need help with backing plate/front drum

i went out and did some light wheelin yesterday, and when I got home I noticed there was some play in the left front wheel. Looking closer I can see that where the backing plate and drum come together is real loose. What could have caused this, and what may need to be replaced if anything.

 

The backing plate is bolted to the spindle. If you noticed that the front wheel was loose, it is probably not the backing plate. Sounds like the front hub is loose. Might just need to be repack and have the preload set, or you may be loosing a front wheel bearing.
O.T. Does your '73 still have the Date of Manufacture sticker on the dash? If so, can you give us the DOM and the last 5 numbers of the VIN? TIA

 

nov 72 22872

 

sounds like a wheel barring to me

 

If the backing plate is moving with the drum then one of two things has most likely happened. Either the nuts holding the spindle and backing plate have loosened up (not likely but possible), or the ball joints are worn out. Jack up that side, grab the tire at the 12 and 6 oclock positions and try and wiggle the tire up and down. if the knuckle is moving also along with everything else then the ball joints are bad.
If the backing place is stationary but just the drum and hub is moving then like already mentioned, wheel bearings most likely. Nickmil

 

Yep, its just the drum and hub that is moving. Thanks guys!!