Loosen obstructing bolt on left aft tower bulkhead to improve clearance. Tried numerous ways of getting the nut on the left aft bolt, including the use of extensions with the borescope cam. Didn't work. Removed bolt, checked threads and chased the nut threads very slightly. Fabricated a special holder for spinning the nut. Made many more attempts, reaching blind into tower. The nut would go around the bolt, but spinning still very difficult due to tight quarters and threads would not engage. Getting very frustrated; seeking help for subsequent attempts.
