Mercedes-Benz bulletin LI33.20-P-078406
What it saysComplaint Creaking noise, in irregular sequence when driving slowly in combination with slight steering movements and/or Creaking/crackling noises from the area of the wheel bearing on the front axle when cornering… NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated Jul 8, 2026, received Sep 27, 2024, about the suspension — 8 documents under this number. It names 122 model years (2016–2026). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationComplaint Creaking noise, in irregular sequence when driving slowly in combination with slight steering movements and/or Creaking/crackling noises from the area of the wheel bearing on the front axle when cornering/ maneuvering. Sound file attached for comparison. MUST match noise for proper diagnosis. NOTE: Steering functionality is not affected. Cause Contact area between wheel bearing and steering knuckle. See also: LI35.30-P-058566 (Axle Half Shaft noise when changing direction - Front) LI33.30-P-056665 (Axle Half Shaft noise when changing direction - Rear) LI40.10-P-059248 (Wheel cracking noise when cornering) Remedy 1. Perform Operation A and evaluate by testing vehicle. 2. If noise is still present after re-testing: • If 192/232 chassis, verify FIN is in the listed range below in "Operation B" and perform. • If not 192/232 chassis or vehicle is a 192/232 not in the listed FIN range, additional verifications of where the noise is coming from are needed. Use multiple channel NVH method to narrow down location. Verify the LI's listed above were completed or if there are other similar noises associated with the chassis (Example: 192/232 also has under panel noises and an associated LI). Operation A: 1. Clean contact surfaces of wheel bearing and steering knuckle with brake cleaner (see areas marked blue in pictures "2.jpg" and "3.jpg"). NOTE: The front area of the wheel bearing and the seals must not come into contact with the cleaner, otherwise, the sealing rings will be damaged. 2. Clean threads of wheel bearing mounting. 3. Thinly coat contact surfaces of wheel bearing, steering knuckle, and axle mating face with Molykote (annular joint grease) (see areas marked blue in pictures "2.jpg" and "3.jpg"). NOTE: Axle mating face greasing is also covered in LI35.30-P-058566 and LI33.30-P-056665. Operation B (Only applies to 192 and 232 in listed FIN range): Only affects vehicles up to FIN end number: • Model series 192: xxx xxx xx 002 876 • Model series 232: xxx xxx xx 022 312 1. Replace steering knuckle. 2. Wheel bearings do not need to be replaced.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI33.20-P-078406 | Service bulletin | Jul 8, 2026 | 11035003 | PDF, 469 KB |
| LI33.20-P-078406 | Service bulletin | Jul 7, 2026 | 11034932 | PDF, 469 KB |
| LI33.20-P-078406 | Service bulletin | May 12, 2026 | 11032599 | PDF, 277 KB |
| LI33.20-P-078406 | Service bulletin | Apr 17, 2026 | 11031367 | PDF, 277 KB |
| LI33.20-P-078406 | Service bulletin | Jul 25, 2025 | 11021108 | PDF, 279 KB |
