For our self employed business I usually take the standard deduction but we refinanced the business vehicle for major repairs. Should I do standard or actual expenses?

You can switch to the actual expense deduction method but you will have to stick with that method going forward for that vehicle. If the repairs you did to the truck prolong it's useful life, you need to set them up as assets and depreciate them over time. You will have to do some calculating to determine what your deductions for the mileage method versus actual costs would be in the future to determine if any additional deduction in the current year is worth switching.