Automania/Repair & Maintenance

AUTO QUESTIONS AND ANSWERS FOR WEEK 09

by Bob Hagin

Q. I have a 1994 Mercedes-Benz E320 four-door sedan. On it are Michelin MXV4 195X15HR65 steel-belted tires. A long time ago, prior to steel-belted radials, we used to rotate to all four positions in an "X" pattern. When steel-belted radials were introduced, we were told to only rotate front to back and never switch sides. This is also the recommended procedure in my Mercedes manual. Supposedly, switching sides would "work" the steel weave and weaken it. Recently I was at an independent tire shop and they rotated my tires from side to side. They said it was the normal procedure and that it was not a problem to do this. Has something changed in tire technology to allow us to rotate tires from side to side, was I using incorrect information all these years, or was my tire rotator wrong? If I had a choice, I would rather rotate all four positions so as to get the most even wear. I now rotate them every 5000 miles but if the weave is a concern, I would consider switching sides once every 20,000 miles which would result in switching sides only once or twice at most. J.M. Bakersfield, CA

A. When I started busting and rotating tires many years ago, I was instructed to make it a five-way switch which included the full-sized spare. This is no longer possible in most cases because of the cheap "space-saver" emergency tires now in use. When steel-belted tires came out, I too was told not to cross-switch them because the they would take a "set" in operation and by changing direction, the set between the tread and the steel weave would reverse itself, loosen the bond between the two and the tread would pitch off. I called the Michelin folks in Greenville, South Carolina and was told that the company recommends a rotation at 5000 to 6000 miles. The pattern on a rear drive-car like your Mercedes is to put the rear tires forward on the same side of the car and to cross the front tires when they are installed in the rear. I think that a rotation at 20,000 miles might disturb a radical set that the tires had developed over such a prolonged period of time.

Q. I am the owner of a 1986 Ford Bronco II. It has a 2.9 liter V6 engine, four-wheel drive and a manual five speed transmission. I would like to convert this car to an automatic transmission and if I do so, what are the modifications I would have to make? I am a weekend mechanic and this is just a hobby and experimental vehicle. A.E. Norfolk, VA

A. The easiest way to undertake a job like the one you're considering is to locate and buy a wrecked Bronco II of the same vintage as yours but with an automatic transmission. In assembling a kit car using a body and chassis kit, this is referred to as stripping a "donor" car. The procedure would than be to transfer all the major and ancillary parts from the donor onto the vehicle you're converting. This would save you from having to locate major items like the transmission and drive line separately and then having to fabricate all the brackets, mounts, cables, etcetera, that would be needed to get everything working. Your conversion would even need another radiator that contained the intercooler system to cool and/or heat the automatic transmission fluid. The last time I did a conversion like the one that you're proposing was over 40 years ago. It involved a '54 Hudson Jet and it was indeed, the last one.

Q. I have a radiator cap mascot that my dad gave me. It's a devil's bust that is thumbing it's nose with its right hand. It worth anything? Who could I contact to get a date and evaluation on this item?. K.K. Olympia, WA

A. I have a pre-World War I St. Christopher's medal and was given an evaluation of it by the Automobile Objects d'art Club at 610-432-3355. Its address is 252 N. 7th St. Allentown, PA 18102.