Question: I have a 1984 Oldsmobile Cutlass. I tried to replace the screw-on-type paper fuel filter, but it was so tight that I stripped the flats on the filter's fittings. I tried two types of penetrating oil. Now, it seems I have to cut the pipe and replace it with a new fuel line. Any suggestions?--J.P.
Answer: Sometimes even the most routine car maintenance becomes a nightmare of ever-increasing trouble. Stripping a bolt head or screw slot is one good example of how simple things go wrong and can turn a 10-minute job into a wasted Saturday afternoon.
It's not uncommon to strip fuel filter fittings. I've even seen an experienced mechanic do it, much to his chagrin. Usually, a stripped bolt or screw results from not using the correct tool or from rushing the job.
A five-sided line wrench or a six-sided socket wrench is helpful for small fittings. Don't ever use an adjustable wrench on a small fitting.
You should also be careful of metric-size nuts and bolts. An English-size wrench will sometimes fit a metric head, but only poorly.
As a result, when you get a really tight fitting, it will strip the head. In addition, the right time to use the penetrating oil is before you strip the bolt, not after.
Because your fuel filter is completely rounded, no wrench is going to work anymore. I would try a set of very large channel-lock pliers, with 10-inch or 12-inch handles. You may get enough leverage to get the filter free. A set of large vice-grip pliers may also work.
Do not attempt to heat the fitting, because there is fuel in the line. I'd also be careful about sawing into the metal line, because that can be very dangerous around gasoline. In any event, you should plan to replace the metal fuel line that runs from the fuel filter to the carburetor.
Q: I have a 1985 Buick Skylark with front-wheel drive. At 30 to 35 mph, it has a dull humming noise that seems to be coming from the right front wheel. I bought new tires and had them balanced and aligned. Any help?--W.G.
A: A humming noise from a wheel is frequently a bad wheel bearing. Try to determine whether the noise changes with speed. If it does, you can be more confident that it is a wheel bearing.
Another part that wears out on your car is the universal joint. Those joints usually clunk or clank when the car is shifted into gear, but they sometimes make a whirring sound.
Incidentally, wheel bearings can make a horrible noise, even though they don't appear to be worn out because of excessive wheel play. A good mechanic should be able to pinpoint your problem without too much trouble.
Q: My mechanic inflated the tires on my 1984 Toyota Tercel to 30 pounds per square inch. My owner's manual says the pressure should be 26 psi. Will this extra pressure harm my tires? The car rides and handles better now.--J.R.H.
A: Excessive pressure will cause the tires to wear out in the center, an effect called crowning. But it takes a lot of excessive pressure to cause crowning, and if you watch for it carefully you can stop it early on.
Toyota recommends 26 psi as the best compromise between comfort, handling, fuel economy, tire life and safety. Increasing the pressure may moderately reduce your car's stopping distance.
Ralph Vartabedian cannot answer mail personally but will respond in this column to automotive questions of general interest. Do not telephone. Write to Your Wheels, You section, The Times, Times Mirror Square, Los Angeles 90053.