How do I calibrate a new lens?

I've been using my newly acquired M3 for about 6 months now; after the CLA it has worked beautifully. I decided to pick up a portrait lens in the form of a 90mm collapsible Elmar...long story short; I developed my first roll and all my 50mm shot are crisp and all of my 90mm shots are out of focus. That being the case, is calibrating the lens something I could do; or am I asking for trouble? Also, if I sent it out for service, would it cost me more than the lens is worth and would I need to part with my camera?

Thanks all for any advice; I usually feel comfortable tinkering with something...but I'm hesitant to try it on my Lecia!

The first time I ever used a Leica, I borrowed my Uncle's lllf with a collapsible 50mm, f3.5 Elmar. I shot 36 exp. and ALL came out fuzzy. Long after returning the camera (I found my uncle did not know any more about the camera than I did), I found that after you mounted the lens on the camera, you had to pull the lens out as far as it would come and then lock it into position. Many years later when I mounted a 90mm collapsible Elmar on my M2, I found that pulling the lens out all the way was vital to getting a sharp picture. The same thing is true of a collapsible 50mm f2 Summicron that I use today. I would be very surprised in anything is really wrong with your 90mm lens...Regards