Bad repairs can happen but they're not always results of bad will, just honest mistakes. But when you pick your car up, do not leave the mechanics shop until you do the following:

Check the work order of receipts very carefully unless they charge a flat fee for the repair. Make a thorough visual inspection of the work that has been done and speak to the mechanic and ask questions about anything you don't understand before you pay.

Check the warranty of the work if it covers both parts and labor. The warranty should be at least 90 days or even better 6 months.

Give the car a good test drive and return to the shop immediately if the problems still exist. Offer to take a ride in the car with the mechanic so he can see what the problem is.

Ask to speak to the shop manager if the mechanic will not look into the problem immediately. Explain to the manager, as specifically as possible, what the problem is, calmly. Ask for the problem to be fixed immediately. The manager should be aware of the shop's reputation and willing to help.Inform the manager that you're canceling the repair payment if he/she refused to admit the car immediately.

Consider going to another shop for second opinion but be aware that if you choose to go to another shop, the original shop may not honor the repair warranty while the second shop may not want to deal with the problems if someone else had already worked on the car.

Contact the Better Business Bureau or other state agency that regulates auto repair if the problem still not resolved.