Car suspension problems can be a real pain to diagnose and fix, in this post I will go over the common suspension noises including coil springs, top mounts, shock absorbers and more to help you solve your unwanted noises.
General Suspension Noises
The suspension consists of lots of moving parts under stress while driving, so some noises when turning or going over bumps are just to be expected. This is especially true on older cars with worn suspension components and bushings.
You can end up with slack in multiple suspension components which together can result in some very sloppy handling, creaks, groans and knocking noises while driving down the road or turning corners.
To compound this issue, the UK’s congested road networks have led to some pretty awful road surfaces for your car’s suspension to take on and premature suspension components and bushing wear is a common occurrence and often leads to common suspension noises.
Broken Coil Spring Noise
Broken springs are one of the most common causes of suspension noise. Broken coil spring noise can manifest itself as a loud knocking when going over bumps, and if it’s on the front axle then you can even have coil spring noise when turning the steering.
The noise can be a simple suspension clunk but if you’re really unlucky then you can end up with some quite irritating chiming noises or a resonation as you drive on certain road surfaces.
But what causes coil springs to break? Some types of car are a lot more susceptible to broken coil spring noise than others and it generally comes down to the design of the car’s suspension from the factory.
BMW’s are particularly notorious for this spring snapping issue with their rear springs and it’s an issue I have experience with as I’ve got a red BMW E46 M3 that loves to snap rear springs.
For a while it seemed to be an annual occurrence that one of the rear springs would snap, despite replacing them multiple times with both OEM and upgraded Eibach Pro springs.
I spent a lot of time trying to figure out what causes coil springs to break on these cars, but the eventual solution to this for me was to replace the top and bottom rubber spring pads. These are rubber discs (available in various thicknesses) that sit between the spring perch and the coil spring itself.
The source of the problem was embedded grit within the old rubber pads gnawing away repeatedly at the coil spring over the course of a year, and making a weak spot inviting rust. To where the coil spring eventually snapped.
I was glad to solve that one as treating the rear coils as consumables was starting to get expensive!
Additionally to this experience, I’ve recently acquired a project BMW E30 that’s in rough shape, and before its MOT I noticed that it suffers from the same problem as the BMW M3 with a very similar rear suspension design. Both the E30’s old rear coil springs were snapped, but with no noise symptoms so it went unnoticed up to that point.
As broken coil springs are an MOT test failure, I was forced to replace them pronto so it would pass, but at least I know what causes coil springs to break now so I can avoid it and this type of common suspension noises going forward.
Bad Shock Absorber Symptoms & Noise
Driving with a broken shock absorber is never advised as it can severely hinder the handling characteristics of a car and potentially lead to loss of control.
However, different shock absorbers can wear at different rates, and if the seals are intact they may never leak or show any visual telltale signs of failure.
If you’re trying to figure out if your shock absorbers are worn, it can often manifest itself in bouncy handing. If your car has soft suspension you may be able to press down on one corner and observe the suspension bouncing as it settles back to its resting state.
The job of the damper or shock absorber is to dampen the compression and rebound of the suspension, a properly functioning strut will aid the suspension in returning to its resting state smoothly and without allowing bounce.
Bad shock absorber symptoms and noise can be pretty jarring as you drive around, particularly on uneven roads. Badly worn shocks can cause an unpleasant knocking noise.
It’s also worth noting that rear shock absorbers are usually independent of the spring, as in not coilover suspension. A common place for these to wear and knock is at their top and bottom mounting points which can feature rubber bushings that perish with age.
Top Strut Mount Noise
When one refers to the top mounts on a car, they’re usually talking about the bearing connection at the top of the front suspension strut which bolts to the underside face of the suspension turret that can be seen within the engine bay.
Top strut mount noise is quite a common issue as these parts are hard to inspect and even harder to replace, which can often mean they go completely ignored throughout the life of a car.
The function of these top mounts, or top hats, is to connect the top of the suspension to the cars body while allowing the strut to turn as the steering is turned. This is the bearing element of the top mount.
In my experience, it’s quite unusual to find worn top mounts manifesting itself through a rough feeling as you turn the steering wheel, but logic means you might expect this to be the case. The usual source of top strut mount noise is a vertical movement allowed between the steering bearing and the solid part of the top mount.
