VW Golf - tankslapper/steering shimmy

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Sun 8 Jul 2007 23:25
VW Golf - tankslapper/steering shimmy - Dyaneman
My girlfriend's 1988 Golf GTI 8valve has a tendency to develop what I would describe in motorcycling parlance as a 'tankslapper' when you hit the right (or wrong) bump whereby a fairly impressive steering shimmy sets up necessitating either braking or accelerating to make the wobbling stop. It seems to be the offside front wheel which is sensitive to setting this chain of events in motion.

I have jacked each of the wheels up in turn and can detect no play in the suspension or steering, and am wondering what else could cause this behaviour?

Two of the (alloy) wheel rims have been flattened by contact with something kerblike which leads me to consider a bent wheel as a possible candidate, but I'm basing this suspicion on supposition rather than any experience or knowledge in this area...

Cheers,
Jonathan.

PS, I have suspected for some time that the car could do with the tracking done, as the steering has that lightness when turning into a bent that suggests excess toe-out, but surely I am right in thinking that a geometry problem could not cause a shimmy?
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Sun 8 Jul 2007 23:34
Golf tankslapper/steering shimmy - Number_Cruncher
Check to see if the dampers are doing anything. This is a fairly typical symptom of a damper where the valves have failed open, and although there might not be any external leakage, the damper may not be providing any resistance.

Number_Cruncher
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Sun 8 Jul 2007 23:47
Golf tankslapper/steering shimmy - Dyaneman
The dampers seem ok doing the bounce test on the wings, and there does not seem to be any noticeable bounciness when driving the car.

Cheers,
Jonathan.
Check to see if the dampers are doing anything.
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Mon 9 Jul 2007 00:04
Golf tankslapper/steering shimmy - 659FBE
Replace the damaged wheel with the spare and do a rough tracking check by running your hand lightly across the crown of the tyre you have taken off.

If, when running your hand lightly across the tread (not around it) you feel more roughness or resistance one way than the other, this is an indication that the rubber is being "sawtoothed" or scuffed by incorrect tracking - time to do a proper check.

Shimmying is usually caused by free play somewhere in the suspension, usually in conjunction with poor damping. Any signs of oil leakage?

659.
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Mon 9 Jul 2007 00:11
Golf tankslapper/steering shimmy - bell boy
i would go with the shocker even though it passes a bounce test
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Mon 9 Jul 2007 11:19
Golf tankslapper/steering shimmy - yorkiebar
Agree with shock absorbers, but just check each coil spring carefully for breakage.
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