Don’t worry, we’re not going into gardening; this blog post deals with the various suspension bushes found in any car (also referred to as ‘rubbers’ or ‘bushings’ depending on who you’re talking to). They’re crucial and well worth investing in replacements if you want your car to drive at its best.
First up: what are suspension bushes?
Suspension bushes are found anywhere there’s a joint in the suspension system of a car. They cushion movement between two solid parts usually, helping to absorb sudden shocks through the suspension, but also reducing road noise transfer up through the suspension to the car’s occupants. There are all kinds of different bushes in the suspension system, some of the more commonly replaced ones are Wishbone bushes, control arm bushes, anti roll bar bushes and shock absorber bushes & mounts
Sometimes bushes are designed to intentionally allow a certain amount of movement in one direction to build compliancy into the suspension or introduce, for example, passive rear-wheel steering.
Bushes are usually made of rubber (natural or synthetic), but polyurethane is becoming more prevalent in certain areas of the suspension too and they’re favoured by keener drivers. You’ll find bushes everywhere, from the anti-roll bars to the steering control arms, ball joints and even the mounts for the dampers and suspension turrets. Over time and with mileage bushes will wear out. When bushes wear, excess play (unwanted movement) will be evident.
If the wear is severe you may be able to feel or even hear a difference in the cars steering or suspension whilst driving. The wear can manifest itself in all kinds of different ways – there could be vagueness in the steering, generally poor handling or braking, knocking, rattling or creaking from the suspension….or you may not notice any of the above!
How to tell if your suspension bushes need replacement.
Visually inspecting the bushes is one way to know if they need replacement. Over time, the material degrades due to temperature extremes, dirt and wear and it should be obvious if they’re cracked but it’s not an exact science, some worn bushes may look fine but could still be due for replacement. With the car raised off the ground and safely supported use a solid bar to lever the suspension components in various directions, compressing and releasing each bushing to ensure it’s still doing its job without too much movement. Really, this is something best left to the experienced and an NCT/MOT test failure might be the first time an average motorist hears about suspension bushes.
There are other subtle clues that something might be amiss. Uneven tyre wear, for example, can be a sign of a worn bush. Likewise, degraded comfort, handling and noise, though it’s likely that the bush’s effectiveness will have reduced slowly over time so not many will pick up on the changes until they get quite severe.
Replacing your bushes.
Some bushes are easier than others to replace, but all are fiddly. They can take a lot of physical strength to remove and replace and, at times, specialised pressing tools. At other times, it won’t be possible to replace just the bushing, as it will come part-and-parcel with another suspension component – e.g. the ball joint and steering control arm.
Anti-roll bar bushes are the most common that need replacing, as the anti-roll bars are constantly twisting. Most DIY mechanics should be up to the task of replacing these, though of course the complexity of getting to the bushes can differ from model to model and there can be several different bushes on the anti-roll bar. The easiest to replace are those between the anti-roll bar and the car itself, often referred to as ‘D’ bushes (as they are shaped like the letter D). It’s usually a case of removing two bolts, prying off a U-shaped clamp around the bush and then forcing it off the anti-roll bar. These bushes are usually split so you can remove them without taking the whole anti-roll bar off the car and you reverse the process with the new bush.
Either end of the anti-roll bar is usually threaded and held in place with a large nut and washer where it passes through the lower suspension arm. A big bush is found in the joint and if it can be removed (it can’t always), it takes some skill to press it out. Replacing it seems just as difficult at first, but if you use a long bolt with a nut, a large washer and a big socket to hold it in place, you can slowly press the bush into place without doing any damage. Note that oil products can damage rubber so don’t be tempted to use them to lubricate it.
Many anti-roll bars also feature vertical links (called ‘drop links’) to the suspension. It’s not unusual to have to replace these rather than the bushes at the joints and it’s not a difficult task. It should not be necessary to remove the wheels or the anti-roll bar itself. Just keep a close eye on how it all comes apart so you know how to put it back together.
It’s a good idea to have someone inspect the suspension bushes regularly. Ask your mechanic to do this at service time and before you invest in new tyres or even tracking. Worn or damaged bushes are not always obvious, but they make a huge difference to how a car drives and can wear out a brand new tyre in no time at all.
At MicksGarage we stock a huge range of suspension bushes for tens of thousands of different makes and models of car and light commercial – both modern and classic. Click here to browse