casters

[John Voigt]

When I tuned a Yamaha P22 at a school today I was asked if I could fix the
two front casters as they would fall out when the piano had to be lifted,
such as when going over thresh-holds and such.  I didn't have my tilter with
me nor did I have the time to deal with it today.  That being said, even
though I have seen the problem before, I have not tried to repair it.  I
thought they are held in by a type of spring collar or something.  When the
stem drops out, is there a way (easy or otherwise) to repair it or is
replacement the option?

John Voigt