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I just bought a 91 Classic Convertible. It only has 17,200 miles on the clock and in beautiful condition. I've noticed vibration of differing severity, mostly above 40mph, sometimes it can get very uncomfortable. I went ahead and balanced all the wheels and got the alignment done. After that it seemed to be much better (but I didn't drive above 50mph initially). Now after leaving it for a week in the garage, I drove it on the freeway and it came back worse than before. What else could be causing that? It's definitely intermittent - any advice would be most welcome.
Thanks! - I thought it might be something like that. It's disappointing as the miles are so low and with very little sign of wear or corrosion, but i have a feeling it's been sitting for a few years here and there through it's life, that may be the cause of any failures.
That is a gorgeous looking XJS! However a 28 year old car with 17,000 miles is not the same as a newer car with 17k on the clock. Some parts degrade over time regardless and cars need to be driven. The mileage averages out to roughly 600 miles per year. I would imagine due to the low miles all of the suspension bushings are original, 28 year old rubber, with possible dry-rot from sitting for so long. I would inspect those and go from there.
seems the aliment shop would have checked for things like loose wheel bearings bad ball joints and tie rod ends ect, but it wouldn't hurt to go threw all that stuff again. but the first thing i would do is rotate the tires and see if the vibration moves from front to back or back to front. and go from there.
How did they balance the wheels? Square wheels & tires would balance perfectly on an ordinary balancer, but it doesn't mean you'll get a smooth ride. Until you have had them balanced on a Hunter Roadforce balancer, and had results with minimal runout, the wheels/tires have not been eliminated as a cause.
My last set of Pirellis (P Zero A/S) on the XJR were the worst tires I've ever had for flatspotting when parked for a while. The tires would shake your teeth out for the first few miles, and then get better, but it never went away entirely. I'll never go near Pirellis again as long as I live. I have Michelins on the XJS and Volvo V60 and the balancing is always perfect.
I notice you have Pirelli P600s. How old are they? With only 17.200 miles on the car, they might actually be original to the car, which is a fairly terrifying prospect. I get nervous when tires are more than 5 years old.
If Tire condition and alignment arn't the issue start looking into re-doing the front end bushings and most important, and often forgot, the sub-frame mounts.
Personally I got so sick of it I had the entire car front (and rear) redone in Superflex poly bushings except one lower? bushing on both sides and uprated rubber where poly was not available and the overall handling is still extremely smooth but now far far more darty and responsive.
I, and another guy here chased a vibration/juttering for months until finally he found the cause in cracked frame mounts.
Please consider the age of the rubber, milage is also abit of a negative...ideally you want a driven car not a once-a-month pavement princess. If your bushings are on the way out your rubber fuel lines might be next.
How did they balance the wheels? Square wheels & tires would balance perfectly on an ordinary balancer, but it doesn't mean you'll get a smooth ride. Until you have had them balanced on a Hunter Roadforce balancer, and had results with minimal runout, the wheels/tires have not been eliminated as a cause.
My last set of Pirellis (P Zero A/S) on the XJR were the worst tires I've ever had for flatspotting when parked for a while. The tires would shake your teeth out for the first few miles, and then get better, but it never went away entirely. I'll never go near Pirellis again as long as I live. I have Michelins on the XJS and Volvo V60 and the balancing is always perfect.
I notice you have Pirelli P600s. How old are they? With only 17.200 miles on the car, they might actually be original to the car, which is a fairly terrifying prospect. I get nervous when tires are more than 5 years old.
I can second that. My XJ8 always had cold flat spots which took about 15 mins of driving to get rid of. My super light Fiat 124 Spider has flat spots after sitting for 2 days. So I drive it daily instead so they can't occur
12-30-2018, 03:56 AM
91 XJS Vibration/steering wobble issue (not wheel balance)
