Withdrawal
Mark the position of the rear wheels in relation to the hubs with paint. Thanks to the atom, a balanced wheel can be set to its original position. When loosening the wheel bolts, the vehicle must be on its wheels. Raise the car from behind and remove the rear wheels.
Attention: If the brake linings are to be reinstalled, their location must be marked before removal. It is not allowed to replace the brake linings of the right wheel with the linings of the left wheel. Changing the location of the pads can lead to uneven braking action. Be sure to use only original BMW brake linings or brake linings destroyed by the company. Brake linings must be replaced only as a set and at the same time for all axle wheels, even if only one lining has reached the wear limit.
Disconnect the plug -arrow- of the brake pad wear indicator sensor on the right disc brake caliper with your fingers, do not pull on the wire.
Press off plastic caps -1- and unscrew both caliper fixing bolts -2- located under the caps.
Press the retaining spring with a screwdriver.
Pull out the caliper towards the rear.
Remove outer brake lining.
The inner brake lining is secured by a spring -6- to the piston of the brake cylinder. Remove the brake lining.
Installation
Attention: When the brake pads are removed, do not squeeze out the carrion of the brake, otherwise the piston will be pushed out of the caliper body.
Boil the brake lining wear sensor. If the insulation of the contact plate is frayed, the wire insulation is damaged, or the plastic part is ground off, then lure the wear sensor.
Clean the guide surfaces and pads in the pads with a suitable soft metal shank or wipe with a cloth soaked in alcohol. Do not use solutions containing mineral oils or sharp-edged tools. If old brake linings are installed, they should also be cleaned.
Before installing the pads, examine the brake discs to the touch with your fingers for the absence of recesses. Notched discs must be replaced with new ones. Discs with a gray or blue color should be cleaned before installing new brake linings.
Measure the thickness of the brake discs.
Check dust cap -2- of brake piston for cracks. Immediately lure damaged caps, as penetrating dirt will quickly break the tightness of the caliper. In this case, the caliper must be removed and disassembled (workshop work).
Bring the piston of the brake cylinder back into the cylinder with a return tool. You can also use a hardwood rod for this (hammer handle), however, care must be taken to ensure that the piston is not warped and that the piston surfaces and dust cap are not damaged.
Attention: When installing the piston in the cylinder, the brake fluid is squeezed out of the brake cylinder into the compensation tank. Monitor the fluid level in the tank and, if necessary, suck out excess fluid with a siphon.
For suction, use a bottle that was used to remove air from the hydraulic system, or a plastic bottle that previously only came into contact with brake fluid. Do not use bottles intended for drinking liquids! Brake fluid is poisonous and must never be sucked out by mouth through a hose. Use a siphon. After replacing the brake linings, the level of the brake fluid in the compensation tank must also not exceed the MAX mark, since the fluid expands when heated. The brake fluid flowing out of the reservoir gets under the main brake cylinder, destroys the varnish coating and leads to corrosion.
Attention: If the brake linings are heavily worn, check that the piston can move freely. To do this, insert a wooden rod into the caliper and ask an assistant to slowly depress the brake pedal. The piston should move easily in both directions. During the check, another caliper must be installed. Make sure the piston is not pushed out of the caliper. If the piston stroke is heavy, the caliper must be repaired (workshop work).
To prevent disc brakes from squealing, the reverse sides of the brake pads. as well as the side surfaces of their back side, finely treat with grease (e.g. Plastiluba, Tunap VC 5B2/S, Chevron SRJ/2, Liqui Moly LM-36 or LM-50B-ASC).
To prevent squealing disc brakes, lightly lubricate (e.g. Plastilube, Tunap VC 5B2/S, Chavron SRJ/2, Liqui Moly LM-36 or LM-50B-ASC) named below the surface.
The contact surfaces of the piston to the brake lining.
Clean contact surfaces -3- of caliper and finely coat shaded areas -illustration- with anti-squealing grease.
Clean the caliper holders of the rectangular guide heads and finely coat the shaded areas with anti-squealing grease -illustration-.
Caution: Grease must never get on the dust seals, brake linings and brake discs. If grease gets in, it should be wiped off immediately, the recessions should be removed with a rag soaked in alcohol, or the dust cuffs should be replaced.
Caution: Do not lubricate the reverse side of the brake lining.
Insert the brake lining with the spring into the piston.
Insert the outer brake lining -9- into the caliper and slide it onto the brake disc. Make sure that the brake linings fit well in the guides.
Perform a visual inspection of the two caliper fixing bolts, if necessary, clean the threads from dirt. If necessary, clean the threaded holes in the brake shield with a tap. Bolts with poor threads or rust build-ups should be replaced with new ones. Tighten bolts -7- with a 7 mm hexagon wrench -6- to 30 Nm.
Attention: Bolts should only be cleaned, not lubricated.
Insert protective caps into both bolt holes.
Connect the pad wear indicator plug on the right side of the vehicle. Lay the connecting wire in the loop of the valve cap to remove air.
Insert the retaining spring into the caliper.
Screw on the rear wheels. Do not grease wheel bolts. Attach the wheel so that the marks applied before removal coincide. Lower vehicle, tighten wheel bolts crosswise to 100 Nm.
Caution: Depress the brake pedal strongly repeatedly until strong resistance is felt. In this case, the brake linings are applied to the discs and occupy a position that meets the operating conditions.
Check the brake fluid level in the compensation tank and, if necessary, top up the level to the MAX mark.
Attention. Run a security compliance check:
- Are the brake lines tight?
- Are the brake hoses in the holder?
- Are the air bleed valves tight?
- Is there enough fluid in the brake system?
- With the engine running, perform a leak test. To do this, act on the brake carrion with a force of 200 to 300 N for about 10 seconds (from 20 to 30 kg). Do not release the brake pedal. Check all connections for tightness.
Carefully run in new brake linings by repeatedly braking the vehicle from a speed of 80 km/h to 40 km/h by lightly depressing the brake pedal. Allow the brakes to cool down between braking.
Attention: On a distance of up to 200 km, braking to a complete stop should not be undertaken.
Note: Brake linings must be disposed of as special waste. Local authorities must inform if disposal is allowed through regular household waste collection points.