I was wondering if anybody knows how to install a 1980's model Raleigh crank arm. It fell off of my friends bike while he was riding. The square bolt is still attached to the bottom bracket. Any help is appreciated.
if it fell off, it probably has been loose for a long time and is damaged beyond useable.
That said; unscrew the round cap (a coin works as a screw driver); underneath you will find a loose nut or bolt. Put the crank back on the bottom bracket (BB) axle, re-install the nut or bolt (usually takes a 14mm socket), tighten until the crank is fully seated (no wobble).
If there is any wobble, a new crank is required.
Awsome thanks that helps a lot. If a new crank is needed, what style/size crank would i look for.