels of the car together, and resists one wheel from bounding or rebounding with too much of a difference from the other. This keeps the vehicle more flat and planted through corners. The bushings connect the sway bar to the subframe (or body of the car), and take a lot of abuse throughout their lifetime. When they go bad, space frees up and you can hear loud groaning squeaks as the car moves up and down, such as at a railroad crossing. You can try applying grease to them, but in some cases they should just be replaced.
Steering Rack Bushings
The steering rack bushings take a considerable amount of force when going around turns. While the rack is connected to the wheels and holding their steering angle tightly in place, the steering rack bushings hold the rack firmly to the subframe or body of the car. When these go bad, expect some play in the steering, and some steering deflection in turns. When neglected for too long, these can cause safety issues in the steering of your car.
Subframe to Body
The Subframe is held to the body/main frame with huge bushings. These subframe bushings take the grunt of both the engine and suspension pulling and twisting against the body of the car. When these bushings go, the car will feel less responsive and sluggish. What feels like body roll and chassis flex is most likely due to worn out subframe bushings when the car is past 100k miles, especially in very hot climates, or where there is a lot of salt used on the roads. Subframe bushings are often put off because of how hard they are to install, but we now carry Powerflex bushings that do not require a press to put in. Therefore, so as long as you can get the old ones out the installation will be much quicker.
