Automania/Repair & Maintenance

AUTO QUESTIONS AND ANSWERS FOR WEEK 14

by Bob Hagin

Q. I want to try doing a home restoration on my 1968 Chevrolet Nova. It's not worth an expensive professional job but I'd enjoy trying it myself. Are step-by-step how-to books available on the subject? B.H. Tampa, FL

A. There aren't many home shop how-to books on body work available but Classic Motorbooks (1-800-826-6600) has a couple that center around restorations. Call them for a catalog. The Eastwood Company (1-800-345-1178) has a video on patchwork and Motor Cam (1-800-240-1777) sells three videos on the subjects of rust repair, body repair and paint preparation put out by Triangle Productions. I have these myself and used them in my days as a high school auto shop teacher.

Q. I'm having trouble getting my wife's 1993 Ford Thunderbird repaired right. We had to have a brake job done at 41,000 miles and then another only 3000 miles later. The problem was that the pedal pulsated when the brakes were applied at freeway speeds. The back brakes were OK but the fronts needed new pads and the rotors machined because they were warped. After another 3000 miles, the shimmy returned and the job had to be done again. The service manager said that a caliper pin was stripped and had to be replaced as well. Now at 51,000 miles the job must be repeated but the rotors now have to be replaced rather than machined. What causes a caliper pin to strip and what does it do? R.C. Pleasant Hill, CA

A. The calipers on the front brakes of your Ford are like the brakes on a bicycle and the rotors are like its wheels. The calipers cause the pads to pinch the rotating rotors to slow the wheels down. The rear brakes on your car use drums and shoes and work on a different principle. Front brakes do the majority of the work in slowing a car (as much as 70 percent in a high-speed stop) and traditionally they wear somewhat faster. If the fronts get overworked, the pads wear quicker and the rotors get overheated and warp. When this happens, the driver feels it as a pulsating brake pedal. Warped rotors can be machined down just so many times and then they have to replaced and that's what has happened to your car. Front brake wear has been a major problem with T-Birds of that era and I suspect that the front-to-rear equalizing system was designed wrong. Ask your shop to check its service bulletins for a permanent cure. The calipers are of a "sliding" design and slide on the caliper pins. Pins get stripped when someone puts them in wrong.

Q. I have a 1990 Dodge Omni with a manual transmission. Every time my gas gauge reads from a quarter tank to empty, the car stalls when I come to a sudden stop. It then takes several minutes to start again. It becomes a real problem when I'm in heavy traffic but it never happens when the tank is over a quarter full. The problem occurs in winter as well as summer. I have had the fuel filter replaced and I use premium gas but I can't seem to find the problem. I asked a couple of mechanics and they look at me like I have two heads. F.L. Lansdale, PA

A. The easiest quick-fix is to never run on a low tank but that doesn't solve the problem. If a car shut down when it came to a sudden stop only when the fuel level was low, the first thing I'd look for is a fault in the pickup system inside the fuel tank. I've seen internal pickup tubes develop cracks which make the system pick up only fumes when the remaining fuel sloshes to the front of the tank. It may be that you have slightly too much water in the tank (it comes in from the atmosphere as the fuel level drops) and the system picks it up under those unique conditions. Put a couple of cans of a gas-drying agents in a half-tank of gas to absorb fuel-tank water, drive it 50 miles or so and repeat the stall conditions. If that doesn't cure it, have a mechanic look for a fault in the fuel tank delivery system.