If your car dives forward hard under braking, keeps bouncing after a speed bump instead of settling in one or two movements, or wanders slightly on the motorway with no obvious cause, your shocks or struts are most likely worn. Uneven tyre wear, especially cupping or scalloping across the tread, is another strong signal. None of these are things to ignore, since worn suspension increases stopping distances and reduces grip exactly when you need it most.
The bounce test, and why it only tells you part of the story
The classic way to get a rough read on your shocks without any tools is the bounce test. With the engine off, push down firmly on each corner of the car in turn and let go. A shock or strut in good condition will let the car rise once and settle almost immediately. If a corner bounces twice, three times, or keeps oscillating for a second or two before it stops, that corner’s damper has lost most of its control over the spring.
It is a useful first check, but it is not the full picture. A shock can be losing its damping gradually over tens of thousands of kilometres without ever failing the bounce test obviously, and problems like a leaking seal, a worn bush, or a damaged mount will not always show up from a driveway test. That is why a proper inspection on a hoist, where the shock, the mount, the bush and the strut top can all be looked at directly, is the only way to get a definite answer rather than a guess.
The signs worth paying attention to
Worn shocks and struts tend to show up in a handful of consistent ways. If you are noticing more than one of these at once, it is worth booking an inspection rather than waiting for something to get worse.
- Nose-diving under braking. The front of the car dips noticeably every time you brake, more than it used to when the vehicle was newer.
- Excess bouncing. The car keeps moving up and down after a bump or dip in the road, instead of settling quickly.
- Uneven or cupped tyre wear. Scalloped, wavy wear patterns across the tread (as opposed to simple edge wear from an alignment issue) point to the tyre losing consistent contact with the road surface as the shock struggles to control it.
- Wandering or vague steering. The car feels like it needs small, constant corrections on the motorway, or feels less planted than it should in a straight line.
- Body roll in corners. The car leans more than it used to when cornering at normal speeds, or the rear feels like it is following the front rather than staying settled.
- Clunking or knocking over bumps. This can point to a worn strut mount or bush rather than the shock itself, but it belongs in the same inspection either way.
Any one of these on its own might have another explanation, worn tyres, an alignment issue, or a tired bush somewhere else in the suspension. Together, though, they are a reliable pattern that points squarely at the dampers.
What this means for your WOF
A Warrant of Fitness inspection specifically checks for suspension components that are leaking, physically damaged, or allowing excessive movement. A shock absorber with visible oil weeping down the body, a torn or collapsed dust boot, a cracked mount, or a bush with too much play can be a fail item on its own, separate from any tyre or alignment issue it might also be causing. If your WOF is coming up and you have noticed any of the signs above, it is worth getting the suspension checked before the inspection rather than after, since a failed WOF for suspension usually means booking a second visit once the repair is quoted and parts are in.
Worn shocks also make the WOF’s braking and steering checks harder to pass cleanly, since a car that is bouncing or diving under braking is, by definition, not controlling its tyre contact with the road the way the standard assumes it should.
Do you need an alignment after replacing shocks?
It depends on the type of suspension your vehicle has. A basic shock absorber, the kind fitted separately from the spring on a live rear axle or some multi-link rear setups, generally does not affect wheel alignment when it is replaced, since it plays no role in steering geometry.
MacPherson struts are different. On most front-wheel-drive hatchbacks and many SUVs and utes, the front strut is a structural part of the steering knuckle assembly, not just a damper bolted alongside the spring. Replacing a strut can shift camber and caster slightly, particularly if the strut top mount or the way the strut sits in the knuckle changes even a small amount during the job. Because of this, an alignment check is the safer default after strut replacement, even if it turns out the numbers have not moved much. We will tell you at the time of your service whether your particular vehicle’s setup calls for one, rather than leaving it as a guess. If your vehicle is also due a wheel alignment or new tyres, it is worth booking both in the same visit so any camber or toe changes get picked up and corrected while the car is already on the hoist.
What affects the cost
Across New Zealand, shock absorber or strut replacement typically costs between $150 and $700 per corner, though the exact price depends on your vehicle, whether it is a simple shock or a full strut assembly, and the parts grade fitted. A few things push the number up or down. Strut assemblies, which include the spring and top mount as one unit, generally cost more than a standalone shock absorber. Larger 4WDs, wagons and utes carrying heavier loads often need a heavier-duty part than a small hatchback. Whether one corner needs replacing or all four also matters, since fitting new shocks or struts in pairs (both fronts, or both rears, together) is the usual recommendation for even handling. For an accurate quote for your vehicle, get in touch with our team.
Uneven tyre wear caused by worn shocks is also worth checking at the same time. If the tread is already scalloped or cupped, a tyre replacement alongside the suspension repair may be the more sensible call than trying to get more life out of tyres that have already worn unevenly.
Getting it checked
If your car is bouncing more than it should, diving under braking, or the tyres are wearing unevenly, book it in for a proper suspension inspection rather than guessing from the driveway. Our workshop is in Frankton, Hamilton, and services vehicles from across Hamilton and the wider Waikato. Call us on (07) 847 3339 to book a suspension check, or to get an inspection done alongside your next WOF or service.