Car Doctor Q&A

Q The front brakes and pads of my 2010Toyota RAV4 were replaced 5,000miles ago and the rears about 10,000miles ago. Lately I’ve noticed that while braking, the brakes pulsate (I’d guess about once per wheel rotation) which is very annoying and that the problem seems to be getting worse. The Toyota dealer verified the uneven braking and noted that the pads are not worn but recommends replacing brakes and rotors on all four wheels at a cost of about $1,100. My local garage says that the problem is with one of the rotors but can’t determine which one, so nothing should be done at this time. So, what do I do: live with the problem or pay an exorbitant amount for an unnecessary brake job?

A The shop should be able to check the brake rotors for out-of-round with a dial indicator. Once the issue confirmed the rotors can be resurfaced to eliminate the vibration. The best method is to use an on-the-car brake lathe. Unlike putting on new rotors or resurfacing the current rotors using a traditional brake lathe the on-the-car lathe can compensate for slightly out of round hubs that could also be causing the vibration.

Q We have two Toyota Priuses, each with 82,000miles one is a 2007and the other a 2010. Both are well maintained driven mostly in the city with an occasional long distance road trip. My question is which Prius has more wear and tear? Is there any handy way to think about these things; simple time passage versus usage or is it more complicated than that?

A The hybrid/traction battery in your Priuses has a warranty of 10years or 150,000miles (whichever comes first). Looking at just battery life expectancy the older car at some point will need a fairly expensive hybrid battery first. The other issue is general wear and tear, like any car age will take its toll. Without knowing anymore about the drivers of each car, the 2007Prius has the most wear.

Q I own a 2018 Mercedes Benz and recently I noticed the highway exit numbers have changed. My question is, would the update to the factory GPS be covered under my warranty?

A Exit numbers have changed to comply with a 2009mandate from the Federal Highway Administration for all states to have exit numbers to match mile markers. This method will allow motorists to know the distance between exits or the miles to a destination. In addition, it should be easier to locate motorists if they break down. The old numbers are required to be posted for two years after the exit number has been updated. Since the navigation system is operating as it was designed it would not be covered under the warranty. I recently evaluated a 2021 Mercedes Benz GLC and the navigation system in this brand-new vehicle had the old exit numbers. At this point all you can do is contact Mercedes Benz customer care and ask about an upgrade to the software.

Q I am considering a new car with pushbutton start and keyless entry. What does AAA do when the battery in a keyless entry car dies, you are on the road and locked out?

A The key-fob contains a hidden key that in most cases slides out of the key fob. The key is then used to open the locked car. In nearly every car there is at least one door lock (it may be hidden under some trim on the door handle. Once inside depending on the car there is a spot to hold the key-fob while pushing the start button. Even a key-fob with a nearly dead battery has enough energy to communicate with the car to get the engine started.