15. REAR WHEEL/REAR BRAKE/ REAR SUSPENSION Downtown 300i ABS Remove the piston from the brake caliper. Compressed Air If necessary, use compressed air to squeeze out the piston through the brake fluid inlet opening and place a towel under the caliper to avoid contamination caused by the removed piston. Check the piston cylinder for scratches or wear and replace if necessary. Check the caliper cylinder for scratches or wear and measure the cylinder bore. ASSEMBLY Install the two spring plates onto the groove of the caliper. 15-4