ZWHEEL T4 Serie Manual Del Usuario página 50

Brakes
If the brake is too tight or has play, use an M5 hex wrench to adjust
accordingly and push the pistons back in as far as possible, being careful
not to bend them. Do not push the pistons with a sharp tool, as this may
damage them and cause further damage.
Then turn the screw from right to left, keeping the brake lever pressed.
Squeeze the brake lever several times to check that the brake operation
stiffens. Remove the pad spacers and check that there is no interference
between the disc and the calliper. Once this work is done, no squeaking
should be heard.
Stem Vibration
In case you feel vibration in the
handlebar/stem, please use the hex key to
adjust the folding/unfolding mechanism of
the scooter.
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