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How to Replace a Complete Strut Assembly (And Why Not Bare Struts)

Replacing struts is well within reach for a home mechanic — provided you buy complete assemblies. The moment the job involves transferring a spring from an old strut to a new one, it stops being a routine job and becomes one with genuine injury potential. This guide covers the complete-assembly route and explains why that distinction matters. Why Complete Assemblies A complete strut assembly arrives with the strut, coil spring, upper mount, bearing and boot already assembled and preloaded at the factory. You unbolt the old unit and bolt the new one in. A bare strut requires you to compress the old spring with a spring compressor, transfer it, and release it onto the new strut. A compressed coil spring stores a very large amount of energy. When a cheap compressor slips or a hook releases, that energy goes somewhere, and the results have caused serious injuries. There are also practical benefits: the assembly replaces the upper mount and bearing, which are wear items and are frequently the actual source of a clunk or a binding sensation when steering. If you must use bare struts, have a shop do the spring transfer. Many will do it for a modest charge, and it is a reasonable division of labour. Before You Start Tools: socket set, breaker bar, torque wrench, jack and axle stands, penetrating oil, and often a pry bar. A second person is genuinely useful when manoeuvring the assembly into place. Look up the torque figures for the upper mount nuts, the lower strut-to-knuckle bolts, and the lug nuts. Apply penetrating oil to the lower strut bolts in advance. They are frequently seized, particularly on vehicles from salted-road regions. Replace in axle pairs. Mismatched damping between left and right makes braking and cornering unpredictable. Step 1: Loosen Before Lifting With the vehicle on the ground, loosen the lug nuts. On some vehicles it also helps to break the lower strut bolts loose while the suspension is loaded, though this depends on access. Step 2: Raise and Support Raise the vehicle and support it on axle stands. Chock the remaining wheels. Remove the wheel. Important: support the vehicle by the chassis, not the suspension, so the suspension can hang free. You need that droop to get the strut out. Step 3: Disconnect What Attaches to the Strut Depending on the vehicle, one or more of these will be mounted to the strut body: Brake hose bracket ABS sensor cable clip Sway bar end link Free each one and move it aside carefully. Do not stretch the brake hose or the ABS cable. Step 4: Support the Knuckle Place a jack under the steering knuckle or lower control arm to support the suspension. When the strut comes out, the knuckle will otherwise drop and hang on the brake hose, CV joint or ball joint. This step prevents a surprising amount of collateral damage. Step 5: Remove the Lower Strut Bolts Remove the bolts securing the strut to the knuckle. These are usually large and often seized. Use a six-point socket and a breaker bar. Steady force rather than sudden jerks. If a bolt spins without coming out, it may be rusted to its sleeve — penetrating oil, and sometimes the bolt must be driven out with a punch. Note the orientation of any camber adjustment bolts before removing them, and mark their position. Some vehicles adjust camber at this joint, and losing the setting means an alignment is mandatory. Step 6: Remove the Upper Mount Nuts Open the bonnet and locate the strut top mount, usually three nuts in the strut tower. On rear struts this may be inside the boot or under interior trim. Support the strut from below before removing the last nut, or the whole assembly drops. Step 7: Remove the Assembly Manoeuvre the strut out. It is heavier and more awkward than it looks, and on tight applications you may need to lower the knuckle further or turn the steering to gain clearance. Step 8: Fit the New Assembly Check the orientation. Struts are directional — the bracket and mounting holes must face the right way, and the upper mount studs must align with the holes in the tower. Lift it into position and start the upper mount nuts by hand. Do not fully tighten yet. Align the lower end with the knuckle and fit the bolts, again by hand initially. Refit the camber bolts in their marked positions if applicable. Torque the lower bolts to specification. Torque the upper mount nuts to specification. Reattach the brake hose bracket, ABS clip and sway bar link. A note on torquing: some vehicles specify that the lower bolts be torqued with the suspension at ride height rather than hanging. Check the procedure, because bushings that are clamped at the wrong position are preloaded incorrectly and wear quickly. Step 9: Reassemble and Finish Refit the wheel and lower the vehicle. Torque the lug nuts in a star pattern. Repeat on the other side of the axle. Get an Alignment This is not optional after replacing front struts. Removing the strut disturbs camber on most designs, and driving on a wrong alignment wears tires quickly — often visibly within a few thousand miles. Book the alignment before you start the job so the car is not sitting waiting. After the Job Expect the ride to feel firmer initially. New dampers control motion properly, which feels different after years of gradual degradation. Listen for knocks over bumps. A knock after installation usually means a fastener is not torqued or the upper mount is not seated correctly. Re-check lug nut torque after 50 to 100 miles. Common Mistakes Using a spring compressor without proper equipment and experience. The main reason to buy complete assemblies. Letting the knuckle hang. Damages the brake hose, CV boot or ball joint. Not marking camber bolt positions. Turns a straightforward alignment into a longer one. Torquing bushings at full droop when the specification calls for ride height. Replacing only one side. Creates uneven damping across the axle. Skipping the alignment. Costs a set of tires. Before You Order the Part Confirm front or rear, and check whether your vehicle has an electronically adjustable suspension — those use entirely different units that cannot be substituted with conventional struts. Verify trim level, since sport and heavy-duty packages often use different spring rates. Check whether the listing is sold individually or as a pair, and match the fitment chart to your exact year, trim and drivetrain.