Buying a second (used) car for work, what deductions can I take?

I am buying a second car, used from a private party.  I will be using it about 90% of the time for work, having to drive to and from work sites.  I know about the standard mileage deduction, but I just had to get some work done so the car would be safe to drive (i.e. brake job, motor mounts, oil change).  Can I deduct the cost of those repairs, insurance payment, gas receipts at 90%?  What about the purchase price of the car, is that deductible?