Automania/Repair & Maintenance

AUTO QUESTIONS AND ANSWERS FOR WEEK 34

by Bob Hagin

Q. I have a 1990 Volvo 740 and I had the front end aligned. I was told that the camber is out of alignment. The mechanic who did the job said that there was no way to adjust this. If this is true, it will cause my tires to wear abnormally. What can I do to prevent this from occurring? Rancho Cordova, CA

A. Your Volvo is equipped with a MacPherson strut front suspension and getting the front wheels into alignment can sometimes be a problem. The strut consists of a long tube-like unit with a pointed spindle on the bottom that carries the wheel, wheel bearings, tire, brake, etc. There's a ball joint on the bottom attached to a transverse link and a stabilizer bar. The top of the strut is mounted to a "cup" that's built into the body. Traditionally, these units have a wide latitude of measurement that allows for a plus or minus of many degrees and is still within the factory specifications so in many cases, the manufacturer doesn't build in a method of making camber or caster adjustments. The aftermarket auto parts industry saw an opportunity here and several companies produce caster adjustment kits (usually a simple "eccentric" bolt that replaces the standard unit) that allows for a camber adjustment of several degrees. The 1998 Source Guide issue of Motor, an auto repair trade magazine, lists over 30 companies that produce alignment shims, cam bolts and wedges for aligning front and rear suspensions. It may take some detective work on your part, but I'm pretty sure that someone makes something to do the job. I found a race car outfit in Colorado (Ingalls Performance Suspension Components) that makes them for one model Volvo, but the tech there said he's not sure they fit a '90 740. Try your local aftermarket parts stores. They'll have the info you need in their jobber catalogs.

Q. Last year I bought a '94 GMC pickup from a very reputable dealer. Later I noticed a whine or howl in the differential at 45 to 50 MPH. Everything was normal at other speeds. I had a one-year warranty on the power train so I had it checked by the dealer. The shop there said it has some bad gears in the rear end. They ordered the parts and I saw them when they arrived. After installation, I noticed a slight howl at 50 to 51 MPH but only when on level roads but not going down grades. What is the problem? Will it get worse? We only use it as a second vehicle for maybe 5000 miles per year tops and carrying no heavy loads. N.A. Colon, MI

A. I've gotten several letters regarding this problem on GMC and Chevy half-ton trucks on the same vintage. A couple of them had new ring-and- pinion sets installed twice and each time the noise remained but at a different speed and/or a different decibel level. It's really tough to get the gears set up spot-on in those G.M differentials (I've done many of them in the past) and your present problem is not the fault of the technician who did the job. One reader even had a complete factory-new rear axle assembly installed and it still "sang." Usually the noise doesn't get worse and most owners learn to live with it.

Q. I have a 1992 Toyota Camry LX that I recently bought. It has only 38,000 miles on it and I plan to drive it to Florida in the near future. I had a Toyota specialist do a check-up and service for me and he said that one of the rear shock absorbers is leaking. He said that he can install a used one from a low-mileage wrecked Camry for about half the price of a new one which is expensive. I'm on a somewhat limited budget which is causing my move to Florida and I'd like to save money if I can. J.R. Las Vegas, NV

A. I don't disapprove of used parts but buying a used mechanical part of any kind is a crap-shoot especially if you're moving out of the repair shop's home area. If you can check the mileage and condition of the "donor" car, you'll get an idea of its condition and mileage.