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Old 08-05-2004, 10:51 AM
230/8 230/8 is offline
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Join Date: Mar 2004
Posts: 758
It is my understanding that front suspension geometry was redesigned on the 560SL, and possible the 380SLs, too. This resulted in a much higher caster setting, in the 9 - 10 degree range, I believe, as opposed to the 3.5 - 4 degree settings for the earlier cars. With high caster settings there is a normal tendency for wheels to feel loose or vague, or even to wobble a bit (sort of like the action of the wheels on a grocery cart) at the extremes when turned, particularly when going in reverse. (It helps to understand that with positive caster in the steering, turning the wheels actually results in a slight lifting of the car's front end as the steering knuckle pivots around a virtual axis that intersects the ground ahead of the wheel contact patch when it is in the normal straight ahead position. This slight lifting accounts for the natural self-centering action as the steering returns to straight ahead as the car settles itself down.)

As pointed out earlier, the sensation of vagueness or looseness can be amplified due to the design of the worm-sector recirculating ball steering used on these cars. The high caster design is common to MB cars in general, and to combat the tendency to wobble, or shimmy, MB includes a steering damper, a horizontal shock absorber. You might check the condition of your steering damper and replace it if in doubt about its ability to control unwanted motion.

If you have ever attended a local drag strip, or watched ESPN racing shows on the history of drag racing, when the old-style front engine fuel dragsters were running, you may have noticed how their front ends were designed with a very simple solid beam axle laid way back at a steep caster angle of nearly 45 degrees. This served to stabilize the steering at their extreme high running speeds but, when the cars were pushed backward to align them correctly at the start line, the wheels would often wobble severely when moving in reverse. New top fuel cars use a different design now.

Just a thought from someone whose big behind no longer fits into those teeny little narrow seats...

230/8
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