What's The Difference?

[Dusteriffic]

Hey guys, newbie A-body guy here....

What's the difference between upper control arms from a 73-76 disk brake A-body and a non-disk brake A-body?

I've never seen both UCA's side by side, but I'm curious as to why everyone (on eBay) says you need the correct UCA when going from drum to disk?

I've heard the ball joints are bigger on a disk car, but it was my understanding that all A-bodies went to the bigger ball joint in 1973 regardless of braking system. Was I misinformed? Help!

Also, are the spindles different as well? Thanks.

 

[rumblefish360]

Theres a link here to a mag article on the problems and differences on the upper A arms. Give a look. I think it was MoPar action or Muscle, maybe both that did it.

 

[dgc333]

As far as I know in 73 went to the bigger ball joint (same joint used in B, C and E body cars) in all A-bodies regardless of whether they had disks or not.

When swapping to the A-body 73-76 disk brake setup in a 72 or earlier A-body you need the 73-76 upper control arms because the small ball joint doesn't fit the disk brake spindle and the big ball joint will not fit the 72 an earlier control arm.

With your 76 Duster you should only need the spindle and not the control arm (pluss the caliper, caliper mount and rotors of course).

 

[Dusteriffic]

Thanks, Dave. You and I seem to agree, but I would feel even more comfortable if others would agree with us. What do you say, guys?