Tesla S/X/3/Y: sway bar end links — knocking on small bumps

Summary

Sway bar end links (links / "kostochki" / sway bar end links) connect the anti-roll bar torsion to the knuckle/lower control arm. Inside — a pair of ball joints in boots. As the joints wear, play develops → metallic knock/rattle on small bumps, especially at slow speeds and in cold weather. It's the cheapest and one of the most common causes of suspension knocks in a Tesla — but before replacing them, you need to verify it's actually the links and not a strut top mount/control arm/brake bracket.

Symptoms / Diagnosis

• "Clack-clack" on washboard surfaces and asphalt cracks at 20–60 km/h.
• On a lifted car, rocking the wheel by hand at top/bottom — slight knock transmitted to the link.
• Wiggle the sway bar torsion with a pry bar — should sit in its mounts without play; the link itself plays.
• Knock intensifies in the cold and disappears on warm dry asphalt — typical for boots in links.
• If the knock is dull and low-frequency, transmitted into the body — more likely top mounts or arm bushings, not links.

What to do

1) Diagnostics. On a lift go through the list: end links → top mount → lower ball joint → upper arm → sway bar bushings → rear pads/brackets. Old trick: remove an end link on one side, drive — if the knock disappears, that's the culprit.

2) Platform differences.

• Model 3 / Y: front end link — a simple "kostochka" with ball joints, replacement is one of the easiest jobs on the car (15–30 min/side). Rear end link is similar in idea but attaches to the lower arm and knuckle.
• Model S / X: different design — pre-Refresh and Palladium differ. On S 2012–2016 front there are two different PNs (RWD/AWD). On X front — a long link (PN 1027391-00-B), rear short (1027491-00-A). On S rear — 6007100-00-A. Due to length and geometry the S/X job takes longer.

3) Replacement options.

• Tesla OEM — usually pricier with no particular durability advantage, rarely praised on forums.
• Lemforder / Moog / Mevotech aftermarket — proven middle ground.
• Patron, Technorot, CTR — budget; one chat owner noted that Technorot links lasted 70,000 km on Model S.
• AliExpress — a lottery: boots may leak in 5–10k km, or may last properly. Take only branded (CTR, GSP, GMB), not "no name".
• Tuning — Unplugged Performance, SPL make adjustable links on spherical bearings, but they're for the track, not for silence.

Replace as a pair only (left+right on one axle), otherwise the second one will follow shortly.

Belarus budget

Parts (per pair):

• Mid-range aftermarket (CTR/Patron/Lemforder): $25–60 per pair.
• Tesla OEM or Moog/Mevotech: $60–120 per pair.
• AliExpress unbranded: $10–25 (see warning above).

Labor (Minsk, ~$50/h):

• Model 3 / Y, front, pair: 0.5–0.7 h → ~$25–35.
• Model S / X, front, pair: 0.8–1.2 h → ~$40–60 (longer, sometimes nuts seize).
• Rear links (all models): 0.6–1.0 h → ~$30–50.

Total range: from ~$50 (one axle 3/Y, budget aftermarket, DIY — parts only) to ~$200–220 (full replacement of both axles on S/X at a shop with OEM).

DIY notes

• Before work, disconnect 12V (negative terminal) — a general habit for any suspension work on Tesla.
• On S/X, link nuts often seize to the ball studs — the nut spins with the stud. Helps: 5 mm hex in the end of the stud (per service manual) or pipe wrench + WD-40 a day ahead.
• Tightening torque — per the service manual: on 3/Y the rear nut is usually ~50 N·m. Don't go "by feel", or you'll strip the thread or crush the boot.
• After replacement, check clearances: the sway bar torsion should move without scraping against boots and body.
• Alignment after end links isn't required — they don't affect angles.

Links / Sources

• Mountain Pass Performance — diagnosing M3/Y suspension noises: https://www.mountainpassperformance.com/diagnosing-suspension-noises-on-the-tesla-model-3-model-y/
• TMC — discussion of links on Model S: https://teslamotorsclub.com/tmc/threads/front-suspension-sway-bar-links-possible-rattling.126752/
• TMC — sway bar issues, general symptoms: https://teslamotorsclub.com/tmc/threads/sway-bar-issues.220630/
• Tesla Service Manual — Stabilizer Bar Link (Palladium): https://service.tesla.com/docs/ModelS/ServiceManual/Palladium/en-us/GUID-E45B4137-BE1D-4FC0-A797-C576B5486EE4.html
• YouTube — How to Replace the Sway Bar Link on a Tesla Model 3: https://www.youtube.com/watch?v=p3CsGx7Y7VE
• YouTube — Tesla Model S Sway Bar Links Replacement DIY: https://www.youtube.com/watch?v=sqYjutxGoUI

Community experience

From the TESLA owner's group BELARUS chat: end links come up regularly — both on 3/Y and on S.

Additional observations:

1. For a rattle on the front-right over small bumps, experienced owners' first thought is the sway bar end link (#23127).
2. Sometimes end links are checked several times — no play, but the knock remains. Then dig into top mounts or wheel hub bearings (#194554).
3. Among budget aftermarket brands — Technorot lasted 70,000 km on Model S without issues (#70589). On M3 they praise Patron from ZAP.by (#70590).
4. Sometimes end links + top mounts + strut rod cushion are replaced and the knock remains — worth checking the brake pad clips, they often rattle (#341955).