motormouth bob weber
Q: Three days ago I backed my 2007 Subaru Tribeca down the driveway and applied the brakes. The brake pedal did not depress. After pumping the brakes for about two minutes or more they finally started to work. My wife insisted that she told me this happened every winter when the temperature was below 25 degrees. I guess I never listened to her. I took the car to the local dealer and he stated this was a typical problem with the 2007 Tribeca and I would waste my money trying to fix the problem. I then checked online and found that this was a common problem that many people had with a freezing check valve going to the booster. This is a serious and dangerous problem and there should be some sort of fix.
A: Although uncommon, ice forming in the brake booster's vacuum supply hose happens. Usually, it is due to a low point in the hose where water accumulates. Rerouting the hose fixes it. As for Subaru, the problem is different. There is a vacuum check valve in the hose designed to maintain vacuum in the booster for brake application if the engine stalls. First, the source of moisture should be investigated and eliminated and then the check valve and hose assembly may need to be replaced.
Q: You mentioned that disconnecting the battery may cause loss of component settings, which would require reprogramming the control module. What happens when replacing the battery with a new one?
L.J., La Grange, Ill.
A: During battery replacement, professionals (and wise do-it-yourselfers) use a memory saver device. Although there are inexpensive tools which you power with a 9-volt battery and plug into the cigarette lighter socket, they won't work unless the socket is hot even when the key is turned off. Better memory savers plug into the onboard diagnostic connector found under the dash near the steering column.
Q: My wife got a nail in her run-flat tire, and they cannot repair those if the nail is in the outer row of tread. Fortunately we needed only to replace that tire because it had just 7,000 miles. We also realized that calling AAA is not going to help her because they cannot do anything to fix it. And if she gets a flat in the middle of nowhere, she really (has a problem) because even if you can make it to a garage in the tire's 50-mile range, they will likely not have the tire in stock. Here, even NTB had to order it from their local warehouse.
A: Yes, run-flat tires are not the panacea that had been hoped for. The tires are not cheap, either. Many motorists switch to standard tires when replacement is due. And, nowadays, carmakers are simply providing a kit with tire sealant and a battery-powered compressor in the trunk. It might actually get you home and you might be able to get the tire fixed.
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 firstname.lastname@example.org.