So I created a motion study and all was going well until I inserted a spring into the study. There is a pusher block which pushes a gripping block forward, the problem initially was that a spring is needed to return the gripper block to its start position. When I insert the spring, the gripper block doesn't reach its full forward travel and there is a resultant "overlap" between the contact face of the pusher block and that of the gripper block.
I have tried a number of times to resolve the issue but with no luck. The strange thing was that in a similar motion study of an assembly with the same function but different geometry, there was no problem with the spring.
For further clarity have a look at the clip below.
I am a bit fresh, but I'll give it a try.
What material do you use in the body contact definition (looks like rubber )
If steel, use "impact" in Elastic properties and make sure you have not changed the settings.
Last try for my two cents, try increasing the accuracy of thre analysis. It looks to solve (to) quickly....