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» User Manual - Digital Tester K154433N50
4. Checking of wear status of brake pads and disc
Note, this check is only possible for brakes having a ‘continuous‘ sensor (potentiometer) and therefore it is necessary to test if such a potentiometer is fitted:
Depending on accessibility it may be necessary to remove the wheel.
Disconnect the vehicle cable plugged into the potentiometer on the caliper.
Select the measuring cable depending on plug variant (screwed or clamped) and connect it with the tester.
Connect and fix the 3-pin plug to the potentiometer connector of the caliper.
Turn the rotary switch to position “End Wear Display black/white“.
If the tester indicates a value < 0.2V or > 4.8V then a ‘continuous‘ sensor is not installed and the wear status of brake pads and disc cannot be determined by means of the
tester. Carry out an optical check of the wear status - see the respective service manual. For detailed instructions on the necessary service steps - refer to section “Brake
Identification and Service Manuals“.
The following steps therefore assume a ‘continuous‘ wear sensor is fitted.
Turn the rotary switch of the test device to the respective vehicle and brake type (see tables in section 5).
Compare the indicated measured value with the value of the reference table (see section 6).
If the test device always indicates a value 0.00 V check the position of the rotary switch and the connection to the potentiometer connector.
Using the measured voltage you can find the wear status in the tables (see section 6).
If the value is < 2.75 Volt the green LED is illuminated. The wear status of brake pads and disc is OK.
If the value is ≥ 2.75 Volt the red LED is illuminated. The wear status of brake pads and disc must be checked with the wheels removed - refere to respective service manual.
A determination of the wear status (brake pads and disc) using the red or green LED requires the proper function of the potentiometer - see also section 3.
Re-adjust the tappets using the shear adapter until the tappet to caliper distance is the required value for “Minimum Disc + Pads dimension” – see table in section 7.
Compare the indicated measured value with the value on the reference table (see section 6). If the tester always indicates a value 0.00 V the position of the rotary switch
and the connection to the potentiometer should be checked.
If the measured values correspond with the values in the tables within a range of ±0.25V the potentiometer function is correct.
Otherwise the caliper must be replaced.
CHECKING OF WEAR STATUS OF BRAKE PAD AND DISC