| LI33.20-P-078406 | Service bulletin | Jan 28, 2025 | 11013183 | PDF, 278 KB |
| LI33.20-P-078406 | Service bulletin | Nov 21, 2024 | 11010750 | PDF, 278 KB |
| LI33.20-P-078406 | Service bulletin | Sep 26, 2024 | 11008070 | PDF, 278 KB |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themand 56 more on this site: 2022 Mercedes-Benz EQS, 2016 Mercedes-Benz GL-Class, 2026 Mercedes-Benz GLC-Class, 2025 Mercedes-Benz GLC-Class, 2024 Mercedes-Benz GLC-Class, 2023 Mercedes-Benz GLC-Class, 2022 Mercedes-Benz GLC-Class, 2021 Mercedes-Benz GLC-Class, 2020 Mercedes-Benz GLC-Class, 2019 Mercedes-Benz GLC-Class, 2018 Mercedes-Benz GLC-Class, 2017 Mercedes-Benz GLC-Class, 2016 Mercedes-Benz GLC-Class, 2026 Mercedes-Benz GLE-Class, 2025 Mercedes-Benz GLE-Class, 2024 Mercedes-Benz GLE-Class, 2023 Mercedes-Benz GLE-Class, 2022 Mercedes-Benz GLE-Class, 2021 Mercedes-Benz GLE-Class, 2020 Mercedes-Benz GLE-Class, 2019 Mercedes-Benz GLE-Class, 2018 Mercedes-Benz GLE-Class, 2017 Mercedes-Benz GLE-Class, 2016 Mercedes-Benz GLE-Class, 2026 Mercedes-Benz GLS-Class, 2025 Mercedes-Benz GLS-Class, 2024 Mercedes-Benz GLS-Class, 2023 Mercedes-Benz GLS-Class, 2022 Mercedes-Benz GLS-Class, 2021 Mercedes-Benz GLS-Class, 2020 Mercedes-Benz GLS-Class, 2019 Mercedes-Benz GLS-Class, 2018 Mercedes-Benz GLS-Class, 2017 Mercedes-Benz GLS-Class, 2016 Mercedes-Benz GLS-Class, 2026 Mercedes-Benz S-Class, 2025 Mercedes-Benz S-Class, 2024 Mercedes-Benz S-Class, 2023 Mercedes-Benz S-Class, 2022 Mercedes-Benz S-Class, 2021 Mercedes-Benz S-Class, 2020 Mercedes-Benz S-Class, 2019 Mercedes-Benz S-Class, 2018 Mercedes-Benz S-Class, 2017 Mercedes-Benz S-Class, 2016 Mercedes-Benz S-Class, 2026 Mercedes-Benz SL-Class, 2025 Mercedes-Benz SL-Class, 2024 Mercedes-Benz SL-Class, 2023 Mercedes-Benz SL-Class, 2022 Mercedes-Benz SL-Class, 2020 Mercedes-Benz SL-Class, 2019 Mercedes-Benz SL-Class, 2018 Mercedes-Benz SL-Class, 2017 Mercedes-Benz SL-Class, 2016 Mercedes-Benz SL-Class.
Also filed against model years this site has no page for: 2024 Mercedes-Benz AMG C63 S E; 2024 Mercedes-Benz AMG C63 S E 4MATIC+; 2020 Mercedes-Benz AMG GT43; 2022 Mercedes-Benz AMG GT63; 2022 Mercedes-Benz AMG GT63 S; 2024 Mercedes-Benz AMG GT63 S E; 2024 Mercedes-Benz AMG GT63 S E Performance; 2026 Mercedes-Benz AMG GT63 S E Performance 4MATIC+; 2023 Mercedes-Benz AMG S 63 E 4MATIC+; 2024 Mercedes-Benz AMG S 63 E 4MATIC+; 2026 Mercedes-Benz AMG S 63 E 4MATIC+; 2024 Mercedes-Benz AMG SL63 S E; 2018 Mercedes-Benz E 400 4MATIC Cabriolet; 2018 Mercedes-Benz E 400 4MATIC Wagon; 2019 Mercedes-Benz E 450 4MATIC Cabriolet; 2020 Mercedes-Benz E 450 4MATIC Cabriolet; 2019 Mercedes-Benz E 450 4MATIC Wagon; 2020 Mercedes-Benz E 450 4MATIC Wagon; 2026 Mercedes-Benz E 53 4MATIC+; 2026 Mercedes-Benz E53 E 4MATIC+ ALL-Terrain; 2017 Mercedes-Benz GL450; 2017 Mercedes-Benz GL550; 2024 Mercedes-Benz Redundant EQE 350; 2023 Mercedes-Benz Redundant EQE 350 4MATIC; 2023 Mercedes-Benz Redundant EQS 450; 2024 Mercedes-Benz Redundant EQS 450.
