How to Change the Disc Brakes on a 2001 BMW 325i

The BMW 3-series arrived in the U.S. in 1977 as the replacement for the 2002, after a two-year stint in the European market only. In 1984, the 325e came to be and BMW released the 325i three years later. The 2001 BMW 325i came fitted with four-wheel disc brakes, just as any car dubbed the ultimate driving machine should. Replacing the front disc brakes on the 2001 325i requires a quick inspection of the rotor to determine if the rotor needs replacement as well.

Instructions

1

Loosen the front wheel bolts with a ratchet and socket, and raise the front of the BMW with a floor jack. Slide jack stands under the vehicles subframe and lower the 325i onto the jack stands. Remove the wheel bolts and pull the front wheels off the vehicle.

2

Find the metal spring on the outside of the brake caliper. Pry it away from the caliper with a flat-head screwdriver to disengage its ears from the holes in the caliper. Pull the spring off the caliper.

3

Skip to the next step if you are working on the passengers side of the vehicle, as only the drivers side has a brake pad wear sensor. Trace the brake pad wear sensor wire upward until you find where it connects to the 325is wiring harness. Press and hold the unlocking button on the wiring harness and unplug it.

4

Pull the plastic plugs from the brake caliper bolts. Remove the caliper bolts with a ratchet and hex-bit socket. Pull the caliper upward off its bracket and hang it from a nearby suspension component with a bungee strap.

5

Press one end of the outer brake pad inward to disengage its tab from the locating hole in the caliper. Pivot that side of the pad upward from the caliper. Repeat this step on the other side of the pad and remove the pad from the caliper.

6

Set a drain pan under the brake caliper. Position an 8-inch C-clamp over the caliper, so its fixed part contacts the inner brake pad and its screw part touches the rear of the caliper. Open the brake bleeder valve on the caliper with a combination wrench and immediately tighten the C-clamp until it stops moving. Immediately tighten the bleeder valve and remove the C-clamp.

7

Notate the routing of the wear sensor on the inner brake pad, if you are working on the drivers side. Pull the inner brake pad from the caliper; notice the inner pad has metal springs that secure it in the cavity of the caliper piston.

8

Align the springs on the rear of the new inner brake pad with the cavity in the caliper piston and press the pad toward the piston until the pad sets on the piston. Route the brake pad wear sensor wire through the caliper in the same path as the old wire's routing.

9

Pry the metal spring on the rear of the outer brake pad with a flat-head screwdriver and guide that side onto the caliper. Slide that side of the pad onto the caliper until the tab seats in the locating hole in the caliper. Repeat this step on the other side of the brake pad.

10

Remove the rotor retaining screw with a ratchet and hex-bit socket. Pull the rotor off the hub and inspect it for any defects, including deep grooves, evidence of grinding, mirror-like shine or cracks. If any defects exist, replace the rotor.

11

Set the rotor on the 325is hub and align the screw hole in the rotor with the screw hole in the hub. Hand-thread the rotor retaining screw and torque it to 12 foot-pounds with a torque wrench and hex-bit socket.

12

Set the caliper back onto its bracket and hand-thread its retaining bolts. Tighten the caliper bolts to 81 foot-pounds with a torque wrench and hex-bit socket. Slide the curved part of the metal clip between the outer part of the caliper and the center of the rotor, then press upward on the clip until the ears on the clip snap into the holes in the caliper. Route the brake pad wear sensor wire back up to its connection point to the BMWs wiring and plug it in.

13

Repeat steps 2 through 12 to replace the pads on the other side of the vehicle.

14

Reinstall the front wheel on the BMWs front hubs and hand-tighten the wheel bolts. Raise the 325i off the jack stands with a floor jack and remove the jack stands. Lower the vehicle to the ground. Tighten the wheel bolts, in a crisscross pattern, to between 82 and 96 foot-pounds with a torque wrench and socket.

15

Press and release the brake pedal until it feels firm. Check the brake fluid level in the brake master cylinder. If the fluid is below the Max line, unscrew the cap from the master cylinder and pour DOT 4 brake fluid into the master cylinder until the fluid reaches the Max line.

16

Turn the ignition to the 1 position and leave it there for at least 30 seconds to clear the brake wear light.