Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Remove and install or replace battery (Except M4 Convertible)
To ensure the correct safety and convenience functions, install only the original battery (battery size and type) stored in the vehicle order. OBSERVE NOTE ON BATTERY REPLACEMENT .
Necessary preliminary work:
- Clamp off BATTERY LEAD FROM NEGATIVE CONNECTION POINT .
Removal:
Fold up cover (1) on safety battery terminal (2).
Loosen nut (3).
Tightening torque 61 21 1AZ .
Do not under any circumstances pull/lever off safety battery terminal (2) by force.
Pull off safety battery terminal (2) towards top, lay to one side and secure.
Release screws (1) and remove retaining bracket (2).
Unlock connector (3) and disconnect.
Pull vent hose (3) off the battery (5).
Release screw (1) and remove with holder (2).
Remove battery.
Installation:
Join battery.
Join holder (2) and tighten with screw (1).
Tightening torque 61 21 5AZ .
Installation note:
Make sure battery is correctly fitted in fixture.
Insert retaining bracket (2) and tighten with screws (1).
Tightening torque 61 21 5AZ .
Connect connector (3) to battery (5).
Connect vent hose (4) to battery (5).
Installation note:
The battery has two vent holes:
- One vent hole (1) must be closed correctly with a dummy plug.
- The vent hose (3) must be connected correctly at the other vent hole (2).
Always install the vent hose (3) with a downhill gradient to the outside!
No siphon formation!
Attach the safety battery terminal (3) on the positive battery terminal.
Tighten the nut (2).
Tightening torque 61 21 1AZ .
Close cover (1) on safety battery terminal (3).
Replacement:
Required follow-up work:
- Connect BATTERY CABLE NEGATIVE TERMINAL .
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.