Control Arm Bushes

A control arm bush is the pivot connecting the arm to the chassis or subframe. It has to let the arm swing freely as the suspension travels while holding it precisely in place against everything else the road applies to it.

Control arm bushings are the most commonly replaced bushes on any vehicle, and when they go you feel it in ways that rarely point back to a part this small.

What Control Arm Bushes Do, and Why Worn Ones Move Your Alignment

The control arm is a lever, and that is the reason a bush at the pivot matters far more than its size suggests.

The arm pivots on bushes at the chassis end and carries the wheel at the other, so any deflection at the pivot gets multiplied by the length of the arm before it reaches the tyre. A millimetre of give at the bush becomes considerably more than a millimetre of unwanted movement at the contact patch, and because most arms use two bushes, both giving at once, the effect compounds.

What that movement does is change your alignment while you drive. Under braking the wheel is pushed rearward, through a corner it is loaded sideways, and each input shifts camber, caster or toe by however much the bush allows. The wheel alignment was measured with the vehicle standing still, which is why a car can read perfectly on the rack and still wander, follow ruts and wear the inside edge of a tyre.

Factory rubber allows more of that than most people realise even when it is new, because it is chosen for quietness rather than control. Once it has hardened and cracked after years of heat cycling and oil exposure, it allows a great deal more, which is why front control arm bushes are replaced so often on higher kilometre vehicles.

Split Front Lower Control Arm Bushes and What to Look For

The most visible failure on a control arm bushing is a split, and it is worth knowing what you are looking at before you order anything.

Rubber bushes are bonded to a metal outer sleeve. As the material hardens with age that bond fails, and the rubber begins to separate and tear away from the sleeve. Once that has happened the arm can move meaningfully at the pivot, and it will not improve on its own.

Front lower control arm bushes are where you see it most, because that arm does the heaviest work and the lower arm bushes take the brunt of everything the road applies. Look for cracking across the face, material squeezed out past the edge of the housing, a visible gap where the rubber has pulled away from the outer sleeve, or the arm sitting off centre in its mount rather than square.

A bush can also be finished without looking dramatic. If you can lever the arm against its mount and see movement at the pivot rather than flex in the arm itself, that bush has had it regardless of how it appears.

Upper and Lower Control Arm Bushings Are Different Parts

Control arm bushes are described by position, and getting it right matters more than anything else when ordering.

The first split is upper or lower, since a double wishbone layout has arms at both levels while a strut suspension usually has only the lower. Upper control arm bushings are a different part to lower control arm bushings even on the same vehicle.

From there they are identified by where they sit on the arm, normally inner or outer, and on arms with two inner pivots they separate into forward and rearward. Add front or rear of the vehicle and you have the full description, so a front lower control arm bush and a rear lower control arm bush are entirely different parts.

This matters because the two inner bushes on the same arm are frequently different sizes and different hardnesses, with the rearward one often larger and softer since it absorbs fore and aft impact while the forward one handles lateral location. Ordering the wrong one of a pair is the most common mistake made with these, and it is worth checking a diagram for your specific vehicle before you commit.

Depending on the shape of the arm you will also see these listed as A-arm or wishbone bushes. They are the same component doing the same job.

Symptoms of Worn Control Arm Bushes

• A dull clunk or thud from the front over bumps, driveways and speed humps
• A single knock when taking up drive, changing gear or lifting off the brake
• Steering that feels vague and wanders, needing constant correction
• The vehicle pulling to one side under braking
• Shudder or vibration through the wheel when braking from speed
• Uneven tyre wear, most often on the inside edge
• An alignment that will not hold specification between services
• Visible cracking, splitting or separation in the control arm bushing material
• Play at the pivot when the arm is levered against its mount
• A roadworthy or inspection report listing play at the control arm

The noise is usually the last of those to arrive rather than the first. By the time something clunks, the geometry has been moving under load for a long while and the tyres have been paying for it.

Control Arm Bushes or a Complete Arm

Both are legitimate repairs and the right one depends on what has actually failed.

A control arm bush kit on its own makes sense when the arm is straight, the mounting eyes are round, the ball joint is still tight and the ride height has not changed. That covers the majority of vehicles that come in with a clunk, and it is the cheapest route by a wide margin.

The complete arm is the answer when both ends are due, when the arm is bent or corroded, when a mounting eye has worn oval and will no longer hold a bush, or when the ball joint is pressed into the arm and has failed.

Worth knowing that the arm has to come off the vehicle for either job, so the labour is much the same. Once more than one thing on an arm is due, a complete assembly frequently works out better value than rebuilding it.

If the vehicle has hit something hard and the alignment has never been right since, measure the arms against each other before spending anything on bushes. A bent arm cannot be corrected with new bushes, and a few millimetres of deflection is invisible while completely changing where the wheel sits.

Control Arm Bushing Replacement Cost and Where the Money Goes

Control arm bushing replacement cost is dominated by labour rather than parts, and understanding that is how you spend less on it.

Nearly every control arm bushing requires the arm off the vehicle and the old bush pressed out, and that work is identical whether you replace one bush or every bush on the arm. Pay for a teardown, press work and an alignment today for a single position, then pay for all three again next year for the one beside it, and the labour has cost far more than the parts ever did.

Doing both bushes on an arm at once, and ideally both sides, is the straightforward way to avoid that. The same logic makes bushes almost free in labour terms if the arm is already coming off for a ball joint, new springs or any other front end work.

When comparing quotes, the numbers that actually move the total are how many positions are being done, whether the arms have to come off, and whether the wheel alignment is included in the price.

How to Press Control Arm Bushings In Without Ruining the Arm

Most positions need a press, and a correct diameter press tool is what keeps the arm eye intact. Improvising with sockets or old bearing shells is how arms get ruined, and an arm costs considerably more than the tool would have.

Check the eye once the old bush is out. A bore worn oval will never hold a new bush properly and means the arm itself needs replacing rather than rebushing, and finding that out before you press one in saves doing the whole job twice.

Fit the crush tubes and sleeves supplied, because the tube carries clamping load from the bolt and a bush fitted without one gets crushed the moment the fastener is torqued.

Grease on assembly with a lubricant made for polyurethane. Silicone and PTFE based greases are correct, while ordinary lithium and petroleum based greases can degrade the material over time. Grease the bore and the crush tube, since a dry bush wears its way to a fit and squeaks.

Torque with the vehicle on its wheels at ride height rather than hanging at full droop. Whatever position a bush is clamped in becomes its neutral position, so one tightened at droop spends its life twisted and binds from the first kilometre. More new bushes are ruined by this than by anything else and it costs nothing to get right.

Do both sides, then finish with a wheel alignment, since removing play changes camber and toe immediately and the old settings no longer apply.

Find Control Arm Bushes for Your Vehicle

Of all the repairs in our suspension bushes range, worn control arm bushes are the most common fix. If the arm itself is bent, Nolathane's control arms range has a full replacement.

Select your vehicle to see every control arm bush position available for it, or search by size if you are working on something the fitment guide does not cover. Every Nolathane component is backed by our warranty, a fitment guarantee and 60 day returns.