Sway Bar Link for 2013 BMW 135i Base

A sway bar link is the short connector between the end of the sway bar and the suspension. It carries load from one side of your BMW 135i across to the other when the body leans, and everything the bar does depends on it.

You will see them listed as swaybar links, sway bar end links, a stabilizer link or a stabilizer bar link depending on the catalog. They are the smallest and hardest working part in the assembly, which is why sway bar links are among the most replaced components on any vehicle.

What a Sway Bar Link Does on Your BMW 135i

A sway bar resists body roll by twisting, and it can only twist if something applies force to its ends. Applying that force is the link's entire job.

When one wheel rises relative to the other, the link on that side pushes or pulls the end of the bar, the bar winds up along its length, and it pushes back against the movement. That resistance is what keeps the car flat through a corner. Without the links, the bar is a piece of steel bolted to the chassis doing nothing whatsoever.

Because the link sits between the bar and a suspension component that is constantly moving, it also has to pivot through its own arc as the suspension travels. That requires a joint at each end, and those joints are what wear out.

Whatever the Link Absorbs, the Bar Never Gets

This is the part most people underestimate, and it matters more the better your bar is.

Any movement in the link is load that never reaches the bar. A worn ball joint, a perished bushing or a flexing link body all do the same thing, soaking up the first part of the input and delivering whatever is left. The bar is still there, still the correct rate, and quietly doing less than it was designed to.

That is why fitting an upgraded sway bar to a car with tired links wastes part of what you paid for. It is also why the settings on an adjustable bar stop feeling different from each other once the links have play in them. Those settings are deliberately fine, and fine differences need a rigid system to be felt at all.

If you have fitted a bigger bar and felt underwhelmed, the links are worth checking before you conclude the bar was the wrong choice.

The BMW 135i Rattle That Follows Small Sharp Bumps

Worn links produce one of the most recognizable noises in suspension work.

Sway bar link noise is a light, fast rattle or knock rather than a heavy thud, and it follows small sharp inputs rather than large ones. Parking lot speeds over broken pavement, driveways, speed bumps and expansion joints are where you hear it, and it often disappears completely on smooth road. Plenty of people describe it as sounding like something loose rolling around in the trunk.

That character is what separates it from the other suspects. Sway bar bushings at the center of the bar squeak and creak rather than rattle, and that noise changes with the weather, showing up on cold mornings and after rain. Control arm bushings make a heavier, duller thud that gets worse under braking. Ball joints knock when the wheel is turned and loaded rather than when the suspension moves vertically.

Checking for it is quick enough, because with the car safely supported grab the link and try to move it by hand. Play at either end means the joint has gone, and you can usually see a torn boot or cracked bushing material at the same time.

Symptoms of a Bad BMW 135i Sway Bar Link

• A rattle or knock from the wheel area over small sharp bumps, worst at low speed
• Noise that gets worse on broken pavement and disappears on smooth road
• A knock felt through the steering wheel when turning at low speed
• More body roll in corners with slower settling than the car used to have
• Play you can feel by hand at either end of the link
• A split or torn boot at a link joint, or visible cracking in a bushing
• A bent link, or one hanging loose after the joint has separated
• An adjustable sway bar whose settings no longer feel different from each other

Is It Safe to Drive Your BMW 135i With a Broken One?

A broken sway bar link is not the same as a broken ball joint, so it is worth keeping in proportion rather than panicking about it.

If a link separates, the sway bar loses its connection to the suspension on that side and simply stops working there. The car does not become undriveable, the wheel stays attached, and steering and braking are unaffected. What you lose is roll resistance, so the car leans considerably more in corners and feels vague and unsettled, particularly in an emergency lane change where you would most want it to behave predictably.

The real risk is what the loose end does next, because a broken link is still bolted at one end and free at the other, which means it can swing into a tire, a brake line or a CV boot. If one has broken, remove the loose piece rather than leaving it hanging while you arrange the repair.

So it is drivable in the short term at moderate speed, with the understanding that the car handles worse than you are used to. It is not something to leave for months.

Adjustable BMW 135i Links and Why Length Matters

A link has one correct length, and it is decided by where the two mounting points sit with your BMW 135i at its normal ride height.

Change that ride height and those points move apart or closer together. Lower a car and the geometry shifts one way, raise it and the opposite happens. Either way the bar ends up preloaded, already part way through its travel before the car has moved, and unable to work evenly from side to side.

Adjustable links have a threaded body that can be set with a wrench while the car sits on its wheels, which lets the length be dialed in precisely after any ride height change. On an adjustable bar they also let you use the full range of settings rather than whichever ones the link happens to permit.

Set them with the car on all four wheels at ride height, never at full droop on a lift. Neutralize them so both ball ends sit in the middle of their range, which is where the joint has its full articulation, and check both sides measure the same. Never force a link into place to make it reach, because a preloaded link puts constant load through the bar, the mounts and itself until one of the three gives way.

Ball Joints, Bushings and Rebuildable Links

Links are built two ways and which you have decides whether anything can be serviced.

Ball jointed links use a sealed socket at each end with a rubber boot over it, looking much like a miniature tie rod end. Nothing inside can be replaced, so once the joint develops play or the boot splits, the whole link gets replaced.

Bushing style links use a bushing at one or both ends, either pressed into an eye or stacked over a stud with washers and a nut. On these the bushings are a wear item you can replace on their own, which is a fraction of the cost of a new link.

Our adjustable links fall into the second group deliberately. Service kits supply the replacement bushings and hardware for specific link part numbers, so a link that has covered serious miles gets rebuilt rather than thrown away, and whatever length you set stays exactly where you set it.

What BMW 135i Replacement Costs and Why Quotes Vary

Sway bar links are among the least expensive suspension parts on any vehicle, and the labor is minimal because nothing needs pressing and no alignment is required afterward.

Each link is held by a nut at each end, and on a good day both sides are done inside an hour. The variable is corrosion, since links live in the worst position on the car for road salt and grit, and a seized nut turns a quick job into cutting the old link off. Shops price that risk in, which is why sway bar link replacement cost varies more than the parts bill would suggest.

Replace them in pairs, because both sides have covered the same miles, the parts are inexpensive, and doing one side means going back under the car for the other before long. If the sway bar bushings are being done at the same time, the combined job costs very little more than either on its own.

Cutting Off the Old Links on Your BMW 135i

This is one of the more approachable jobs on the car, since the link unbolts at each end and the new one goes straight in.

Expect a fight at the nuts, where penetrating fluid and patience beat force, and where a nut will not move, cutting the link off is the correct answer since it is being replaced anyway. Many links have a hex recess in the end of the stud so you can hold it while turning the nut, which is the trick that makes the job possible when the whole assembly wants to spin.

Do not overtighten anything, because crushing a bushing flat or over torquing a ball joint stud removes the compliance the link needs in order to pivot.

Grease any polyurethane bushings on assembly with a silicone or PTFE based lubricant rather than a lithium or petroleum based one, which can degrade the material over time.

Do both sides, check the sway bar bushings at the center of the bar while you are underneath, and recheck the fasteners after a few hundred miles.

Find Sway Bar Links for Your BMW 135i

End links work hand in hand with the bar, so check our sway bars and sway bar kits for more body roll control.

Select your BMW 135i to see the front sway bar links, rear sway bar links, adjustable links and sway bar link kits available for it. Every Whiteline component is backed by our warranty, a fitment guarantee and 60 day returns.