ChicaneS2

Hi all

Recently purchased an 08 ap2 with under 30K miles. When going over bumps and terrible uneven roads the only thing that rattles is the soft top on the drivers side. No problem, I can live with that.

The issue is very specific. When I apply the brakes right when the tires hit the speed bump, there is a very audible rattle almost sounds like a license plate rattle from inside the cabin. I’ve tightened the license plate frame down but that isn’t the cause. I can also “feel” this rattle when it occurs. This isn’t ABS as I am slightly on the brake pedal. Last time the car was in the air I didn’t notice Any free play in the calipers.

the car can still brake fine and doesn’t rattle at all unless in this very specific situation. Braking over an uneven road surface does not create a rattle either.

Does anyone know what it is or has anyone experienced this?

thank you

Deckoz

I'm pretty positive it's ABS, as your situation, literally is the only time during regular driving when my ABS goes off. It's because the tires loose traction on the painted speed bumps. And the ABS then goes needlessly pumping away for a split second, even though you barely touched the brakes

ChicaneS2

Thanks for the reply

im aware of the pulsing sensation in the brakes during ABS engagement but in this situation I hear and feel some kind of rattle once I hit the speed bump even if I’m lightly on the brake pedal. Would that be ABS too?

Chuck S

You hearing a rattle? * Or feeling a vibration? .. where? (Nomenclature helps.)

-- Chuck

* a rapid succession of short, sharp, hard sounds.

Deckoz

As Chuck said, an idea of where it's coming from would help

ChicaneS2

I am hearing a rattle ONLY when going over a speed bump with the brake engaged (usually happens when brake is engaged right before speed bump. When you don’t notice a speed bump and braked at the last second) . I can also feel the vibrations through the brake pedal at the same time of the rattling. I’m aware of the ABS pulsing feeling through the brakes when it is engaged on a relatively flatter surface (Pressing the brake pedal all the down).

ChicaneS2

DeckoZ , could it be the ABS engaging at such a low speed (over a speed bump 4-8 mph)? Instead of the usual pulsing, *chug chug chug at higher speeds, It’s rattling the pads against the rotors due to low speeds?

B serious

Unplug the ABS fuse or one of the wheel sensors.

Check if the rattle is gone.

This is tough over the internet also. Might be worth taking your car somewhere to have it inspected.


You say you didn't notice any freeplay in the calipers.
But have you checked with a torque wrench or any tool?

Are your pad clips missing or damaged?

What have you actually checked?

Deckoz

Yea it's a completely different feeling at slow speeds.

Like I said, going over painted, or concrete speed bumps is the only time it happens to me, and it's a mixture of the wheel slip and abs.

Going over speed bumps that are asphalt and not painted I don't experience this. Only speed bumps that are 'slippery'

This happens in all of my cars. It feels very violent, completely different feeling from high speed ABS.

Try to find a asphalt speed bump that isn't painted, I'm betting it won't happen.