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Automania/Repair & Maintenance
AUTO QUESTIONS AND ANSWERS FOR 1996 WEEK 10
by Bob Hagin
Q. I just replaced the clutch components on my '85 Dodge Caravan 2.2 liter with a five-speed manual transmission, at 110,000 miles. I also had the flywheel resurfaced. The clutch no longer jerks or chatters when starting from a stop under load but another is still apparent. When using reverse and climbing the incline of my short driveway which only takes a few seconds, there is a strong smell of burning clutch or brake linings which is still obvious after the vehicle has been parked for several hours. I don't smell it when pulling up the driveway forward.
A. That burning-brake smell is one that is hard to miss and hard to get rid of, too. There's only one thing that I know of that can cause that smell and it's slippage of the fiber-covered disk between the clutch pressure plate and the flywheel but there's a couple of possible causes. If the clutch release bearing (the device that operates the clutch pressure plate) is applying any pressure at all to the pressure plate, it makes the disk slip against the flywheel and overheats. Also, if the pressure plate doesn't exert enough pressure against the disk, the clutch will slip when a big load is thrown against it. This sometimes happens when a rebuilt pressure plate is installed and the rebuilder made its spring pressure too light. If a "dished" flywheel is improperly refaced, it can cause slipping, too. I think that the reason that you experience the problem in reverse but not in first gear is that reverse is a lower ratio, and your clutch is slipping. Higher engine speeds multiplies engine torque to the point where the slippage is noticeable. If you had a pro shop do the job, take it back immediately.
Q. I have a 1994 Plymouth Sundance/Duster with the 2.5 liter engine and an automatic transmission. It now has 13,000 miles on it but at 8000 miles I noticed a rotten egg odor coming from under the car. I bought the car new from a Plymouth dealer so I took it back to his service department. The mechanics there checked it out and found that the source of the odor was the catalytic converter. They told me that the engine was burning very clean and changing the converter would not help. Is this true? I've tried different brands of gasoline, too.
A. The problem isn't in the converter - it's doing its job too well. It's being overheated by an over-rich fuel mixture (too much gasoline and not enough air) and is causing the sulfur in the gasoline to break into hydrogen sulfide (H2S). This is the odor you're smelling. The fuel/air mixture in most of today's engines is computer-controlled so the problem may well be an electronic malfunction. On older engines, the problem was very often traced to one of several malfunctions (localized vacuum leak, faulty spark plug wires, etc.) that let unburned fuel pass into the converter. The emission control system on your Plymouth is covered under a federally mandated warranty so have your dealer call in the factory rep if his mechanics can't cure the problem since there may be a recall. A high sulfur content in the gas your using could be a possible cause, also.
Q. There's a photo on the wall of a local restaurant that shows a group of old race cars on the starting line of what appears to be a track made of wooden planks. The waitress says that it was taken at a race held in San Francisco before World War I. Were wooden race tracks common at that time and were streets made of wooden planks too?
A. "Board tracks" were a holdover from bicycle racing that was popular at the turn of the century. They were lots cheaper to built into high- bank tracks than asphalt and allowed very high speeds. Chris Economacki, the race announcer, is doing a book on the subject and would like to see a copy of the photo. He's at NSSN, Box 608, Ridgewood, NJ 07451.
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