Recommended replacement interval for the part category Brake pad wear sensor : 30000 km

Important!

This replacement procedure can be used for:
MERCEDES-BENZ SLK (R172) 200 (172.434), MERCEDES-BENZ SLK (R172) 300 (172.438), MERCEDES-BENZ SLK (R172) 250 CDI / d (172.403), MERCEDES-BENZ SLK (R172) 55 AMG (172.475), MERCEDES-BENZ SLK (R172) 350 (172.457), MERCEDES-BENZ SLK (R172) 200 (172.448), MERCEDES-BENZ SLK (R172) 250 (172.447) … View more

The steps may slightly vary depending on the car design.

This video shows the replacement procedure of a similar car part on another vehicle

All the parts you need to replace – Brake Pad Wear Sensor for SLK (R172) and other MERCEDES-BENZ models

Brake pad wear sensor

        Brake pad wear sensor for SLK (R172) Petrol (204 hp)
      
        Brake pad wear sensor for SLK (R172) Petrol (184 hp)
      
        Brake pad wear sensor for SLK (R172) Petrol (306 hp)
      
        Brake pad wear sensor for SLK (R172) Petrol (422 hp)
      
        Brake pad wear sensor for SLK (R172) Diesel (204 hp)
      
        Brake pad wear sensor for SLK (R172) Petrol (245 hp)
      
        Brake pad wear sensor for SLK (R172) Petrol (184 hp)

Replacement: brake pad wear sensor – MERCEDES-BENZ SLK (R172). Tools you need:

                        Wire brush
                      
                        Nylon cleaning brush
                      
                        WD-40 spray
                      
                        Electronic spray
                      
                        Brake cleaner 
                      
                        Anti-squeal paste
                      
                        Ceramic grease
                      
                        Torque wrench
                      
                        Torx bit E10
                      
                        HEX bit no.H7
                      
                        Wheel impact socket #17
                      
                        Ratchet wrench
                      
                        Long nose pliers
                      
                        Brake caliper wind back tool
                      
                        Crow bar
                      
                        Wheel chock

Buy tools

Replacement: brake pad wear sensor – MERCEDES-BENZ SLK (R172). AUTODOC recommends:

The replacement procedure is identical for both brake pad wear sensors on the same axle.
The wear sensors should be replaced together with the brake pads.
Please note: all work on the car – MERCEDES-BENZ SLK (R172) – should be done with the engine switched off.

Carry out replacement in the following order:

Step 1

Open the bonnet. Unscrew the brake fluid reservoir cap.

Step 2

Secure the wheels with chocks.

Step 3

Loosen the wheel mounting bolts. Use wheel impact socket #17.
Step 4

Raise the car.

Replacement: brake pad wear sensor – MERCEDES-BENZ SLK (R172). Tip from AUTODOC:
If you are using a jack, make sure it rests on a flat surface without any unevenness.Be sure to additionally secure the car with jack stands.
Step 5

Unscrew the wheel bolts.

AUTODOC recommends:
Warning! To avoid injury, hold the wheel while unscrewing the fastening bolts. MERCEDES-BENZ SLK (R172)
Step 6

Remove the wheel.
Step 7

Detach the connector of the brake pad wear sensor. Use long nose pliers.
Step 8

Clean the fasteners of the brake pad wear sensor wiring harness. Use a wire brush. Use WD-40 spray.
Step 9

Unscrew the fasteners of the brake pad wear sensor wiring harness. Use Torx E10. Use a ratchet wrench.
Step 10

Remove the fastening bolt.
Step 11

Detach the brake pad wear sensor wiring harness.
Step 12

Detach the brake caliper retaining spring. Use a crowbar.
Step 13

Remove the dust boot caps of the brake caliper guide pins. Use a crowbar.
Step 14

Unscrew the brake caliper fasteners. Use HEX No.H7. Use a ratchet wrench.
Step 15

Spread the brake pads. Use a crowbar.
Step 16

Remove the brake caliper.

Replacement: brake pad wear sensor – MERCEDES-BENZ SLK (R172). Tip:
Tie the caliper to the suspension or to the body with a wire without disconnecting from the brake hose to prevent depressurization of the brake system.Make sure that the brake caliper is not hanging on the brake hose.Don't press the brake pedal after the brake caliper has been removed. As a result, the piston can fall out from the brake cylinder, and brake fluid leakage and depressurization of the system may occur.
Step 17

Remove the brake pads.
Step 18

Clean the brake caliper bracket from dirt and dust. Use a wire brush. Use a brake cleaner.

AUTODOC recommends:
After applying the spray, wait a few minutes.Check the brake caliper bracket, brake caliper guide pins and boots. Clean them. Replace, if necessary.
Step 19

Treat the brake caliper piston. Use a nylon cleaning brush. Use a brake cleaner.

AUTODOC recommends:
Replacement: brake pad wear sensor – MERCEDES-BENZ SLK (R172). After applying the spray, wait a few minutes.Check the brake caliper bracket, brake caliper guide pins and boots. Clean them. Replace, if necessary.
Step 20

Press in the brake caliper piston. Use brake caliper wind back tool.
Step 21

Attach the new wear sensor to the new pad.
Step 22

Treat the brake pads in the area where their surface comes into contact with the brake caliper bracket. Use anti-squeal paste.

AUTODOC recommends:
Make sure the disc surface is clean before installing the pads.
Step 23

Install the brake pads.
Step 24

Install the brake caliper and fix it.
Step 25

Tighten the brake caliper fasteners. Use HEX No.H7. Use a torque wrench. Tighten it to 25 Nm torque.
Step 26

Install the dust boot caps of the brake caliper guide pins.
Step 27

Attach the brake pad wear sensor wiring harness.
Step 28

Install the fastening bolt.
Step 29

Tighten the fasteners of the brake pad wear sensor wiring harness. Use Torx E10. Use a torque wrench. Tighten it to 8 Nm torque.
Step 30

Treat the brake pad wear sensor plug. Use dielectric grease.
Step 31

Attach the connector of the brake pad wear sensor.
Step 32

Install the brake caliper retaining spring.
Step 33

Clean the wheel rim mounting seat. Use a wire brush.
Step 34

Treat the surface where the brake disc contacts the wheel rim. Use ceramic grease.
Step 35

Clean the brake disk surface. Use a brake cleaner.

AUTODOC recommends:
After applying the spray, wait a few minutes.
Step 36

Install the wheel.

AUTODOC recommends:
Important! Hold the wheel while screwing in the fastening bolts. MERCEDES-BENZ SLK (R172)
Step 37

Screw in the wheel bolts. Use wheel impact socket #17.
Step 38

Lower the car and working in a cross order, tighten the wheel bolts. Use wheel impact socket #17. Use a torque wrench. Tighten it to 130 Nm torque.
Step 39

Remove the jacks and chocks.

AUTODOC recommends:
Without starting the engine, press the brake pedal several times until you feel significant resistance.Check the brake fluid level in the expansion tank and refill if necessary.
Step 40

Tighten the brake fluid reservoir cap. Close the hood.

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