Rear Brake Drum Bolts

[marvmay@ix.netcom.com]

Does anyone know the purpose of the 3 small (1/4 in.) bolts that go through 
each rear brake drum?  
I broke one on each side trying to take them out to get the drums off and had 
to drill them out.  
Are they really needed or are they only there to hold the drum in place while 
you put the wheel 
on?

Marvin May
VIN 1343