random steering wobble

Hi there !
Looks like our hiace didn't enjoy the gravel roads in Costa Rica, the steering is randomly wobbling, at any speed, even at very low speed. I almost have the feeling to have square tires.
Surprisingly, the wobble may disappear for a few miles and then come back for no apparent reason.
At 40mph, it's more serious, the car is shaking a bit as well, and if I release the steering, it's moving from left to right. No noise. It may disappear for no reason......this random thingy is annoying.

we did the obvious :wheel balancing, but no difference. I don't think a wheel alignment would fix the problem, and we don't have uneven wearings on the tires. We flushed the power steering, still no difference. We went to 3 different places in San Jose, including Toyota, and they didn't find anything, apart from stealing dollars from our pockets.

Our front tires are old, and may need replacement, I guess next step would be to rotate the tires, and see if that makes any difference.

The guys at Toyota spend time to inspect the suspension and they didn't find anything suspicious, but at the same time, they didn't source the problem.
Any idea ?

Cheers,

David

Tyres gone out of round? I had that happen with a pair of cheapy Federals that the dealer had put on.

Hi MalL, thanks for the advice, I'm also thinking tyres are the problem as wobble is present at very low speed, like on the driveway.
But a balance machine should notice this kind of problem, right ? I'll try to get a second jack today and rotate the tyres.

Good luck with the rotation, at least it might move the problem from the front to the rear which would help with the diagnosis. I don't know that a balance machine would pick up out of round - the tyre mass could be evenly distributed but only road contact brings out the irregular shape. I'm just guessing though.

The dirt road didn't look that bad, but was enough to deform our 2 front tyres, plus while holding the front right tyre at 12 and 6 o clock, the wheel was a bit loose, but easy to fix.
So when they balance the tyre, they usually put a shield for safety reasons, so you don't see anything. But if you don't use it, you cleary see that the tyre is deformed while he's rotating.

Yeah we're back on the road !
thanks MalL !

That's great!