I had a front wheel drive car that indulged in occasional fits of madness
like yours, swinging the steering wheel violently and feeling like a terrier
shaking a rat. Banging the brake pedal hard usually stopped it, but the
problem was partial seizure of the right front CV joint.

It would lock up and cause the symptoms.

Just a possibility.

On 11/6/06, Rick Koller <rkoller@helix.nih.gov> wrote:
>
> Greetings All,
>         I need help diagnosing a scary situation that has been
> intermittent
> so far. Here's the scenario:
> I'm driving my syncro westie straight down the interstate cruising at
> 65 mph, suddenly the steering wheel begins to shimmy dramatically,
> violent enough that I'm looking for the shoulder fast. I slow down
> and stop. Get out and look over the suspension parts, pulling and
> tugging on tierods, front and rear axles. I jack up the van and check
> for excessive play in the wheel bearings and any dangerous rumbling
> sounds from rotating wheels. I find nothing. I get back in the van
> and continue on and the van drives completely normally. No shimmy or
> shakes or rumbles. I'm wary now so prepare myself for another
> episode. Nothing happens for 3 weeks during this time I drive the
> camper daily at different speeds. Nothing happens until yesterday and
> the same scenario occurs, driving again at cruise speed of 65 and the
> dreadful shimmy starts out of nowhere. I pull over  and do the checks
> again, still nothing obvious. I go on and the van drives ok below
> 40mph, as I get up speed the shaking starts again, this time it has
> some rumble or rubbing sound, can't tell what. The sound and shake
> goes away when I stop. I decide to try again and I get off the
> interstate to travel on local roads and keep my speed down. No
> problems at speeds below 40 mph, I don't push it and get home where I
> again jack up the camper and pull and rotate suspension drive axle
> parts. Still nothing obvious. Upper ball joints only a couple years
> old, new front axle on one side. Anyone have insight on this one? I
> scanned the archives but only came up with the usual bad tire
> scenario. Seems unlikely its a tire because of the intermittent
> nature, but who knows. Anyone?
> Thanks,
> Rick Koller
>

--
Jake
1984 Vanagon GL
1986 Westy Weekender "Dixie"
www.crescentbeachguitar.com