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Home >> BMW >> 2018 >> X3 M40i >> Repair and Diagnosis >> External Pages >> Different car >> Section 464 (Brakes - Repair) >> Rear Brakes >> 34 21 320 Removing and installing or replacing both rear brake discs

34 21 320 Removing and installing or replacing both rear brake discs

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Special tools required: 

Necessary preliminary tasks: 

After completing repair work:

Check minimum brake disc thickness:

NOTE: If the brake discs are replaced, you must also fit new brake pads.

Always replace brake discs in pairs.

Fig 1: Checking Minimum Brake Disc Thickness
G09849601Courtesy of BMW OF NORTH AMERICA, INC.
IMPORTANT: New brake pads may only be fitted if the brake disc thickness is greater than the MINIMUM BRAKE DISC THICKNESS (MIN TH).

Release screws (1). Detach brake-caliper support.

Installation note: 

Tightening torque 34 21 2AZ .

Fig 2: Identifying Brake Caliper Support Screws
G06889981Courtesy of BMW OF NORTH AMERICA, INC.
IMPORTANT: To release brake disc: Do not under any circumstances strike friction ring with a hammer or similar!
If necessary, carefully tap on base of brake disc chamber with a rubber mallet.
Clean contact surface of brake disc at wheel hub thoroughly and remove traces of corrosion.
Unevenness on contact surface may result in distortion of brake disc!

Release screw (1) and remove brake disc (2).

Installation note: 

Replace screw.

Tightening torque 34 21 1AZ .

Fig 3: Identifying Brake Disc And Screw
G09849685Courtesy of BMW OF NORTH AMERICA, INC.