i cant find the button to turn them on
On some VWs of that era you push the wiper stalk forward for the rear wipers.
i would bleed the system pressure seems to be a problem
Does your car have more than one rear windshield wiper? I only ask because twice you referred the rear as having wipers (plural). The rear wiper will run intermittantly if you push the wiper stalk towards the front of the car one click. It will wash the rear glass by pushing and holding the wiper stalk past the first stop.
