Hi, am i right in thinking you are talking about the fixing at the base of the wiper arm on the outside of the car near the windscreen?? if it is, then all i think you need is a nut, its the nut you find under the plastic cover that holds the wiper arm to the tapered spindle, usually tightened with a 13mm socket. Go to any motor factor or garage and tell them what you've said here & they should have the right part, might even fit it for you! the wiper arm will have to be set in its correct 'at rest' position on its tapered drive spindle before the nut is fully tightened.
crabbiepattie, January 2011