Missing simple plastic bells

[seigezapf]

I have several older Big Haulers.  Every one is missing what I assume are small plastic bells that fit in the plastic wishbone bell holders.  What I see in parts are what look to be much more sophisticated multi-piece metal bell components.  Those are overkill for my inexpensive entry-level locos.  Any suggestions for finding the simpler replacement bells.  Since they seem easily lost, I would probably glue them on if I could find them.  Thanks.