Nuts, Bolts & Screws for 2016 Subaru Legacy 2.5i Limited

Suspension hardware gets treated as consumable until the moment it isn't.

On your Subaru Legacy, a control arm bolt carries the full load of that corner, a cupped washer decides whether a bushing stays where it was put, and a shim pack is what holds an alignment setting between services.

What Is in the Subaru Legacy Nuts, Bolts and Screws Range

The range covers the fasteners and hardware that suspension components mount with, in three groups.

A control arm bolt kit supplies the through bolts, nuts and washers for specific mounting points, including kits that add adjustment the factory did not provide. Lower control arm bolt kit and upper control arm bolt kit options are listed separately, since the two positions use different hardware.

Control arm washers cover the load spreading and locating hardware at arm pivots, supplied as kits with the nuts that go with them.

Sway bar link washers are the hardened cupped washers that sit either side of a link bushing, available universally rather than tied to one platform.

Service kits round it out, supplying the replacement hardware for specific Whiteline control arms so a worn bushing or a lost fastener does not mean a new arm.

Control Arm Bolts and Why They Matter

A control arm bolt is not an ordinary fastener and treating it as one causes problems.

A suspension control arm bolt passes through the bushing sleeve and clamps the arm to the subframe or chassis bracket, carrying every braking, cornering and acceleration load that corner sees.

Clamping force is what holds the joint, not the bolt shank taking load in shear. That is why torque specification matters and why a bolt that has lost its clamping force lets the arm move before anything stops it.

Length and diameter are both critical to the joint. A bolt even slightly long leaves thread where the shank should be bearing, and one slightly short leaves the nut without full engagement.

A lower control arm bolt generally sees the highest loads, since the lower arm carries more of the corner's weight and takes the braking torque reaction. An upper control arm bolt works less hard but sits in a joint that is often harder to reach.

Broken and Seized Control Arm Bolts

Any control arm bolt that has been in place for years will resist coming out, and knowing why helps.

The bolt passes through a steel inner sleeve in the bushing, and water collects in that joint. Corrosion forms between the shank and the sleeve rather than only on the threads, so the nut can come off cleanly while the bolt refuses to move.

A seized bolt frequently has to be driven out or cut, and a broken control arm bolt leaves a section inside the sleeve that has to be drilled or pressed out.

Penetrating fluid applied the day before works better than force applied on the day. Heat helps and needs care around bushings, brake components and anything with rubber nearby.

A bolt that comes out damaged never goes back in. Control arm bolt replacement kits exist for exactly this situation, and a rear control arm bolt or a rear lower control arm bolt costs a fraction of the labor already spent getting the old one out.

Cupped Washers and Sway Bar Link Hardware

Cupped washers are the most useful item in the range and the least understood.

A sway bar link bushing sits between two washers, and those washers do two jobs. They spread the clamping load across the face of the bushing rather than concentrating it at the bolt, and the cupped shape contains the bushing so it cannot extrude sideways under load.

Flat washers do neither of those jobs properly. A bushing clamped between flat washers squeezes out at the edges, loses its preload and starts allowing the movement the link should be controlling.

Hardened material matters just as much as the cupped shape. A soft washer deforms under the clamping load and the bushing loses its support as it does.

Universal kits in common sizes cover a wide range of applications, which is what you want on a wear item that goes through several sets over a vehicle's life.

Toe Adjustment Bolts and Lock Out Kits

Rear toe is where alignment hardware earns its place, and two approaches exist.

A toe bolt, listed as a rear toe adjustment bolt, uses an eccentric cam to move the arm's mounting position, changing the toe angle at that wheel. It gives adjustment on platforms that have little or none from the factory.

A toe lock out bolt kit does the opposite. Where a factory eccentric arrangement allows the setting to drift under load, a lock out kit replaces it with hardware that holds the position fixed.

That matters a great deal more than it sounds. A rear toe setting that moves under acceleration and braking means the vehicle steers slightly at the rear, which feels unsettled and wears tires fast.

Which you need depends on whether the platform's problem is a lack of adjustment or a lack of stability in the adjustment it has.

Shim Camber Kits and Bolt Packs

Shim kits adjust camber by changing the effective position of the arm at its mounting point.

The kit supplies bolts and a stack of washers or shims, and camber is set by moving shims from one side of the mount to the other. Move them and the arm's pivot shifts, taking the top of the hub with it.

The advantage of a shim kit is range. A shim stack can deliver more adjustment than an eccentric bolt, and the setting is mechanically fixed once torqued rather than relying on a cam staying put.

The trade off is that adjustment means dismantling the joint rather than turning a bolt on an alignment rack, so it is set once and left.

These suit platforms where rear camber goes out after lowering and the factory gave no way to correct it.

Service Kits and Replacement Bolt Hardware

A service kit supplies the replacement hardware for a specific control arm rather than the arm itself.

That distinction matters on a quality aftermarket arm. The arm body outlasts the bushings and fasteners in it by a wide margin, so replacing the whole assembly because a bushing has worn is throwing away the expensive part.

Kits typically include the bolts, washers and nuts for that arm, so a rebuild uses new hardware throughout rather than reusing fasteners that have been torqued and loaded for years.

Check the kit matches your specific arm part number, since hardware differs between arm designs even on the same platform.

Matching Hardware to the Joint for Your Subaru Legacy

Buying the right fastener comes down to four figures and a check.

Diameter has to match the hole and the bushing sleeve it passes through. A bolt undersized for the sleeve lets the arm move within the joint no matter how hard it is torqued.

Length has to suit the thickness of the clamped stack. The shank should bear through the joint with the thread starting beyond it, not partway through the clamped faces.

Thread pitch has to match the nut, which sounds obvious and catches people out on vehicles that mix metric pitches across the same platform.

Grade is the specification people ignore most often. Suspension fasteners are high tensile for a reason, and a hardware store bolt of the right dimensions is not the same part.

The check itself is simple enough to do. Measure what came out rather than ordering from a diagram, since a previous repair may have changed what is in there.

Why Subaru Legacy Factory Hardware Should Not Be Reused

Several fasteners in a suspension are single use by design, and more are single use in practice.

Anything torqued into its yield range stretches permanently. Retightening produces a fastener that feels right on the wrench while delivering less clamping force than it did new.

Nyloc nuts lose their grip once the nylon insert has been through a thread. A reused one holds for a while and is not doing the job it was specified for.

Corroded threads change the relationship between torque and clamping force entirely. The same torque figure on a corroded thread produces considerably less clamp, because friction is absorbing the effort.

Replacement hardware costs very little against the labor of accessing it, which is the whole argument for buying the kit rather than reusing what came out.

Torque Matters More on Suspension Hardware

Getting the number right is not optional here, and the reason is what the fastener is doing.

These are clamped joints relying on friction between the clamped faces. Under torque them and the joint moves, elongating the bolt holes and wearing the bushing sleeve. Over torque them and the fastener is taken past its useful range, which reduces clamping force rather than increasing it.

Torque bushed joints with the vehicle on its wheels at normal ride height rather than hanging on a hoist. A bush takes a set from the position it is clamped in, and one clamped at full droop is preloaded from the first corner.

Recheck after the first few hundred miles on anything newly assembled, since joints settle as they bed in.

And have the alignment set afterward where the hardware affects camber or toe.

Find Suspension Nuts, Bolts and Washers for Your Subaru Legacy

Select your Subaru Legacy to see the control arm bolt kits, washers and alignment hardware available for it, in front and rear fitments. Order replacement hardware with any suspension work rather than planning to reuse what comes out, since the fasteners are the cheapest part of the job and the easiest to get wrong.