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Manufacturer communication · Service campaign

BMW service campaign 0034200300

What it saysThere may be an internal leakage in the brake fluid expansion tank (aka brake fluid reservoir). NHTSA’s full summary ↓

BMW filed this with NHTSA as a service campaign dated Jul 30, 2025, received Jul 31, 2025, about the service brakes — 1 document under this number: B340925. It names 3 model years (2024). A service campaign is not a safety recall — there is no NHTSA campaign number and no federal requirement — but it is usually work the manufacturer pays for on the vehicles it names; the dealer checks the VIN against the manufacturer’s list.

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What the bulletin says

Source: NHTSA's summary of the manufacturer's communication

There may be an internal leakage in the brake fluid expansion tank (aka brake fluid reservoir). In the rare case of a leak, the filling level sensor might malfunction over a relatively long period of time.

Manufacturer campaign id 0034200300 Kind Service campaign Manufacturer date Jul 30, 2025 Received by NHTSA Jul 31, 2025 Components Service Brakes

Document filed under this number

DocumentKindDatedNHTSA idAt NHTSA
B340925Service campaignJul 30, 202511021109PDF, 241 KB

What the document itself lists

Parts the bulletin names

Part numberDescriptionQty
34 51 9 504 021Expansion tank1
07 11 9 905 147Hex bolt with washer (M10x25-10.9ZNS3)4
07 14 7 483 888Hex bolt4
07 14 8 086 257Hex bolt (M10x35)4
07 14 9 502 134Multi-purpose bolt2
51 61 8 084 883Hex bolt (M10x70)4

Labour operation and the time the manufacturer allows

OperationDescriptionTime
00 78 713Additional work with fixed caliper for inaccessible rim designs2 FRU

Read by machine from the document NHTSA serves (5 pages), read Sep 30, 2026. A part number is shown only where it matches BMW’s own catalogue shape, an operation only with its code and time, and a description only where the reader got it whole; anything it could not settle is left out, and the PDF is the record. Times are the manufacturer’s warranty allowances, not a quote.

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 them

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 database

Owners of the 3 model years this bulletin names have filed 17 complaints with NHTSA since 2015. 2 of them name Service Brakes — 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.

Yesterday 4pm try to park my car at infront of grage door i have been slow down with touch break pedal. But this car won't stop at all so this car hit home grage door and and side stone decorations

2024 BMW 3 Series · Service Brakes · filed with NHTSA Nov 19, 2025 · ODI 11700260

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 service brakes

Source: same model, same component group

12 other manufacturer communications filed against these BMW models under the same component group (service brakes), newest first. The eight newest are listed; the rest are on the BMW list.

NumberKindDatedNHTSA’s summary
0034410300Service campaignAug 27, 2026The protective film which covers the 6 threaded connection holes on the DSC hydro unit may not have been completely removed before the brake…
B320426Service campaignJul 23, 2026Hydro Unit DSC
B062826OtherApr 24, 2026Brake Hose Return
B340925Service bulletinDec 17, 2025There may be an internal leakage in the brake fluid expansion tank (aka brake fluid reservoir). In the rarecase of a leak, the filling level…
B064725OtherSep 9, 2025Protection Plate Return
B341025Service bulletinJul 14, 2025After programming from the I-Levels between …24-03-505 and lower than …24-03-540 to I-Level …24-11-530 or higher, the following CCM may be d…
B340625Service bulletinMay 2, 2025Brake “groaning” noises heard at the rear axle at slow speeds, i.e. close to standstill, stop and go driving;when parking or maneuvering.
B340225Service campaignApr 3, 2025Due to a manufacturing defect, there might be an internal leakage of the brake fluid expansion tank. In therare case that there is a leakage…

Quote the number at the service desk. It is what the dealer’s system is keyed on.

Every manufacturer communication NHTSA holds for BMW, by the number printed on the letter.

Photo: Christian Buehner / Unsplash

Common questions

Source: NHTSA, 49 CFR 579.5

Is BMW 0034200300 a recall?

No. A service campaign 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 0034200300 repair free?

A service campaign is usually paid by the manufacturer on the vehicles it names, within the terms and time limit the document sets; the dealer checks the VIN against the manufacturer’s list.

Which vehicles does 0034200300 cover?

The manufacturer filed it against 3 model years: 2024 BMW 3 Series, 2024 BMW 4 Series, 2024 BMW M. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.