By the time we've reached the legal driving age, those who have gone before us usually instill at least three major lessons we should always put into practice. Number 1: Wear your seatbelt. Number 2: Don't speed. Number 3: Never ever trust your auto mechanic.

I recently caught up with an auto mechanic who agreed to give me some honest answers about the car repair industry in exchange for a little bit of anonymity. We'll call him "Max", and he's got more than 30 years of grease on his hands.

Max said that while the car repair industry is trying to clean itself up, some auto mechanics are still doing things like putting used parts in people's cars and selling them as new.

"I would say years ago, it was more par for the course. I would say it happened about 40 percent of the time," he said. "Today, I would say it probably happens a whole heck of a lot less. You're probably looking at about 10 to 7 percent margin, but it does still happen."

Steering Clear of Shady Auto Mechanics

There are three bits of advice Max gave when looking for a good car repair shop. The first is the proper Automotive Service Excellence (ASE) certification from places like AC Delco, Ford Motor Company or Bendix. "While ASE certification does not indicate that they're really good, it does indicate that the technicians go on their own time, or the business has given them the incentive to study, to take the course and go and show their skills are worthy of certification." (Ed. Note: ASE is a non-profit, independent organization founded in 1972. To learn more click here.)

Max also wants to see that a car repair shop has all the right equipment in place (like a proper tire mounting machine with rubber mounts that don't scratch your wheels or an alignment rack with laser measurements) to do the job well. "I want to make sure they have the proper diagnostic equipment. A shop that has invested in the proper equipment to service today's automobiles is usually a shop that you can trust, because they are not going to buy that expensive equipment and then have people who are not qualified to use it."

Max also advises that a good car repair shop should also be somewhat tidy. Max says, "I'm looking for a clean shop. I don't want to see Jake the Junkyard Dog chained in the office. I don't want to see a lot of dirt around the place. It shouldn't look like it's going to be condemned by the health department." Sorry Cooter.

Besides a car repair shop's cleanliness, Max says the price for car repairs should be clearly posted, and they should always call you with a car repair estimate before they do any work. You should also be able to get some positive feedback about the car repair shop from people who've been there. If an auto mechanic has been recommended to you, make sure it's more than just, "Well I go there because my father's cousin's grandfather used to work there and they're really nice and they make a good cup of coffee," he said. "It's got to be better than that, they've got to have a track record of good quality repair."

Little Old Ladies, Beware

With three decades of experience, Max has come across some car repair shop scenarios that would make anyone want to sell his vehicle and start biking to work. He told me about a situation in which a co-worker used a scare tactic in order to trick an elderly woman into getting repairs done on her car. Max relayed the waiting room conversation between Mrs. M and the auto mechanic.

Mechanic: Mrs. M., what street do you live on?

Elderly Woman: I live on Elm Street.

Mechanic: I live on that street too. What time do you come home in the evening

Elderly Woman: Oh, about 5 o'clock.

Mechanic: Good. Then I'll know what time to tell my kids to get off the street because I shudder to think of you driving down the street in this car with my children playing in the street because you're driving a death trap and it could kill them.

"Well needless to say the poor little old lady, just shy of a heart attack, started crying and saying, 'Just do it, fix it, do whatever you have to do!' And this is the type of tactic this guy used." Although Max said these situations don't happen as often as they use to, but there are instances where mechanics use such unscrupulous tactics.

Window Shopping

As an auto mechanic for more than 30 years, Max has come across a few annoyances that really get his oil pressure rising. I asked him what types of things customers do that really annoy him and with no hesitation he says, "People who are shopping auto repair prices."

Max gave me a hypothetical situation of people who call up wanting to know the cost for a tune-up, but don't really know what's wrong with their car. The symptoms they give usually require a different procedure. Max usually hasn't gotten a positive response when he mentions the dreaded diagnostics test that so many people hate paying for. He suggests that it's time and money well spent though. "You're paying for a skilled technician to take an hour's worth of labor to diagnose your vehicle with the proper computer scan tools to determine where your drivability problem is."

Let's Make a Deal

The other types of customers that Max doesn't quite enjoy are the ones who come in and say, 'Can you make me a deal?'" Although, Max says that he does try to look out for people who actually do need help and aren't just looking for a discount.

If a pregnant woman with two kids who worked at McDonalds came to him crying about her car repair problem and didn't have a lot of money to fix it, he told me, "I'm going to the ends of the Earth, to the gates of hell for that woman to get that car running as reasonably as I possibly can and still maintain a profit for my business." Even when helping others, Max says that his line of work is not a charity organization. "I don't wear a white collar and consequently, I can't stay in business if I give away everything I do."

Trust Wins Points

The customers who Max appreciates are the ones who trust him to do his job. He had a customer years ago who would drop off his car and tell Max to take care of the car repair. He never cared what it cost and never wanted a telephone call. He simply trusted Max as his auto mechanic to get it running again and to do his job right. "And I never breached that trust," Max said.

Consequently, Max would adjust his booked schedule, sometimes two weeks' full, in order to get the guy in and out in the same day. "I took care of him. Did I give him a discount? No ... did I do everything I could to get him back on the road as quickly as possible? You're damn right I did. And I did it over, say the guy who came in an hour before and said, 'Can you make me a deal?'"