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 96 model years this bulletin names have filed 3,611 complaints with NHTSA since 2015. 37 of them name Wheels, Suspension — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
I drive 40-50 miles per day in this vehicle. I noticed a wobble develop last week, so I stopped into a local service shop to see if maybe a tire weight fell off. They brought me into the garage and spun all four tires individually in front of me...Every one of them was no longer a circle, more oval shaped. All four rims lost their shape.
2019 Mercedes-Benz C-Class · Wheels · filed with NHTSA Dec 20, 2022 · ODI 11498249
I bought this 2018 e43 amg at 24k miles ,still under warranty ,and when I first told by dealer that there's a crack on my wheel I have to replace it ,I thought it was my driving even though I can't think of getting in a pothole whatsoever,so I shop around and found a random shop ,they showed me a picture of the exact same car of same…
2018 Mercedes-Benz E-Class · Wheels · filed with NHTSA Oct 8, 2021 · ODI 11436103
Mercedes-Benz S580 equipped with 21-inch wheels has experienced numerous tire blowouts over the course of ownership — too many to count. The blowouts occurred during normal driving on typical roads. Several blowouts caused rim damage and created a dangerous situation, including moments where I nearly lost control of the vehicle.
2022 Mercedes-Benz S-Class · Suspension · filed with NHTSA Dec 7, 2025 · ODI 11703501
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the suspension
Source: same model, same component group21 other manufacturer communications filed against these Mercedes-Benz models under the same component group (suspension), newest first. The eight newest are listed; the rest are on the Mercedes-Benz list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| LI35.31-P-080609 | Service bulletin | Jun 13, 2026 | Complaint Consistent popping sound from rear of vehicle. AND Rear subframe manufactured on or after November 2025. Cause Under determination… |
| LI32.34-P-080645 | Service bulletin | Jun 12, 2026 | Complaint Rattle or clunking noise from underneath the vehicle when driving over uneven/bumpy surfaces. Cause Internal tolerances of the ele… |
| LI35.10-P-078931 | Service bulletin | May 13, 2026 | Complaint Potential corrosion on the rear axle carrier Cause Due to market-specific conditions such as moisture, ingress of dirt and/or envi… |
| LI32.35-P-079752 | Service bulletin | Feb 13, 2026 | Complaint Shock symbol in instrument cluster with "Do Not Drive Over 50MPH" message AND DTC's in A108/2 or A108/3: U013281 - Communication w… |
| LI32.35-P-079965 | Service bulletin | Feb 9, 2026 | Complaint Model Year 2019-2022 167 (GLE/GLS) - Instrument Cluster Message for Suspension "Do Not Drive Over 50MPH" with or without Illuminat… |
| LI32.34-P-080258 | Service bulletin | Feb 9, 2026 | Complaint "Do Not Drive Over 50MPH" Suspension Message in Instrument Cluster Possible DTC's in Quicktest: C128763 in N51/1 - "The pressure c… |
| LI32.25-P-079706 | Service bulletin | Jan 30, 2026 | Complaint: Clattering noise from area of hood with steel suspension. Cause: Missing helical spring shim… |
| LI46.80-P-080054 | Service bulletin | Dec 6, 2025 | Complaint An instrument cluster message "Rear axle steering fault, stop immediately" is very briefly illuminated in the instrument cluster u… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Mercedes-Benz, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Mercedes-Benz LI33.20-P-078406 a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the LI33.20-P-078406 repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way. Every Mercedes-Benz warranty extension on file lists the ones Mercedes-Benz has filed.
Which vehicles does LI33.20-P-078406 cover?
The manufacturer filed it against 122 model years: 2026 Mercedes-Benz AMG GT, 2025 Mercedes-Benz AMG GT, 2024 Mercedes-Benz AMG GT, 2023 Mercedes-Benz AMG GT, 2022 Mercedes-Benz AMG GT, 2021 Mercedes-Benz AMG GT and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.