You can check collimation quite easily using an SLR and medium telephoto lens.
I have instructions on my site (http://elekm.net/zeiss-ikon/repair/collimate/
A lens can focus past infinity.
The more I thought about this, the more I would be inclined to check the collimation of the lens.
There is also the possibility that the linkage between the actuating arm under the lens and the rangefinder assembly is damaged.
One other thing: When turning the focusing ring, ensure that the lens itself (look at the name on the lens face ring) also turns in tandem.
Finally, check to make sure that the last four or five digits of the serial numbers on the front and rear lens elements match.
I've not encountered a Tessar that misfocused, because it's not that complex of a lens -- just four elements.