Vauxhall Zafira 04 front wipers crashing?

Paul, it is likely the wiper arms have 'spun' on the wiper spindles. You will need to release the locking nut at the base of the wiper arm - usually under a flip up plastic cover- and remove the arm from the splined spindle. Make sure the motor is at 'park position and refit the arms in their proper place, secure the locking nuts and test.

Mark W
February 2009