Before we get into why your suspension bush or bushings might be worn out and ready for replacement, let’s have a quick recap for those who aren’t entirely sure what or where these crucial parts of your car’s steering and suspension are.
What is a suspension bush?
So what exactly are suspension bushings or bushes? They’re rubber buffers that sit between two connected metal components. They appear throughout your car’s systems, not exclusively in the suspension; they’re usually made of rubber or polyurethane and look like fat, rubbery washers.
You’ll find suspension bushes in control arms, stabiliser bars, ball joints, tie rods, shock absorbers, strut mounts, and a host of other steering and suspension parts. Despite appearing as such a small and insignificant component, they play a major role in your car’s ride’s protection, comfort, and efficiency.
What does a suspension bush do?
The simplest way to understand how suspension bushings work is to compare them to the cartilage in your knees. The cartilage’s job is to prevent your bones from wearing while grinding against each other and provide a nice healthy spring in your step. As your knees bend and move thousands of times each day, the cartilage between those moving parts creates a flexible cushion, padding the gap, protecting both bones, and providing the silky-smooth operation of your stride.
Bushings do the same thing. They prevent contact wear, soak up all the bumps and vibrations from the road while making steering and braking smoother and your car easier to drive.
How do suspension bushes wear out?
Slowly. Sadly, just like the cartilage in your knees, your car’s rubber bushes wear out over time. As we get older, and after thousands, if not millions of steps, paces, and jumps, our cartilage dries up and wears out from a lifetime of operation—the same goes for bushings.
Given their location, suspension bushes are vulnerable to numerous destructive elements. All kinds of debris is thrown at the underneath of your car, and the changing weather conditions also add to the fatigue of the bushing material. As a result, the rubber material will eventually perish, dry out, and crack, or dirt, gravel, and tiny debris fragments can infiltrate the parts, causing wear and ultimately leading to their demise.
Thankfully, for drivers, bushings are far easier to replace than cartilage. You only need a competent mechanic—and not a surgeon!
The first time drivers know something is wrong with their bushes is usually at an MOT
Because the wear takes place slowly over time, and detection isn’t always easy to spot, given it could be any of the various components in your suspension system, deterioration in bushes is one of the more frequent MOT advisory faults.
Symptom 1: Your ride has become more uncomfortable over time
Without the additional vibration and shock absorption bushes provide, you may notice that your car’s ride is a little bumpier than usual. That said, we tend to jump to conclusions, guessing at bigger problems, assuming it’s the suspension components themselves. Whatever the issue, it’s important to get it checked out to ensure your continual safety while driving.
Symptom 2: Movement in the suspension while steering and braking
When bushes wear, the gaps between the moving parts they fill give way to movement and play. This could translate into a looser, shakier feel in the steering and poorer handling when steering and braking.
This is one of the problems with detecting bush wear in your rear suspension. Given they have little impact on braking and none with steering, there are significantly fewer symptoms to help you uncover bush issues. That’s why so many are spotted at MOT instead of any other time.
Where there’s significant movement, you may also spot uneven tyre wear. Without the tight, snug performance of a healthy bush, unwanted movement can affect wheel alignment, manifesting in wear along the edges of tyres.
Symptom 3: Clunking and rattling noises
When gaps appear between moving parts, they become easier to detect while driving over uneven surfaces, bumpy roads, and potholes. Clunking occurs during sharp turns and braking, where rattling happens driving down rough roads and gravelly streets.
Symptom 4: Squeaky suspension and bushings
Modern bushes are considered ‘permanently lubricated’, but in older cars, the fittings required regular lubrication to remain packed with grease. So even as a sealed unit, modern bushings still dry out, and when they do, you’re likely to hear them squeak.