Regular twang revisited...

[GTI_PAPA]

Hey guys,

I have had a regular twang (sounds like flicking a ruler) under my car since new. Have been back to VW several times, and they can find anything. Have been reading other forums etc, and have stumbled across one that might make sense. The twang/vibration can be felt through the brake pedal, which leaves the question, "Might it be a sticky hand brake cable that suddenly, fully releases causing this?"

Any suggestions would be appreciated,
Con...

[Ben_GTI]

Is it when you first start moving? I think this is an ABS test....

Otherwise, if you car sits for a while, it is the handbrake stuck to the disc... it does it once then goes away...

If you heard a knock when you brake in reverse, its just calipers sliding around and there isn't much you can do about it.

[noone]

Does this only happen when braking?

[danish]

When you say you can feel it in the pedal, does the pedal lose a bit of its resistence as well?

I encounter a similar problem of shuddering brakes accompanied by a scraping sound occasionally when I brake. However I can only make it happen when on very loose surfaces (like gravel) or going down my driveway, which is quite steep.

Seems like an ABS issue to me, although I really don't like the sound of the scraping!

[ACTGTI]

danish - That's just the ABS working isn't it?

Everyone should familiarise themselves with what happens when ABS (and ESP) is working. It's quite dramatic on the brake pedal and it doesn't take much for it to kick in on a gravel road.

Take out all your loose items in the car (important - if you don't, everything in the back will end up in the front), drive out to a country road and at 80km/h hit the brakes as hard as you can (make sure no-one is behind you). You should feel your brake pedal shuddering under your foot. This is normal. You will be surprised how well the Polo pulls up as well.

You'll also feel it if you take a corner too quickly as ESP tries to apply brakes to various wheels to straighten the car up and avoid a spin.

[break]

I have a similar issue with the ESP system.

I find it cuts in far too early on some surfaces, where it comes in at exactly the right time on others.

Do you notice any consistency on which surfaces and what speed this occurs at?