Try tightening the tiny screws at the base of the swing arms. The connection of the shoulders through the two tires wasn't the best idea of the design, but I found that the shoulders on mine stay in place a bit better when I tried that.

What happens is that the swing arm has less place to wiggle or vibrate out of, and the shoulder connectors are more likely to stay connected.

 

Thanks for the tip! I tried it but the screw can't get any tighter.

 

Crap. Just looked at mine, didn't know if I remembered it correctly. You tried to tighten the one, central screw on the blue piece in his back, just above the waist, right? Sorry I didn't describe it better.

Yeah, on mine it did the trick but it might not work on others. The swivel hinge, the tiny pegs on the swing arms meant to plug into the bottom of the chest and the tire connection were probably meant to keep everything secure, but combined with that drastic ratcheted shoulder joint, it doesn't work too well.

 

Yep, that's the one I tried to tighten. It's in there so tight I can't even loosen it! But yeah, I think you're right about the ratcheted shoulders. They're so tight that moving them tends to dislodge what little friction is holding the shoulder/wheels in place. It's almost like the design is a little too ambitious for the size. Perhaps this is another toy that was originally intended for a larger size...

 

got this guy for my sister-she calls him the "scoop um up guy"  

 

pics no do him justice! he is ace.

however, he would be 5 stars if he had bicep articulation and could store his weapon on his back, and if his legs were better, I didnt like the look of him from pics and his alt mode is not what I would normally go for, but his character is awesome and I got him half-price... so with the excellent face sculpt, I'd say if you like Animated - BUY

 

I like this guy,m he's my first and one of the only animated figures I will get. Only other one I plan on getting is Magnus. The legs are annoying though, they aren't in the smooth animated styling...

Thank Primus.

 

I am glad I gave Setinel Prime and the Jet twins a try from discount store. Great fun to play with. Sentinel is a very solid deluxe. It'd be fun if other things fits the toy, like the headmaster, magnus hammer, etc. Overall easily one of my fav bots.

 

I really would like to mod those legs to get him to the height odf Optimus' Voyager version. Not that skilled. I really love this guy except for his feet and legs. I'd love to get a Voyager of him. But while I'm wishing I guess a season 4 would be nice too.