Inspect condition of brake disks

AP42.10-P-4258V

Inspect condition of brake disks

08.05.2017

Model

171, 172

Modification notes

22.01.2016

Brake disk thickness

Model 172.466/475

BE42.10-P-1001-09D

Model 171 shown

 Warning

Risk of injury. Skin or eye injuries may result when handling hot or glowing objects.

Wear protective gloves, protective clothing and safety glasses, if necessary.

AS00.00-Z-0002-01A

Topical note

Notes on repairs to brake system

AH42.00-P-0003-01A



Remove

1

Remove wheel-and-tire assembly

AP40.10-P-4050V



Check

2

Check brake disks (1) on front and rear axle for score marks and cracks

 Cracks can occur due to high stress.

 Brake disks (1) do not have to be replaced when the crack length (2) is a maximum of 25 mm. With perforated brake disks or those provided with sunk holes (1) measure the crack length (2) including the bore diameter.

For cracks and scores which have split open and are deeper than 0.5 mm:



Replace brake disks (1) subject to separate repair order.



Measure

3

Measure thickness of brake disks on front and rear axles using caliper gauge (010)

Check values for front axle brake disksBrake disk thickness

*BE42.10-P-1001-08D

Check values for rear axle brake disksBrake disk thickness

*BE42.10-P-1001-09D

 Caliper gauge

*140589001900

Observe recommended limit dimensions. If the wear limit has been exceeded or will be exceeded before the next brake pad change:



Replace brake disks (1) subject to separate repair order.



Install

4

Mount wheel and tire assembly

AP40.10-P-4050V

Check values for front axle brake disks

Number

Designation

Model 171.442

Model 171.445/454/456

BE42.10-P-1001-08D

Brake disk thickness

New

mm

25

28

Wear limit

mm

22,4

25,4

Check values for front axle brake disks

Number

Designation

Model 171.473

Model 171.458

BE42.10-P-1001-08D

Brake disk thickness

New

mm

32

28

Wear limit

mm

30

26

Check values for front axle brake disks

Number

Designation

Model 172.403/404
except code 950 (AMG Sports package)
except code 952 (Sports package)
Model 172.434/435/438
except code 950 (AMG Sports package)
except code 951 (Sports package USA)
except code 952 (Sports package)
Model 172.447
except code 494 (US version)
except code 950 (AMG Sports package)
except code 951 (Sports package USA)
except code 952 (Sports package)
except code P88 (Edition 1)

Model 172.403/431/434/435/438/447/448
with code 950 (AMG Sports package)
Model 172.403/431/434/435/438/447/448
with code 952 (Sports package)
Model 172.431/434/435/438/447/448
with code 951 (Sports package USA)
Model 172.447/448
with code P88 (Edition 1)
Model 172.457

BE42.10-P-1001-08D

Brake disk thickness

New

mm

32

32

Wear limit

mm

29,4

30

Check values for front axle brake disks

Number

Designation

Model 172.404
with code 950 (AMG Sports package)
Model 172.404
with code 952 (Sports package)
Model 172.431
except code 950 (AMG Sports package)
except code 951 (Sports package USA)
except code 952 (Sports package)
Model 172.447
with code 494 (US version)
Model 172.448
except code 494 (US version)
except code 950 (AMG Sports package)
except code 951 (Sports package USA)
except code 952 (Sports package)
except code P88 (Edition 1)
Model 172.448
with code 494 (US version)

Model 172.466/475

BE42.10-P-1001-08D

Brake disk thickness

New

mm

28

36

Wear limit

mm

25,4

34

Check values for rear axle brake disks

Number

Designation

Model 171.442/445
except code 952 (Sports package)

Model 171.442/445
with code 952 (Sports package)
Model 171.454/456/458

BE42.10-P-1001-09D

Brake disk thickness

New

mm

9

10

Wear limit

mm

7,3

8,3

Check values for rear axle brake disks

Number

Designation

Model 171.473

Model 172.403/404/431/434/435/438/447/448/457

BE42.10-P-1001-09D

Brake disk thickness

New

mm

26

10

Wear limit

mm

24

8,3

Check values for rear axle brake disks

Number

Designation

Model 172.466/475

BE42.10-P-1001-09D

Brake disk thickness

New

mm

22

Wear limit

mm

20