Q: I took my 2014 Kia Soul in for its 7,500-mile service. I have a little over 31,000 miles on it; we are seniors and don't do a lot of driving. In looking over the inspection sheet at home, I noticed that for "brakes remaining" it showed 5 mm on the front and 7 mm on the rear. Is the difference something to be concerned about?

A: The difference in thickness is normal. Because they do up to 80% of the work, front brakes usually wear faster than rears. But don't be surprised if your service adviser recommends replacing the front brakes the next time you bring in the car. As a rule of thumb, I suggest replacing the pads when there is 4-5 mm remaining.

Keep it quiet

Q: I have a comment on your response to the recent jake brake question. You said the only option for reducing the noise caused by the brakes is to ban their use. My experience is that the majority of heavy-duty trucks built in the United States over the past few years are not noisy when using the brakes. The noisy trucks are those where the driver has removed the muffler. A better response would be that the best option to reduce the noise caused by compression brakes would be to require drivers to have a standard OEM muffler and exhaust system on their truck.

A: I hear you. But I did not suggest banning jake brakes. I suggested restricting their use in residential areas. In fact, I would appreciate if truck drivers would avoid any engine braking in town. Speeds are low and service brakes should suffice.

Spare solution

Q: I noted your response to the reader who was surprised to learn that there was no spare tire in their 2013 Cadillac SRX. I have a 2010 and had the same issue. I purchased a spare tire complete with the jack for peace of mind if I ever had a blowout. When I sell or trade in my 2010, I'll put the pump and sealer back in the car and then sell the spare tire and jack to someone who has the same needs as I did.

A: That's a good solution and one that many other motorists have chosen.

Put the lead in

Q: My father has a 1923 Packard. He has to change his spark plugs often because of (I am not a big car guy) gunk buildup. He didn't have this problem when he used leaded gas. It's hard to find that nowadays. Is there some kind of additive to make the gas "leaded"? Or can you suggest another solution?

A: Spark plug fouling can be due to oil getting past the intake valves. The valve seats regress after prolonged unleaded gas use. In bygone days, lead would deposit on the valve seats, effectively giving them a cushion. Lead substitutes are sold in auto parts stores, but having never used them, I can't vouch for how good they are. They are worth a try, but if the seats are damaged, no magic in a bottle will repair them.

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician. His writing has appeared in automotive trade publications, Consumer Guide and Consumers Digest. Send automotive questions along with name and town to motormouth.tribune@gmail.com.