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» Y119119 – (EN - REV. 001) | JULY 2020
2. Operation of the tester
Before operation of the tester a 9 volt battery must be inserted in the battery compartment on the rear of the device (battery not supplied). If the yellow LED on the front of the device
illuminates, the battery must be replaced. Otherwise the accuracy of the indicated values cannot be guaranteed. Switch off the device after use by turning the rotating switch to “Off“.
3. Check of the potentiometer function
The procedure for checking the potentiometer can be carried out with the caliper installed on the vehicle or with the caliper removed.
In either case, it is necessary to be able to measure the distance between the tappets and the opposite caliper face – see dimension ‘X’ in section 7.
In the case of disc brakes fitted with two tappets, it is important that the distance between the respective tappets and the opposite face is within ±0.25mm of each other. A table in
section 7 provides the dimensions for each disc brake type.
Setting the dimension is easily achieved with the caliper removed but, if the caliper is installed on the vehicle, it will be necessary to measure ‘over’ the disc using a vernier caliper or
suitable fabricated device.
3.1. Read the Safety Advice Section of this manual.
3.2. Only if caliper is installed on vehicle
Remove wheel.
Disconnect the vehicle cable plugged into the potentiometer on the caliper.
Wind back the tappets using the shear adapter and remove brake pads.
3.3. If caliper installed on vehicle or removed
Adjust tappets using the shear adapter until the tappet to caliper distance is the required value for “Maximum Disc + Pads dimension” – see table in section 7.
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 of the tester 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).
For detailed instructions on the necessary service steps, observe the respective service manual for air disc brakes - refer to section “Brake Identification and Service
Manuals“.
The threaded tubes must not extend more than the “Absolute Minimum dimension“ see table in section 7, otherwise synchronization will be lost and the caliper must
be replaced.
CHECKING OF THE POTENTIOMETER FUNCTION
