Removal and installation front brake pads (BMW 5 Series E34)

Removal

Remove the decorative wheel cap. Loosen the wheel bolts with the vehicle on the ground.



Mark the position of the wheel rims on the front wheel hubs with paint. This will ensure that the balanced wheel is set to the same position later.

Raise the front of the car.

Remove the wheel.

Caution: Do not swap the brake pads from the inside to the outside and vice versa, or the right wheel to the outside and vice versa. Swapping may cause uneven braking. Always replace all front brake pads at the same time, even if only one pad has reached the wear limit. When reinstalling brake pads, they must be marked when removed.

On the left wheel brake caliper, remove the wear sensor connector "arrow", but do not pull on the wire.





Use a screwdriver to press out the plastic caps of the mounting bolts.



Loosen both mounting bolts using a 7 mm open-end wrench.



Press the bracket with a screwdriver.



Remove the floating caliper.



Remove the outer brake shoe.



The inner brake shoe is secured to the piston by spring "6". Pull out the brake shoe.



Disconnect wear sensor 7 from the left side of the inner brake shoe.

If the insulation of the contact board is worn out, the wire insulation is damaged or the plastic part is worn out, replace the wear sensor.

Installation

Caution: When the brake pads are removed, do not press the brake pedal, as this will cause the piston to come out of the housing.

Clean the guide surfaces and the brake shoe seating areas in the housing shaft with a suitable soft metal brush or a cloth soaked in alcohol. Do not use mineral-containing substances or sharp tools.



Before installation, check the brake disc with your fingers for scratches. Scratched discs should be replaced. Before installing new brake pads, clean brake discs with a gray or bluish coating.

Measure the thickness of the brake disc.

Check the integrity of the piston dust cap 2 (Figure W - 4467). Replace a damaged cap immediately, as penetrating dirt quickly leads to brake caliper leaks. This requires removing and disassembling the brake caliper (work at a service station).



Press the brake piston 2 with a pressing device. This can also be done with a wooden rod (hammer handle), but at the same time, be especially careful to ensure that the piston is not tilted and that the anti-skid cap is not damaged.

Note: When the pistons are pressed, brake fluid is squeezed out of the brake cylinders into the expansion tank. Monitor the fluid level in the tank; it may be necessary to suck out the fluid.

To suck out the fluid, you can use a vessel used to release air from the brake system or any plastic bottle that is intended only for brake fluid. Do not use beverage bottles! Brake fluid is poisonous and should never be sucked out by mouth through a hose. Use a suction device. After replacing the pads, the brake fluid level should also not exceed the MAX mark, since the liquid expands when the temperature rises. Leaking brake fluid gets on the master brake cylinder, destroys the paint and causes corrosion.

Note: If the brake pads are heavily worn, check the ease of piston movement. If the piston moves with difficulty, send the caliper for repair (work at a service station).

To prevent disc brakes from squeaking, apply a thin layer of grease (for example, Plastitube, Tunap VC 582/S, Chevron SRJ/2, Liqui Moly LM-36 or LM-508-ASC) on the back side of the brake pads. In this case, the lubricant is applied only to the back side. Under no circumstances should the lubricant get on the working surface of the brake pad or on the brake disc. If necessary, wipe off the lubricant and wash the surface with alcohol.



Insert the brake shoe with spring 6 into the piston.



Secure wear indicator 7 to the inner brake shoe. Ensure correct position of retaining clip 8.





Insert the outer brake shoe 9 into the brake caliper and place the brake caliper on the brake disc.



Inspect the 2 brake caliper mounting bolts and clean the bolt threads if necessary. The threads in the brake bracket can be cleaned by running a tap through them. Replace bolts with damaged or rusted threads. Tighten the bolts with a 7 mm open-end wrench to a tightening torque of 30 Nm

Caution: Do not overtighten the bolts.

Place protective caps on the bolts.



Connect the wear sensor connector on the left side of the vehicle to the connector on the brake caliper. The wire should pass through the loop of the bleed valve cover, see the picture.



Insert the bracket into the brake caliper.

Apply 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.

Install the wheel hub cap.

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

Check the brake fluid level in the expansion tank and, if necessary, top up the fluid to the MAX mark.

Carefully allow the new brake pads to break in by lightly pressing the brake pedal several times to brake the car from 80 km/h to 40 km/h. Allow the brakes to cool between successive brakings.

Attention: During the first 200 km of travel, avoid sudden braking until the vehicle comes to a complete stop.