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Automania/Repair & Maintenance
AUTO QUESTIONS AND ANSWERS FOR WEEK 20 YEAR 2000
by Bob Hagin
Q. I purchased a new 1999 GMC Sierra half-ton pickup and I'm unhappy with the stiff steering. The vehicle has been taken to the dealer's shop twice but the manager says that the steering meets the factory specifications. I have a friend who has a 1999 three-quarter ton GMC truck with conventional recirculating-ball steering and it steers nice. I have driven two other half-ton GMC trucks and both of them steer stiff like mine. Have you had other complaints about the 1999 half-ton GMC? Do you have any suggestions as to how to improve the quality of the steering? I have not contacted the factory as I feel I would be wasting my time.
A. It's not a waste of time to contact the GMC factory to register your complaint even if it's just to get it on file as long as you don't get your hopes up about the results. Since your problem is simply a poor design rather than a safety hazard, the National Highway Traffic Safety Administration probably would not be of any help either. If you tried two other trucks like your own and they have the same stiff steering, it may indeed be true that they all do it. I don't put much faith in your service rep's comment that your truck "...meets factory specs.." unless there are qualitative specifications that tell how much torque is to be applied to the steering wheel, at what speed the test should be made, etc. It's possible that a readjustment and change to the front suspension alignment specifications would lighten up the steering, as might a change to different and narrower tires. Unless the steering got stiffer after you bought the truck, I'm surprised that you bought it after your pre-purchase test drive.
Q. I have an '86 Subaru and going up hills or mountains it loses power and will go down to 45 and even 35 MPH with my foot on the floorboard. The mechanics say the catalytic converter is clear. I have replaced the fuel pump and the filter from the gas tank and the carburetor has been set leaner. I had to replace the alternator because it quit on me but I can't see how that is the cause. I also replaced the cylinder heads with reconditioned ones and was told the compression was within good limits. As an old mechanic, I'm at a loss with these newer cars.
A. The basics of the auto remain the same. Look at the action of the secondary venturi side of your carburetor with the air filter off. It's possible you're simply running on just the primary side under an uphill load but aren't noticing it on level driving. If the carb is OK, check the ignition timing to make sure the mechanical and vacuum advance mechanisms are working. Check the cylinder head compression pressure values to make sure your "new" heads develop sufficient pressure (100 to 140 PSI). Make sure the camshaft doesn't have any "flat" lobes that would sap power. Remove the muffler and make an uphill run to see if it's plugged, then do the same with the catalytic converter. All these things can be checked on a chassis dynomometer if you don't want to wake up the neighbors. Troubleshooting is just a process of elimination.
Q. What is the best way to repair a flat tire that's been caused by a nail? One gas station said they don't put in plugs but instead put a patch on the inside of the tire, thus requiring a spin-balance of the tire and rim costing $18. I could have bought a new tire for a few dollars more. Using a plug sometimes makes a noise.
A. If you had bought a new tire, you'd have had to get it balanced too. I like to have a plug put in with a chemical bonding agent because it seals up the hole completely. If it isn't sealed, moisture and other debris can get into the carcass which can lead to ply separation.
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