How to stop joints from splitting and stretching

Hey everyone.

Can someone please explain a little problem I've come accross while playing with bolts: I have an object that consists of 3 different pieces (upper + middle + lower) connected together with 2 boilt joints (upper piece + bolt #1 + middle piece + bolt #2 + lower piece) so that they can nomally bend. Basicaly, like a finger would do.

I've turned off the collision for all those pieces and made them immovable, so when I press Play nothing falls down and everything seems to work fine. Except for one problem - when I try to bend any piece up or down - both in Play and in Edit modes - there's a clearly visible latency (for lack of a better word) in the movement of pieces that are connected to the one that I'm bending.

So if I try to bend the middle piece (which in turn is connected to the upper one and will move it as well), the middle piece will bend fine, but the upper one (now being forced to follow it's parent object) will drag along slower, showing signs of splitting in the bolt part. It looks as if the upper part is much heavier then the middle part and the bolt can barely handle the tension. However, I didn't change any properties for any of these pieces, they should all be pretty much similar.

Any ideas what can cause this problem? I'll attach a screen that shows one of those joints (that connects here object 1 to object 2) splitting when I manually moved object 2. As you can see, object 1 is not aligned right as a result. Pressing L3 solves the alignment problem, but the joints continue to split when the objects are moving.