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Automania/Repair & Maintenance
AUTO QUESTIONS AND ANSWERS FOR WEEK 47
by Bob Hagin
Q. I have a 1997 Chrysler Concorde with 28,000 miles. While traveling on the freeway at 70 MPH, the traffic would start to slow down and I'd depress the brake pedal. When I did this, the steering wheel would start to shimmy. Under 60 MPH there was no shimmy when I stepped on the brake pedal. It only happened over 60 MPH. I went to my selling dealer and was told that the problem was wear and that my warranty was void. I then went to an independent repair shop and he resurfaced the brake rotors and said that the brake pads were like new. He also said that it would happen again. Is this normal? I've had five cars with disc brakes and this has never happened before. One had 30,000 and another one had around 80,000 miles before I had to have brake work done.
A.The brakes on an automobile are really heat transfer machines. They convert the energy of forward motion into friction (the pads or shoes rub against rotors or drums) and then into heat which is dissipated into the atmosphere. If the rotors on a vehicle become overheated (I've seen them glow red-hot at night), they can easily warp when they cool off rapidly as when the driver gets on and off the pedal at high speed. If the pads material is the right consistency, they will wear at a predetermined rate and not overheat the rotors. In some cases, the rotors get so hot they develop "hard" spots in which case they have to be ground down rather than simply skimmed. It sounds like the pads on your Chrysler are too hard and perhaps should have been replaced with pads a little softer or maybe the rotors weren't "true" when they came out of the factory.
Q. I have a 1999 Hyundai station wagon, series ELSASW, which I bought a few months ago. The mileage is now about 9000 miles. It's a nice automobile except for one problem. Whenever I hit the accelerator hard to pass or when approaching a hill, it pulls noticeably to the right. The dealer tells me that they all do this due to some front end imbalance and that there is nothing he can do about it. It's pretty hard for me to accept this explanation and I'd sure appreciate it if you could help me out on this one.
A. What you're experiencing is torque-steer, a gyroscopic phenomena that happens in front-drive cars. It's particularly prominent in front-drive vehicles that have lots of horsepower (not a problem in the case of your Hyundai) or when the accelerator is hit hard in icy or wet conditions. It's possible that your wagon has a malfunction in the front end that causes the pull but it will take a close examination of all the alignment specifications to pinpoint the problem if one exists. A quick way to check to see if "... they all do it..," is to drive another one like yours under the same conditions. If it's a problem on all '99 Hyundai wagons and it's unsafe, the National Highway Traffic Safely Administration should learn about it. If it's limited to your vehicle, the factory should be informed and they should fix it.
Q. I have been using my sister's 1985 Chevrolet Cavalier, four- cylinder, automatic transmission and I have a problem in that the cooling fan does not come on. The fan switch is OK and so is the temperature sensor. The relay is also OK. Right now I have bypassed the switches and have a jumper wire to the relay and the fan runs all the time when the motor is turned on. Could you please tell me how to get this fan to turn on automatically as it was originally intended to do? I cannot play the radio without the fan coming on.
A. Put things back the way they were, get a wiring diagram (try your local lending library for a photocopy), then use an electrical continuity tester to see where the current interruption happens.
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