What happens if on your way back, with required parts on seat of car or in boot, you have an accident and hurt someone? Tricky defence arguing you were unaware of brake issue with required parts sitting in the car and possible bank transaction clearly showing you just purchased the parts; you are then possibly straying into criminal negligence etc .
I would get someone else to drive you there and back for peace of mind, you could have really serious issues if there is an accident; it is likely not worth the risk.