, Salem, MA

November 24, 2012

Auto Scanner: Why are my tires losing air?

Auto Scanner
Larry Rubenstein

---- — Q: I bought a new 2011 Ford Focus in February of 2011. Since I have had the car, at least three times the “low pressure” light came on and I found one or two tires low. The last time, even before the pressure light came on, I had three out of four tires low. This last time I took it back to the dealer and they took the tires off and put it through a water test, checked the stems and told me they didn’t find anything wrong. I have a couple of friends who have a 2010 Ford Focus and they have the same problem. Have you heard of these cars having this kind of a problem?

A: The problem is not just limited to Fords. The problem also happens to a lot of people with aluminum rims. More than likely the air is escaping at the bead seals. The way to check this is to remove the tire and wheel from the car, lay it down on its side, and pour a small amount of water around the bead. If it’s leaking at the bead, the technician should break the tire down and take it off the rim. The technician should clean the bead and coat it with liquid rubber. Once the rubber has set for 15 minutes, remount the tire, check for leaks, and balance. If they find the leak is at the valve stem, a valve stem replacement is also very straightforward. In both cases the tire should be re-balanced and set to the proper pressure. If the dealer refuses to perform the above service, most good tire specialty shops should be able to perform this simple task.

Q: I have a 2004 Mercury Grand Marquis with 40,000 miles. The ride has become rough and I’m wondering if my shocks need to be looked after. Is there a way I can test them to be certain?

A: Your email is of course timely due to road control that is needed for winter driving. Bad shocks can be quite a danger. You can do a bounce test of each corner. More than 11/2 rebounds are unacceptable. There is, however, more testing to be done. The jounce bumpers need to be examined as well as checking for hydraulic leaks. I hope this helps. Bad shock absorbers can also cause tires to set a scalloping pattern on your tire. This leads to tire rotation. Rotating your tires will offset the effect of wearing shocks (scalloping) and less than perfect front end components.

Car Care Tip: As winter approaches, checking your vehicle’s tires is more crucial than ever. A rule of thumb would be to stick a quarter in between the treads of the tire. Insert the quarter head first. If you can see George Washington’s hairline, the tire is ready for replacement. If that’s too difficult for you, then visit your local repair shop. It will only take a minute to check your tires’ tread depth and tire pressure.


Larry Rubenstein is a master technician who owns a North Shore service station. His column appears every Saturday. Write to Larry at The Salem News, c/o Auto Scanner, 32 Dunham Road, Beverly, MA 01915, or send an email to