I have the mates set so that the two upper cylinders move upwards and apart as well as the lower cylinders, independently at the moment. I am having problems keeping my mates happy. I have a limit angle mate set for my stops from the stop block face and the face parallel when closed. I also have gear mates set between all the cylinders.I have much more work to do to this but I am having severe problems with the mates going to crap whenever I start moving the parts around. Everything seems to be set right and I cannot figure out what I am doing wrong. I move the arms or the cylinders and then I start erroring out on mates and parts go everywhere! I rebuild after having problems and it gets even worse... I am still a newbie to SolidWorks but I thought I could figure this one out by now and I am becoming a little frustrated!!!

I would really like to set my mates as to where an air cylinder would be connected to the top and bottom brackets to spead and close the cylinders, but I am having problems with what I have already. I am not concerned at the moment with adding screw mates to the clevises, and I have a center distance set between the clevis pins.

One mate that I am not comfortable with is the limit angular mate between the stop blocks and brackets. What my intentions are include having all the cylinders touch and have the stop blocks set at that location. I think that is what I have already but I am not positive it is accurate. I am also wanting to locate pins above and below (respectively)  the top and bottom arms. I would like to set a mate between the pins and the arm to have the pins work as a positive stop. Is this possible?

I believe the file attached is the file where everything is working at the moment. Drag parts around a little and they will quit moving. Rebuild the assembly and parts start to scatter! (Maybe it is just my touch...)

Please feel free to let me know what I am doing wrong (and please don't be afraid to let me have it!).

Thanks!!!!!

P.S. I know many of my scetches are under defined. They are mostly exixting 2D dwgs that I have extruded....