Removal and installation front brake discs and brake calipers (BMW 3 Series E30)

Removal

Loosen the wheel bolts.

Remove the decorative cap. Mark the position of the wheel disks on the wheel hubs with paint. Thanks to this, the balanced wheel is subsequently installed in the same position.

Raise the front of the car and remove the wheel.



Loosen the mounting bolts "1" of the brake caliper and remove the brake caliper from the brake disc.

Hang the brake caliper on the wire so that the brake hose and wear sensor wire are not stretched or twisted.

Caution: Do not unscrew the brake hose, otherwise you will have to bleed the air from the brake system.

If complete removal of the brake caliper is required, the brake hose "2" should first be unscrewed. In other cases, the brake hose does not need to be unscrewed.

Caution: Collect leaking brake fluid in a bottle intended exclusively for brake fluid. You can also pump out brake fluid from the expansion tank.

Unscrew bolt "4" with a 5 mm open-end wrench.



Remove the brake disc.

Installation

To ensure uniform braking on both sides, the surfaces of both discs must be identical in surface finish and treatment. Therefore, it is necessary to replace both discs at the same time.

The service station can check the disc runout. Maximum lateral runout (in the installed position): 0.2 mm.

Measure the thickness of the disc (see section "Checking the thickness of brake discs").

If present, remove rust from the brake disc flange and from the front wheel hub.

Remove varnish from the surface of the new disk with nitro solvent.

Place the brake disc on the wheel hub and secure with a bolt. First, turn the brake disc so that the holes for the bolt align.

Install the brake caliper with the brake pads inserted. Do not stretch or twist the brake hose. Check the freedom of movement of the brake hose when turning the steering wheel from lock to lock.

Secure the brake caliper with a bolt tightening torque of 120 Nm. Pre-coat the bolt threads with engine oil.

Caution: If the brake hose has come loose, it is necessary to bleed the brake system (see section "Bleeding the brake system").

Install the wheel observing the marking of the disk position on the hub. Lower the car and cross-tighten the wheel bolts to a torque of 110 Nm.

Caution: With the vehicle stationary, press the brake pedal several times until you feel a noticeable resistance.

Check the brake fluid level in the expansion tank, if necessary, top up the fluid to the MAX mark (see section "Checking the brake fluid level and the brake fluid level warning light").