Problems with rear tracking on 2010 bmw 320d

[Spg1981]

I recently went to get the tracking done on my 320d 2010 coupe and I was informed they couldn't do the rear because the bolt was stuck. My dad is a retired mechanic so I'm hoping he can fix it for me, but he isn't sure what part we need to replace?

Is there a way to loosen the bolt? I was told you can't heat the rear bolt due to the seals.

Any help would be great!