These two parts are often manufactured together with a solid rubber bushing to take some of the shock out of big suspension bumps.
While a rough feeling through the steering is uncommon, a knocking or clunking noise as you turn the wheels through certain steering angles is a common top strut mount noise symptom that can come from this issue.
It’s worth noting that rear top mounts are a common cause of top strut mount noise too and another one of the common suspension noises. These are usually of a more simple design than the fronts and thus smaller. They don’t require the same type of bearing as they don’t perform a steering function.
Checking these from the top often requires a partial strip of your car’s boot lining which can be a pain. It’s always worth listening out and trying to work out which corner your suspension noises are coming from before getting to work or buying parts.
Worn Bushings Car Noise
Worn bushings are a very common suspension noise source. Many of the suspension components on your car contain rubber bushings as a result of the manufacturers quest to reduce noise, vibration and harshness (NVH for short) in their car.
The trouble with rubber bushings is that they don’t last all that long in the grand scheme of things they perish over time and even split or tear preventing them from performing their function adequately and leading to some unpleasant work bushings car noise that can be heard from inside the cabin.
With so many potentially worn bushings under your car connected to the suspension, these can be a real pain to correctly diagnose and solve. These can manifest themselves in all kinds of ways including the common suspension knocking noise over bumps, or even the more unusual squeaking noises.
Once you’re under the car however, it can be pretty easy to spot a badly torn, or split bushing, and really perished ones can crumble away with a few pokes from a screwdriver.
It’s quite normal to see some surface cracking on rubber bushings even when they aren’t worn out so it’s wise to get the pry bar out and give each bush a flex and a prod to work out for sure which one is the offending item.
Worn bushings car noise can be the most painful to solve as it can often be multiple bushings working, or not working, together that can cause it. It’s also worth bearing in mind that when one rubber bushing is deteriorated, the others won’t be far behind being the same age themselves.
If your car is a keeper, at this point it’s often worth upgrading to polyurethane suspension bushings at this point. Polybushes aren’t usually much more expensive than their rubber OE counterparts, but can last a lot longer. They are usually stiffer too so can lead to handling and performance improvements for your car.
The trade-off here is a little more of that NVH transmitting into the cabin, and if you don’t make sure they are correctly greased (and top up their grease every so often) polybushes themselves can lead to some pretty unpleasant common suspension noises and can squeak and squeal as they move around too.
Ball Joint Noise
When you mention ball joints in automotive terms, you could be referring to any one of multiple suspension parts on your car, depending on how it’s equipped.
Ball joint noise is one of those very common suspension noises can be as a result of any one of these moving connection components failing so to diagnose this one properly, you will certainly want to remove a wheel and get under the car to track down the perpetrator.
The most common one would be the steering ball joint, and there is often a top and bottom ball joint setup, particularly on larger cars. These ball joints enable the wheel to be held to the cars suspension system while simultaneously allowing the steering to function to turn the front wheels.
Over time, you can get ball joint noise as they wear and the grease escapes allowing friction to occur. The symptoms of this are sloppy or vague steering, a slight wandering as you try to drive the car in a straight line, and also ball joint noise which is almost always a knocking or clunking.
If you listen carefully you can often work out which side your ball joint noise is coming from well before you get under the car to track it down.
Once under the car, these are usually easy to spot using a pry bar and applying some pressure onto each joint to track down the loose one.
Conclusion on Car Suspension Noise
To conclude this article, it’s worth noting that common suspension noises don’t always spell doom for your car. Many older cars can remain perfectly safe to drive around with worn and tired suspension components and your MOT will ultimately determine whether it’s time to replace them.
A quick summary on the most common sources of these noises is as follows:
- Coil Springs
- Shock Absorbers
- Top Mounts
- Bushings
- Ball Joints
If your car is an older performance car, or simply one you love and want to keep indefinitely, renewing the suspension system can really breathe new life into the car while also avoiding those common suspension noises. Sometimes a refresh can yield a remarkable transformation to your cars handling characteristics and improve driving enjoyment.