How do I know if my suspension is worn out?
The bounce test and what it really tells you, how worn dampers show up in braking and tyre wear long before they leak, and why a broken coil spring is the one that means stop.
- Difficulty
- beginner
- Time
- 15 min
- Read
- 5 min
- Safety
- warning
Short answer
Worn dampers rarely announce themselves — the car simply feels floaty over crests, dives more under braking, and takes an extra bounce or two after a bump. Look for oil running down the damper body, uneven cupped wear on the tyres, and a nose that dips further than it used to. A broken coil spring is different: the car sits visibly lower on one corner, often with a knock over bumps, and it can cut a tyre. That one means stop driving.
Suspension wear is the classic slow fault. It happens over tens of thousands of miles, so the driver adapts to it without noticing, and the car only feels wrong again once it has been fixed. That is a real problem, because dampers do not exist for comfort — they exist to keep the tyre pressed against the road. A wheel that is bouncing is a wheel that is intermittently not steering and not braking, and every published stopping distance assumes it is doing both. This is why worn dampers show up as longer stopping distances in every test that has ever measured them, and why the MOT looks at them.
Safety
Step by step
- Do the bounce test, but know its limits.Push down hard on one corner of the car and let go. A healthy damper lets it come back up and settle, with perhaps one small overshoot. Two or more clear bounces suggests that damper is done. It is a crude test that catches badly worn dampers and misses moderately worn ones — a negative result proves nothing.
- Look at the dampers themselves where you can see them.Through the wheel arch, with the wheels turned for a better view, you can often see the damper body. A wet, oily streak running down it means the seal has failed and the damping oil is escaping. That is an MOT failure and a definite replacement.
- Notice how the car behaves rather than how it sounds.Excessive nose dive under braking, the back squatting under acceleration, floating over motorway crests, a sway that keeps going after a lane change, and a nervousness in crosswinds are all damper symptoms. They arrive gradually, so compare against a friend's similar car if you can.
- Read the tyres.Cupping or scalloping — regular dips of wear spaced around the circumference, which you can feel by running a palm around the tread — is the classic fingerprint of a damper letting the wheel bounce. The catalogue's tyre wear guide covers the full set of patterns.
- Look along the car for a broken spring.Park on level ground and stand back. A car sitting noticeably lower at one corner, or with an obviously smaller gap between tyre and arch on one side, has usually broken a coil spring. Look at the spring through the arch: a broken one often shows a clean fresh break, commonly at the bottom coil where road salt collects.
- Listen for the knock that goes with it.A single sharp knock over small bumps at low speed, worse on rough surfaces, is the classic broken spring or worn top mount noise. It differs from the general clonk of worn bushes, which tends to be duller and more spread out.
- Check the top mounts by feel.With the engine running and the car stationary, turning the steering slowly lock to lock sometimes produces a graunching or clicking from the top of the strut. That is a worn top mount bearing, and it often comes with a slight notchiness in the steering.
- Book it in rather than investigating further.Everything beyond this point requires the car in the air. Ask specifically for the suspension to be checked on a ramp and for the dampers to be assessed — and give them the symptoms, because a garage that knows you are getting cupped tyre wear and dive under braking will look in the right place.
Common mistakes
- Replacing one damper — The car then has different damping left and right, which is worse under braking and in an emergency swerve than two equally tired ones. They are always replaced in pairs across an axle.
- Assuming worn suspension is only a comfort issue — A bouncing wheel is not fully in contact with the road, so it is not fully braking or steering. Measured stopping distances lengthen significantly with badly worn dampers.
If it doesn't work
Car sits lower on one corner
Cause: Broken coil spring, or a failed air suspension unit on a car that has it — Fix: Stop driving it. A broken spring can rotate and cut into the tyre, and the car's handling is compromised. Have it recovered.
Knocking over bumps but the car handles normally
Cause: Worn anti-roll bar drop links or bushes — Fix: The cheapest thing in this whole family and by far the most common cause of a suspension knock. Ask for drop links to be checked first — they are inexpensive.
Oil running down a damper body
Cause: Seal failure — Fix: MOT failure and a replacement. Dampers are always replaced in axle pairs, because a new one on one side and a worn one on the other makes the car handle unevenly.
Car crashes over small bumps but is fine on big ones
Cause: Often over-inflated tyres or perished bushes rather than dampers — Fix: Check the pressures against the car's own placard first. It is free and it accounts for a surprising share of ride complaints.
Steering feels vague and wanders on the motorway
Cause: Worn track rod ends, ball joints or bushes, or alignment out — Fix: This is a play-in-the-steering problem rather than a damping one. It needs a ramp check — free play in a steering joint is both an MOT failure and a genuine safety issue.
Questions people ask
How long do shock absorbers last?
There is no fixed figure — it depends enormously on road surfaces, load and mileage, and they degrade gradually rather than failing at a point. Many are still original at high mileages and still legal, while being well past their best. Judge by symptoms and by an inspection on a ramp, not by a number.
Will worn suspension fail the MOT?
Leaking dampers, broken springs, excessive play in joints and corroded or damaged components are all MOT failures. Dampers that are simply tired but not leaking generally are not, which is why a car can pass an MOT and still handle badly.
Why do coil springs break in winter?
Road salt corrodes them, usually at the bottom coil where water and grit sit, and the cold makes steel more brittle. The classic pattern is a spring that snaps going over a speed bump or into a pothole on the first properly cold morning.