Get the right tools and don't bodge. Without the piston winder you stand to cause damage to the piston or the dust boot.
Keep the pedal locked down whilst you retract the pistons and expell the fluid via the bleed nipple. Forcing dirty fluid back through the ABS unit is unwise. Then bleed the brakes and top up the fluid.
![2017 Volkswagen Golf 1.0 TSI 110 SE [Nav] 5dr](http://images.honestjohn.co.uk/imagecache/url/crop/90x60/https/cdn.uk.prod.group-mobility-trader.com/images/cas/9272ee3e7ebeee4382be543c66da9504/85e6984960d610f38fd0ab534cbb3b78.jpg)
