Avensis Low frequency warble noise

[Techno652]

I bought my second Avensis last December. A nice 62 plate D-4-D but have been plagued with wind noise and an audible low frequency warble sound when the car travels over rough tarmac and or speed bumps. The wind noise I think I can deal with but the low frequency noise is proving very difficult to pin point. So far I have established the noise can be replicated easily and dissipates and or is eliminated when a very slight amount of break pressure is applied. When i say slight, its not enough for the car to actually slowdown.

Does anyone know if there is a problem with the break assembly and or the suspension / steering bushes which may be placed under a little more pressure when in the above situation?

The noise is driving me mad. The Older D-4-D model suffered the same sort of thing but developed into a knock. Toyota dealer cant even hear it!!!

Do I need help?? Am I paranoid or is there a problem which people know about. This is my ' Help me, Obi-Wan Kenobi, you're my only hope.' moment on this forum. Please accept my apologies if this has already been answered in another thread. I tried to searching but found nothing.

[alan333]

I've had this on two T25's and a T27.  The slider pins on the brake calipers can wear, giving a light rattle sound.  As you say, it's difficult to pin-point whether it's coming from the front or rear, it's more prevalent on slight rough ground at slow speeds, and goes away with a slight touch of the brakes.  It's been mentioned on here in the past, and my local Toyota dealer were also aware of the problem so I'd like to think yours should also know about it.

On both my T25's the problem was with the front calipers.  I fitted new slider pins to one of my T25's which completely cured it, and I packed the sliders with the proper grease on the other T25 which cured it for a few months.  My T27 was attended to at each dealer service, but I reckon they also only packed the sliders since it came back after a couple/few months too.

To verify your problem: take a (front?) wheel off, grab the whole caliper assembly with two hands, one at the outer and one at the inner, and attempt to move it out/in.  If you have movement then that's your problem.  Also bear in mind, dependant on how new/worn your brake pads are, maybe your slider pins are at their 'outmost' point, which might aspirate the problem. 

[Techno652]

Thanks Alan. Your detailed and swift response is much appreciated. I'll check this out when I get home on my TR.