They will be attached by screws from under the rear deck inside the trunk.
take out the cover, be careful its cardboard, use something flat like a screwdriver.
This question needs clarification. What are you trying to adjust? The level of power brake assist is not adjustable. The only part of the brakes that adjusts (and it should do this automatically) is...
I would like to know how to remove the radio in a 1986 chrsyler 5th avenue
Yes, you will need a screwdriver though, and a smart idea is to put the srews on the back magnet of the speaker
3300 - 3500 lbs (wikipedia.com: look up 1985 Chrysler 5th Avenue)