BMW 34211101760 Wheel Brake Cylinder

Remove the cylinder and brush away all external dirt. Take out the two rubber boots and extract the internal components; if the pistons are stuck, apply air pressure to the fluid inlet hole while ensuring the bleed screw is refitted and closed. Wash all components in hydraulic fluid or methylated spirit, examining the surfaces of the pistons and cylinder bores for any scoring, scratching, or 'bright' wear areas, and if any are found, renew the wheel cylinder completely. If the pistons and cylinder are in good condition, discard the old seals and boots and obtain a repair kit. Fit the new seals using only your fingers to manipulate them into position, and dip the pistons in clean fluid before assembling.

Jack up the rear of the car and remove the road wheel and the brake drum. Turn the shoe adjusters to their maximum adjustment position. To minimize loss of hydraulic fluid, place a piece of plastic sheeting under the fluid reservoir cap and screw the cap on tightly. Disconnect the fluid inlet pipe from the wheel cylinder, then unscrew the bleed screw and the cylinder securing bolts. Prise the upper ends of the brake shoes slightly apart and withdraw the wheel cylinder. Refitting is a reversal of removal, but adjust the shoes and after removing the plastic sheeting, bleed the hydraulic system.