Quote:
Originally Posted by spock505
Yup, captive washer although I may have just have invented that terminology 
Basically the washer is held in place by a small recess under the bolt head.
I can have a look at mine to see if there's anything that looks obvious. |
A captive nut is used on many older British and some older US cars ( fender mounting ) It uses a square nut in a thin sheet metal cage. The entire mess clips into a square hole opposite to what you want to attach. They usually don't survive removal if there is much rust on the threads.
A captive washer is a proper term for a washer that is free spinning but does not fall off the threads.