According to Hasbro these two interact some how:
March 2010 Q&A with Hasbro's Transformers Team!

I fiddled with mine for about 15 minutes earlier to no avail, anybody got any ideas?

 

I'm all over this!

 

They may not be referring to those two figures interacting with each other, rather they're probably suggesting that there are interactive points on both figures in general that haven't been suggested yet.

 

Brakedown's waist piece that swivels(the black piece) has a cross-shaped hole cut out of it. But as you flop it over from position to position, you can see that it only uses the same length-wise cut. It never uses the perpendicular cut. Maybe he can click into another transformer that has a cross-shaped peg?

EDIT: Nevermind. Literally, the second I posted this, I saw that when in robot mode, the blue hip piece has two little pegs that go into the perpendicular cut that I thought wasn't being used.

Back to the drawing board...

 

Hmm. It's possible that Recon Ironhide's guns clip onto Brawn's pipes that he has on his back wings and shoulders.

 

Maybe they meant "interactivity" along the lines of Brawn ripping off Brakedown's arm, and beating him with it >_>

 

I saw that on the Q and A's, and fiddled for a bit with the two last night. Couldn't come up with anything.  

Maybe they meant someone else? Or this:

 

I don't have a Recon Ironhide to try this with, does it look like it works well?

Still leaves Brakedown up in the air. I figured he'd use Brawn's pistols in some fashion like how Lockdown uses Ratchet's EMP.

 

I took Brakedown apart to being painting it the other day and didn't notice any additional holes or pegs (clips etc).

Brawn was at some point supposed to interact more with Scattorshot was he not?

 

Very. First thing I figured with 'im. Skystalker's hatchets also use the same clips.




Sadly, I don't own Brakedown, sooo~

 

Hmm the clips make perfect sense. I'll fiddle with Skystalker's weapons to see if Brakedown has any similar clips.

 

Skystalker's clips are a bit different from Ironhide's though - there are extra, smaller pegs so that Ss can hold his weapons. Any similar holes on Breakdown anywhere? From the TFW Resources, I don't see any rods for the clips to attach to in the same manner they do on IH and Brawn.

 

i'd also like to mention that you can spin (not freely) Brakedown's spoiler.

 

hrmmm interesting.

 

Just noticed this, but the bottoms of Brakedown's hands are compatible with the clips on Skystalker's (and presumably R-Ironhide's) weapons:

 

Aaaaand that'll do it.

 

I guess these clips count as different universal system now like the 3mm one we've had.

 

I think Hasbro addressed it in a Q&A a few months back, saying 1) they don't want to make it seem to kids like there's a "proper" way to play with Transformer toys and 2) to give us collectors some little "easter egg" for us to find. Discovery is half the fun!