2025 BMW 3/4 Series Brake Fluid Expansion Tank

Important Warnings for Owners and Dealers

BMW has issued a critical advisory regarding vehicles affected by this Delivery Stop. Dealers are instructed:

• "Do not deliver to a customer, a New, Certified Pre-Owned or Used vehicle subject to a Delivery Stop, until the vehicle is repaired."
• "Do not use or sell replacement equipment/parts subject to a Delivery Stop."

This means that any new, certified pre-owned, or used 2025 BMW 3/4 Series brake fluid expansion tank affected by this issue cannot be sold or delivered until the necessary repair has been completed.

Symptoms

Owners of affected 2025 BMW 3/4 Series and M models may experience issues related to an internal leakage within the brake fluid expansion tank. In some cases, this leakage could lead to the "filling level sensor might malfunction over a relatively long period of time."

Cause of the Issue

The root cause of this problem has been identified as a manufacturing defect in the brake fluid expansion tank itself.

Repair Procedure Summary

The recommended correction for this issue is to replace the brake fluid expansion tank. The repair procedure, identified as REP34 51 110, involves removing and installing a new expansion tank for the integrated braking system. It is crucial that the removed parts are retained for further analysis by BMW.

Required Tools or Parts

To perform this repair, the following parts are specified:

• Expansion Tank: 34 51 9 504 021 (Quantity: 1)
• Hex Bolts (G2x models): 07 11 9 905 147 (x4), 07 14 7 483 888 (x4)
• Hex Bolts (G8x models): 07 14 8 086 257 (x4), 07 14 5 B42 409 (x4)
• Hex Bolts (G87 models): 07 14 8 086 257 (x4), 51 61 8 084 883 (x4)
• Brake Fluid DOT 4:
  • 81 22 0142156 (12 oz bottle)
  • 81 22 0142155 (1 Gallon)
  • 81 22 5B43922 (1/10-liter billing part number for 30-liter drum)
• BMW Group Non-Chlorinated Brake Parts Cleaner:
  • 83 19 5A53089 (3% VOC, 15 oz)
  • 83 19 2451315 (45% VOC, 15 oz)

Additional materials and small parts, such as fluids, lubricants, one-time use screws, nuts, and seals, may be required and should be selected according to BMW's repair instructions.

Owner Action

If you own a 2025 BMW 430i, 330i, or M240i, and believe your vehicle may be affected by this Delivery Stop SIB 34 02 25, you should contact your authorized BMW dealer. The repair will be performed free of charge under the terms of the Delivery Stop. Dealers can check your vehicle's status in the Inventory Campaign Details (ICD) under ROSS. BMW also provides for Alternative Mobility Solution (AMS) expense reimbursement for owners, with further details available by referencing SI B01 29 16.